PRIME GROUP REALTY TRUST
10-Q, 1999-11-12
REAL ESTATE INVESTMENT TRUSTS
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                                  UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D. C. 20549

                                    FORM 10-Q

          (X) QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15 (d) OF THE
                         SECURITIES EXCHANGE ACT OF 1934

                For the quarterly period ended September 30, 1999

          ( ) TRANSITION REPORT PURSUANT TO SECTION 13 OR 15 (d) OF THE
                         SECURITIES EXCHANGE ACT OF 1934

                         Commission File Number: 1-13589

                            PRIME GROUP REALTY TRUST
             (Exact name of registrant as specified in its charter)


          MARYLAND                                              36-4173047
(State or other jurisdiction of                               (I.R.S. Employer
 incorporation or organization)                              Identification No.)

77 West Wacker Drive, Suite 3900, Chicago, Illinois                 60601
     (Address of principal executive offices)                     (Zip Code)

                                 (312) 917-1300
              (Registrant's telephone number, including area code)

Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the  preceding 12 months (or for such  shorter  period that the  registrant  was
required  to file  such  reports),  and  (2) has  been  subject  to such  filing
requirements for the past 90 days. Yes x No __

Indicate the number of shares  outstanding  of each of the  issuer's  classes of
common stock, as of the latest practicable date:

At November 11, 1999, 15,135,827 of the Registrant's Common Shares of Beneficial
Interest were outstanding.






                                      -1-
<PAGE>
                            PRIME GROUP REALTY TRUST
                                    FORM 10-Q

                                      Index


                                                                            Page
                                                                            ----
PART I:  FINANCIAL INFORMATION

Item 1.  Financial Statements (Unaudited)

         Consolidated Balance Sheets as of September 30, 1999 and
           December 31, 1998..............................................     3

         Consolidated Statements of Income for the Three Months
           Ended September 30, 1999 and 1998..............................     4

         Consolidated Statements of Income for the Nine Months
           Ended September 30, 1999 and 1998..............................     5

         Consolidated Statements of Cash Flows for the Nine Months
           Ended September 30, 1999 and 1998..............................     6

         Notes to Consolidated Financial Statements.......................  7-15

Item 2.  Management's Discussion and Analysis of Financial Condition
           and Results of Operations...................................... 15-28

Item 3.  Quantitative and Qualitative Disclosures About Market Risk.......    29


PART II: OTHER INFORMATION

Item 1.  Legal Proceedings................................................    30

Item 2.  Changes in Securities and Use of Proceeds........................    30

Item 3.  Defaults Upon Senior Securities..................................    30

Item 4.  Submission of Matters to a Vote of Security Holders..............    30

Item 5.  Other Information................................................    30

Item 6.  Exhibits and Reports on Form 8-K.................................    30


Signatures
















                                      -2-
<PAGE>
<TABLE>
                          PART I. FINANCIAL INFORMATION
ITEM 1.  FINANCIAL STATEMENTS

                            PRIME GROUP REALTY TRUST
                           Consolidated Balance Sheets
                       (000's omitted, except share data)
                                  (Unaudited)
<CAPTION>
                                                    September 30,  December 31,
                                                        1999           1998
                                                    ------------   ------------
<S>                                                 <C>            <C>
                    ASSETS
Real estate, at cost:
  Land........................................      $    137,231   $    139,505
  Building and improvements...................           681,951        655,154
  Tenant improvements.........................            30,233         48,372
                                                    ------------   ------------
                                                         849,415        843,031
  Accumulated depreciation....................           (31,572)       (24,756)
                                                    ------------   ------------
                                                         817,843        818,275
  Property under development..................           141,471         51,376
                                                    ------------   ------------
                                                         959,314        869,651
Mortgage note receivable......................            77,149         63,270
Cash and cash equivalents.....................            10,173         46,500
Tenant receivables, net.......................            12,473          7,288
Restricted cash escrows.......................           118,052         53,820
Deferred rent receivable......................             8,314         39,062
Deferred costs, net...........................            22,985         32,891
Loans receivable from services company........             6,171          7,055
Other.........................................            21,679         44,977
                                                    ------------   ------------
Total assets..................................      $  1,236,310   $  1,164,514
                                                    ============   ============

     LIABILITIES AND SHAREHOLDERS' EQUITY
Mortgage notes payable........................      $    513,513   $    518,718
Credit facilities.............................            15,637              -
Bonds payable.................................            74,450         74,450
Accrued interest payable......................             2,610          2,440
Accrued real estate taxes.....................            36,814         29,657
Accounts payable and accrued expenses.........            27,678         26,068
Liabilities for leases assumed................             3,242          4,792
Dividends payable.............................             8,104          8,080
Other.........................................             8,409          4,523
                                                    ------------   ------------
Total liabilities.............................           690,457        668,728
Minority interests:
  Operating Partnership.......................           168,869        144,781
  Other.......................................             1,000          1,000
Series A - Cumulative Convertible Redeemable
  Preferred Shares............................            39,667              -
Shareholders' equity:
  Series B - Cumulative Redeemable Preferred
    Shares....................................                40             40
  Series A - Cumulative Convertible Preferred
    Shares....................................                 -             20
  Common Shares...............................               151            151
  Additional paid-in capital..................           320,386        360,017
  Retained (distributions in excess of)
    earnings..................................            15,740        (10,223)
                                                    ------------   ------------
Total shareholders' equity....................           336,317        350,005
                                                    ------------   ------------
Total liabilities and shareholders' equity....      $  1,236,310   $  1,164,514
                                                    ============   ============
<FN>
                See notes to consolidated financial statements
</FN>
                                      -3-
</TABLE>
<PAGE>
<TABLE>
                            PRIME GROUP REALTY TRUST
                        Consolidated Statements of Income
                       (000's omitted, except share data)
                                   (Unaudited)
<CAPTION>
                                                          Three Months Ended
                                                            September 30,
                                                    ---------------------------
                                                        1999           1998
                                                    ------------   ------------
<S>                                                 <C>            <C>
REVENUE
Rental........................................      $     32,474   $     28,050
Tenant reimbursements.........................            12,620          9,488
Mortgage note interest........................             1,707          1,415
Other.........................................             2,995          2,298
                                                    ------------   ------------
Total revenue.................................            49,796         41,251

EXPENSES
Property operations...........................            11,958          8,817
Real estate taxes.............................             7,221          6,869
Depreciation and amortization.................             8,744          6,611
Interest......................................            10,899          7,615
General and administrative....................             1,665          1,651
                                                    ------------   ------------

Total expenses................................            40,487         31,563
                                                    ------------   ------------

Income before gain on sales of real estate,
  minority interests and extraordinary item...             9,309          9,688

Gain on sales of real estate..................            48,125              -
                                                    ------------   ------------
Income before minority interests and
  extraordinary item..........................            57,434          9,688

Minority interests............................           (22,499)        (2,704)
                                                    ------------   ------------
Income before extraordinary item..............            34,935          6,984

Extraordinary loss on extinguishment of
 debt, net of minority interests of $576......              (829)             -
                                                    ------------   ------------
Net income....................................            34,106          6,984

Net income allocated to preferred
  shareholders................................            (3,037)        (2,950)
                                                    ------------   ------------
Net income available to common shareholders...      $     31,069   $      4,034
                                                    ============   ============
Net income available per weighted-average
  common share of beneficial interest
  - basic.....................................      $       2.05   $       0.26
                                                    ============   ============
Net income available per weighted-average
  common share of beneficial interest
  - diluted...................................      $      2.04    $       0.26
                                                    ============   ============
<FN>
                See notes to consolidated financial statements.
</FN>
                                      -4-
</TABLE>
<PAGE>
<TABLE>
                            PRIME GROUP REALTY TRUST
                        Consolidated Statements of Income
                       (000's omitted, except share data)
                                   (Unaudited)
<CAPTION>
                                                          Nine Months Ended
                                                            September 30,
                                                    ---------------------------
                                                        1999           1998
                                                    ------------   ------------
<S>                                                 <C>            <C>
REVENUE
Rental........................................      $     98,806   $     69,525
Tenant reimbursements.........................            39,005         27,889
Mortgage note interest........................             4,817          4,429
Other.........................................             9,159          5,083
                                                    ------------   ------------
Total revenue.................................           151,787        106,926

EXPENSES
Property operations...........................            33,205         20,758
Real estate taxes.............................            26,370         19,101
Depreciation and amortization.................            25,382         18,186
Interest......................................            32,822         22,091
Loss on land development option...............               600              -
General and administrative....................             5,472          4,695
                                                    ------------   ------------
Total expenses................................           123,851         84,831
                                                    ------------   ------------

Income before gain on sales of real
  estate, minority interests and
  extraordinary items.........................            27,936         22,095

Gain on sales of real estate..................            52,482              -
                                                    ------------   ------------
Income before minority interests and
  extraordinary items.........................            80,418         22,095

Minority interests............................           (29,247)        (7,022)
                                                    ------------   ------------
Income before extraordinary items.............            51,171         15,073

Extraordinary loss on extinguishment of debt,
  net of minority interests of $576 in 1999
  and $375 in 1998............................              (829)          (525)
                                                    ------------   ------------
Net income....................................            50,342         14,548

Net income allocated to preferred
  shareholders................................            (9,067)        (4,991)
                                                    ------------   ------------
Net income available to common shareholders...      $     41,275   $      9,557
                                                    ============   ============

Net income available per weighted-average
  common share of beneficial interest
  - basic.....................................      $       2.73   $       0.65
                                                    ============   ============

Net income available per weighted average
  common share of beneficial interest
  - diluted...................................      $       2.72   $       0.65
                                                    ============   ============
<FN>
                 See notes to consolidated financial statements.
</FN>
                                      -5-
</TABLE>
<PAGE>
<TABLE>
                            PRIME GROUP REALTY TRUST
                      Consolidated Statements of Cash Flows
                       (000's omitted, except share data)
                                   (Unaudited)
<CAPTION>
                                                           Nine Months Ended
                                                            September 30,
                                                    ---------------------------
                                                        1999           1998
                                                    ------------   ------------
<S>                                                 <C>            <C>
OPERATING ACTIVITIES
Net income                                          $     50,342   $     14,548
Adjustments to reconcile net income to net
 cash provided by operating activities:
   Amortization of costs for leases assumed
     (included in rental revenue).............               736            852
   Interest income and development fees added
     to mortgage note receivable principal....            (1,553)             -
   Depreciation and amortization..............            25,382         18,186
   Gain on sales of real estate...............           (52,482)             -
   Net gain on treasury lock terminations.....              (615)             -
   Loss on land development option............               600              -
   Equity in loss (earnings) of
     unconsolidated investments...............               617           (144)
   Minority interests.........................            29,247          7,022
   Extraordinary items, net...................               829            525
   Changes in operating assets and liabilities:
    Increase in tenant receivables............            (6,009)          (805)
    Increase in deferred rent receivable......            (1,845)        (1,053)
    Decrease (increase) in other assets.......             8,316         (6,414)
    Increase in accrued interest payable......               170            728
    Increase in accrued real estate taxes.....            16,878         13,921
    (Decrease) increase in accounts payable
      and accrued expenses....................            (3,645)           999
    Decrease in liabilities for leases
      assumed.................................            (1,197)          (968)
   (Decrease) increase in other liabilities...              (291)         6,261
                                                    ------------   ------------
Net cash provided by operating activities.....            65,480         53,658

INVESTING ACTIVITIES
Expenditures for real estate and equipment....          (298,939)      (281,974)
Net proceeds from sales of real estate........           150,121              -
Leasing costs.................................            (5,501)        (2,174)
Additional advances on mortgage note
  receivable..................................           (12,326)        (2,079)
Increase in restricted cash escrows...........           (64,232)       (46,575)
Repayments (loans) from services company......               884         (2,779)
                                                    ------------   ------------
Net cash used in investing activities.........          (229,993)      (335,581)

FINANCING ACTIVITIES
Financing costs...............................            (3,793)       (19,520)
Deposits returned on treasury lock
  agreements..................................            15,256              -
Proceeds from mortgage notes payable..........           168,700        291,656
Net proceeds from (repayment of) credit
  facilities..................................            15,637        (20,300)
Repayment of mortgage notes payable...........           (32,389)       (84,611)
Repayment of mortgage note payable
  - affiliate.................................                 -         (3,984)
Contributions from minority interest - other..                 -          1,000
Distributions to minority interests
  - Operating Partnership.....................           (10,537)        (8,641)
Proceeds from the sale of Series B
  - preferred shares..........................                 -         94,369
Series A - preferred shares transaction fee...              (400)             -
Proceeds from the sale of common shares.......                 -         47,194
Common stock repurchases......................                 -         (4,013)
Dividends paid to Series B - preferred
  shareholders................................            (6,750)          (641)
Dividends paid to Series A - preferred
  shareholders................................            (2,230)        (1,745)
Dividends paid to common shareholders                    (15,308)       (12,672)
                                                    ------------   ------------
Net cash (used in) provided by financing
  activities..................................           128,186        278,092
                                                    ------------   ------------
Net decrease in cash and cash equivalents.....           (36,327)        (3,831)
Cash and cash equivalents at beginning of
  period......................................            46,500         11,969
                                                    ------------   ------------
Cash and cash equivalents at end of period....      $     10,173   $      8,138
                                                    ============   ============
<FN>
                 See notes to consolidated financial statements.
</FN>
                                      -6-
</TABLE>
<PAGE>
<TABLE>
                            PRIME GROUP REALTY TRUST
                      Consolidated Statements of Cash Flows
                       (000's omitted, except share data)
                                   (Unaudited)


During the nine months ended  September 30, 1999, the Company sold the following
assets and liabilities (see Note 5 - Recent Developments):

<CAPTION>
                                                              Nine Months Ended
                                                                September 30,
                                                              -----------------
                                                                    1999
                                                              -----------------
<S>                                                           <C>
Real estate, net........................................      $         261,754
Tenant receivables, net.................................                    824
Deferred rent receivable................................                 32,593
Deferred costs, net.....................................                 13,121
Mortgage notes payable..................................               (205,109)
Accrued real estate taxes...............................                 (9,721)
                                                              -----------------
Net assets sold.........................................                 93,462
Proceeds from sales of real estate......................                150,121
                                                              -----------------
Total gain on sales of real estate......................                 56,659
Less gain deferred......................................                 (4,177)
                                                              -----------------
Gain recognized on sales of real estate.................      $          52,482
                                                              =================
</TABLE>

                                      -7-
<PAGE>
                            PRIME GROUP REALTY TRUST
                   Notes to Consolidated Financial Statements
                                   (Unaudited)

1.   BASIS OF PRESENTATION

The accompanying  unaudited  consolidated and combined financial statements have
been prepared in accordance with generally  accepted  accounting  principles for
interim financial information and with the instructions to Form 10-Q and Article
10 of Regulation  S-X.  Accordingly,  they do not include all of the information
and footnotes required by generally accepted accounting  principles for complete
financial statements. In the opinion of management,  all adjustments (consisting
of normal recurring accruals)  considered necessary for a fair presentation have
been included.  Operating  results for the nine-month period ended September 30,
1999 are not necessarily  indicative of the results that may be expected for the
year ended December 31, 1999. For further information, refer to the consolidated
financial  statements  and  footnotes  thereto  included in Prime  Group  Realty
Trust's annual report on Form 10-K for the year ended December 31, 1998 as filed
with the Securities and Exchange Commission on March 31, 1999 ("Form 10-K").

Certain prior period  amounts have been  reclassified  to conform to the current
financial statement presentation.

2.   FORMATION OF THE COMPANY

Prime Group Realty Trust (the  "Company")  was organized in Maryland on July 21,
1997 to  continue  the  business  of The Prime  Group,  Inc.  and certain of its
affiliates.  The Company  intends to qualify as a real estate  investment  trust
("REIT") under the Internal Revenue Code of 1986, as amended, for Federal income
tax purposes.

The Company is the  managing  general  partner of Prime Group  Realty,  L.P.,  a
Delaware limited  partnership (the "Operating  Partnership") and owns all of the
preferred  units  and  58.6%  and  59.4% of the  common  units of the  Operating
Partnership  issued at September  30, 1999 and December 31, 1998,  respectively.
Each  common  unit  entitles  the  Company  to  receive  distributions  from the
Operating  Partnership.  Distributions  declared  or paid to  holders  of common
shares  and  preferred  shares  are based upon such  distributions  the  Company
receives with respect to its common units and preferred units.

3.   INCOME TAXES

Commencing  with the period ended December 31, 1997,  the Company  elected to be
taxed as a REIT under the Internal Revenue Code of 1986, as amended.  As a REIT,
the Company  generally  will not be subject to federal  income tax to the extent
that it distributes at least 95% of its REIT taxable income to its shareholders.
REITs are subject to a number of organizational and operational requirements. If
the Company fails to qualify as a REIT in any taxable year,  the Company will be
subject to federal income tax (including any applicable alternative minimum tax)
on its taxable income at regular corporate tax rates.

4.   USE OF ESTIMATES

The  preparation  of the  financial  statements  in  conformity  with  generally
accepted  accounting  principles  requires  management  to  make  estimates  and
assumptions  that  affect the  reported  amounts of assets and  liabilities  and
disclosure of  contingent  assets and  liabilities  at the date of the financial
statements and the reported amounts of revenue and expenses during the reporting
period. Actual results could differ from these estimates.





                                      -8-
<PAGE>
5. RECENT DEVELOPMENTS

During the period from January 1, 1999 through  September 30, 1999,  the Company
acquired and sold the following office and industrial properties, and parcels of
land (See  "Management's  Discussion  and  Analysis of Financial  Condition  and
Results of Operations-Liquidity and Capital Resources" for a further description
of the debt terms):

<TABLE>
<CAPTION>
                                                                  ACQUISITION
                                                    NET           COST/SALES
                                                 RENTABLE           PRICE           MORTGAGE
                                                 SQ. FT./       (IN MILLIONS)         DEBT              MONTH
     PROPERTY               LOCATION              ACRES              (1)          (IN MILLIONS)     ACQUIRED/SOLD
- -------------------   --------------------   ---------------   ---------------   ---------------   ---------------
<S>                   <C>                    <C>               <C>               <C>               <C>

ACQUIRED:
Office:
  33 West Monroe      Chicago, IL                    846,759    $        101.3   $          65.0        January
    Street (2)
  National City       Cleveland, OH                  766,965             105.0              63.6        February
    Center (3),(4)
  800-810 Jorie       Oak Brook, IL                  190,829              29.5              21.0        August
    Blvd (5)
Industrial:
  901 Technology      Libertyville, IL                68,824               4.1                 -        January
    Way (4),(6)
  300 Craig Place     Hillside, IL                   163,070               8.6               6.5        July
    (7)
  43-47 Hintz Road    Wheeling, IL                   310,156               9.7               6.0        September
    (8)
                                             ---------------   ---------------   ---------------
                                                   2,346,603   $         258.2   $         162.1
                                             ===============   ===============   ===============
Land:
  Carol Stream        Carol Stream, IL
    Land (6),(9)                                  24.1 Acres   $           3.2                 -        April
  Aurora III (10)     Aurora, IL                  13.5 Acres               0.9                 -        July
  300 West Monroe     Chicago, IL                  1.4 Acres              55.9   $          28.0        July
    Street & 25 and
    77 South Wacker
    Drive (11)
                                             ---------------   ---------------   ---------------
  Total Land Acquired                             39.0 Acres   $          60.0   $          28.0
                                             ===============   ===============   ===============

SOLD:
Office:
  941-961 Weigel      Elmhurst, IL                   123,077
     Drive
Industrial:
  300 Craig Place     Hillside, IL                   163,070
  306-310 Era Drive   Northbrook, IL                  36,495
  515 Huehl Road/     Northbrook, IL                 201,244
    500 Lindberg
    Road
  555 Huehl Road      Northbrook, IL                  74,000
  1301 Ridgeview      McHenry, IL                    217,600
    Drive
  3818 Grandville/    Gurnee, IL                     345,232
   1200 Northwestern
  801 Technology Way  Libertyville, IL                68,824
  901 Technology Way  Libertyville, IL                68,824
  1001 Technology     Libertyville, IL               212,831
    Way
                                             ---------------
  Total Office &
   Industrial Sold
    (12),(13)                                      1,511,197   $          89.5   $          63.2        July
                                             ===============   ===============   ===============
Land:
  180 Kehoe Blvd.     Carol Stream, IL             7.5 Acres   $           1.0                 -        July
    (14)
                                             ===============   ===============   ===============

50% of Common Interest:
  77 W. Wacker Drive  Chicago, IL                    944,556          (15)              (15)            September
    (15)
                                             ===============   ===============   ===============
Portion of an Office Property:
  122 S. Michigan     Chicago, IL                    161,710   $          15.0                 -        April
    (16)
                                             ===============   ===============   ===============
</TABLE>

                                      -9-
<PAGE>
(1)  Acquisition  cost includes cash paid at closing plus prorations and accrued
     real estate taxes.

(2)  This  acquisition  was partially  funded by the proceeds of a $65.0 million
     mortgage loan initially  bearing  interest at LIBOR plus 2.0% increasing to
     LIBOR plus 2.15% in 1/2000,  requiring monthly interest only payments,  and
     maturing 1/2002.

(3)  The Company  partially  funded the acquisition  costs with $30.0 million in
     advances  from its credit  facilities  and the  assumption  of two notes of
     $52.9 million and $8.7  million,  with actual  interest  rates of 8.50% and
     7.55%, respectively. These interest rates were in excess of the market rate
     at the acquisition  date,  which we estimated to be 6.75%. As a result,  we
     have  recorded  an  additional  $2.0  million of  principal  to reflect the
     imputed interest rate of 6.75% over the term of the notes.

(4)  These  properties were acquired from minority  interest unit holders of the
     Operating  Partnership  or their  affiliates,  and, in the case of National
     City  Center,  an  affiliate  of the employer of a board member and, in the
     case of 901 Technology Way, an affiliate of an officer of the Company.

(5)  This  acquisition  was funded by the proceeds of a $21.0  million  mortgage
     loan bearing interest at LIBOR plus 2.0%,  requiring  monthly principal and
     interest  payments,  maturing 8/2002 and a portion of the proceeds from the
     sale of the properties  referred to in note 13 below,  as this property was
     identified as a replacement property under the tax-deferred exchange trust.

(6)  Approximately 7.5 acres of the Carol Stream Land (180 Kehoe Blvd.) was sold
     on July 8,  1999 and 901  Technology  Way was sold on July  14,  1999.  See
     descriptions of sold properties for  information  regarding  disposition of
     these parcels.

(7)  This  property  was  purchased  from a board  member who is also a minority
     interest unit holder of the Operating Partnership. The $6.5 million of debt
     was assumed by the Company upon  acquisition  of the property and repaid in
     full upon sale of the property (see note 13 below).

(8)  This acquisition was funded by the proceeds of a $6.0 million mortgage loan
     bearing  interest  at LIBOR plus 2.25%,  requiring  monthly  interest  only
     payments,  maturing  9/2002 and a portion of the proceeds  from the sale of
     the  properties  referred  to in  note  13  below,  as  this  property  was
     identified as a replacement property under the tax-deferred exchange trust.

(9)  This  property was  acquired  from a board  member,  who is also a minority
     interest  unit  holder in the  Operating  Partnership,  for a total of $3.1
     million in common units and $0.1 million in cash. These  acquisitions  were
     consummated  pursuant  to  the  Operating   Partnership's  1998  commitment
     (subsequently extended to 1999) under land purchase obligations established
     at the Company's initial public offering.

(10) The Company has  contracts  that require it to purchase  132.7 acres over a
     three  to five  year  period.  Certain  minimum  installment  payments  are
     required;  however, the timing of purchases is at the Company's discretion.
     This purchase is a part of these contracts.

(11) This  property  was acquired  with two  acquisition  mortgage  loans in the
     amounts of $4.0  million and $24.0  million  and a portion of the  proceeds
     from the sale of the properties in note 13 below. The $4.0 million loan


                                      -10-
<PAGE>
     is  collateralized  by the parcel  located at 25 and 77 South Wacker Drive,
     matures on November 1, 2001, and bears interest at (a) until the funding of
     a construction  loan for the 300 West Monroe Street parcel,  the Prime Rate
     plus 0.5%, and (b)  thereafter at LIBOR plus 2.75% and has been  guaranteed
     by the Operating  Partnership.  The $24.0 million loan is collateralized by
     the adjacent  parcel located at 300 West Monroe  Street,  matures on May 1,
     2000, bears interest at the Prime Rate plus 0.5% and has been guaranteed by
     the Company and the owner of the 25 and 77 South Wacker Drive  parcel.  The
     25 and 77 South Wacker Drive  property  also has been pledged as collateral
     for the $24.0 million loan.  The 25 and 77 South Wacker Drive  property had
     been identified as a replacement  property under the tax-deferred  exchange
     trust discussed in note 13 below.

(12) Mortgage debt represents the amount of debt repaid on or before the sale or
     assumed by the purchaser.  The extraordinary loss on extinguishment of debt
     for the nine  months  ended  September  30,1999  includes  the write off of
     unamortized deferred financing fees of $0.5 million.

(13) These properties were sold in a single transaction with a total sales price
     of $89.5 million,  resulting in a gain of  approximately  $4.2 million.  As
     part of the sale, the Company agreed to assume  responsibility  for leasing
     two of the properties  for five years,  once the existing  tenants'  leases
     expire in 2000 and 2001. The Company's total lease obligation is reduced as
     existing tenants renew their leases or as new leases from third parties are
     executed for space in the properties. As a result of these commitments, the
     gain has been  deferred  and is  included  in other  liabilities  until the
     tenants either renew their leases or are replaced.  The gain may be reduced
     by any obligations the Company may incur as a result of these  commitments.
     In order to defer the taxable gain on this transaction,  net sales proceeds
     of $26.7  million were  deposited at closing into a  tax-deferred  exchange
     trust for reinvestment in future property purchases.

(14) Prime Group Realty Services, Inc., an unconsolidated affiliate, constructed
     an  office/warehouse  facility on this parcel and sold it to the  purchaser
     concurrently with the Company's sale of the land. This affiliate leased the
     land from the  Company  during the  portion of the  construction  period in
     which the Company owned the land.

(15) On  September  30, 1999,  the Company sold a 50% common  interest for $22.0
     million and a $66.0  million  preferred  interest  (providing  a cumulative
     preferred  return of 9.5% per annum) in this  property.  The  remaining 50%
     common   interest  will  be  accounted  for  using  the  equity  method  of
     accounting.  Prior to the closing of the  transaction,  the existing $170.0
     million  non-recourse  first  mortgage  was  refinanced  with a new  $170.0
     million   non-recourse   first   mortgage.   The   extraordinary   loss  on
     extinguishment  of debt  for the  nine  months  ended  September  30,  1999
     includes  the  write off of  unamortized  deferred  financing  fees of $0.9
     million.  The new  mortgage  loan  bears  interest  at  LIBOR  plus  1.25%,
     requiring  interest only  payments  from time to time and annual  principal
     payments, maturing 9/2004. The sale resulted in a gain of $48.5 million for
     the nine months ended September 30, 1999  representing  the net proceeds in
     excess of net book volume as of September 30, 1999.  As a result,  the book
     basis of the  remaining 50% common  interest is $0 for financial  reporting
     purposes.  In order to defer  the  taxable  gain on this  transaction,  net
     proceeds of $84.9 million were deposited into a tax-deferred exchange trust
     for reinvestment in future property purchases.  The Company must identify a
     replacement property or properties within 45 days of this closing and close
     on the  acquisition(s)  within 180 days.  The  Company has  identified  IBM
     Plaza,  an office  building  located in Chicago,  Illinois as a replacement
     property. See further discussion below.


                                      -11-
<PAGE>
(16) On April 19,  1999,  the Company  sold  approximately  161,710 net rentable
     square  feet  of  its  122  South  Michigan   Avenue  office   building  to
     National-Louis  University  (NLU) for a gross sales price of $14.95 million
     and  consideration,  net of  commission,  closing  costs and a $1.1 million
     capital improvement allowance,  of $12.1 million. As part of this sale, NLU
     has also acquired an undivided  31.56%  interest in certain common areas of
     the  property.  The  Company  continues  to own the  remaining  350,659 net
     rentable  square feet of the building and is responsible for the management
     of the entire property. The sale resulted in a gain of $4.0 million for the
     nine months ended September 30, 1999.

On July 22,  1998,  the  Company  entered  into a  purchase  agreement,  with an
affiliate of an investor in the  Operating  Partnership  and an affiliate of the
employer  of a board  member  to  acquire  two  office  buildings,  IBM Plaza (a
1,354,354  square foot office building  located in the Chicago central  business
district) and National City Center in Cleveland,  Ohio for an aggregate purchase
price of approximately  $357.0 million. On February 4, 1999, the Company entered
into an amended  option  agreement  with the sellers of IBM Plaza and an amended
purchase  agreement  with the sellers of National  City Center (see above).  The
option allowed the Company to purchase IBM Plaza for $238.0  million  (including
an $8.0 million  non-refundable  option  payment) plus  reimbursement  of tenant
improvements and leasing  commissions  expended for new tenants executing leases
after February 15, 1999. On September 30, 1999, the Company exercised its option
to acquire IBM Plaza and intends to close on the  purchase  before  December 20,
1999, the outside  closing date under the amended option  agreement.  Concurrent
with the exercise of its option,  the Company paid a $3.5 million  earnest money
deposit  into a joint order  escrow and funded $0.9  million to the seller for a
portion of a tenant  improvement  allowance provided to an affiliated company in
connection  with the  affiliate's  leasing of 30,314 square feet of space in IBM
Plaza.  This  property  was  identified  as a  replacement  property  under  the
tax-deferred  exchange trust discussed in note 15 above and its purchase will be
partially funded from the sale proceeds.

On February  8, 1999,  the Company  signed a contract  with a buyer  pursuant to
which  the  Company  will  construct  and  sell to the  buyer  an  approximately
1,032-space parking garage,  including approximately 4,000 square feet of retail
space,  on  approximately  22,000  square feet of a 61,302 square foot parcel of
land that the Company owns in the Chicago central business district (see Note 11
regarding  acquisition of this parcel).  The sales price of the completed garage
is  expected to be  approximately  $36.0  million,  plus the value of any of the
retail  space leased by the Company at the time of sale up to a maximum of $1.75
million.  In  addition,  the Company is entitled to receive an  additional  $1.0
million from the buyer if, within 15 years after the sale of the parking  garage
to the buyer,  the Company  substantially  completes  construction  of an office
building on the land  containing at least  800,000  square feet of office space,
which is occupied by at least one tenant who is not affiliated with the Company.
The Company intends to construct an office  building on the land,  which it will
lease to third  parties.  The land parcel for the office  building  could not be
obtained  without  obtaining  the land for the  parking  garage  and in order to
construct  an office  building,  parking  must be  provided  pursuant to current
zoning requirements.

In March 1999, the option period for a parcel adjacent to one of our development
property  sites  lapsed.  The Company has  recorded  the related  non-refundable
option  price  of  $0.6  million  as a loss on land  development  option  in the
consolidated statement of income for the nine months ended September 30, 1999.

On March  1,  1999,  the  Company  terminated  a $160.0  million  treasury  lock
agreement  due to  changes  in terms  and  timing of the  purchase  of an office
building  as a  result  of an  amended  purchase  agreement.  This  resulted  in
approximately  $0.6 million on deposit  related to the treasury  lock  agreement
being  forfeited  at the  time of  termination.  On May 11,  1999,  the  Company
terminated a $170.0 million  treasury lock agreement due to changes in timing of


                                      -12-
<PAGE>
a planned future  securitization of a currently  outstanding $170.0 million loan
related to the 77 West Wacker Drive building.  The termination resulted in a net
settlement  and gain  upon  termination  of $1.2  million.  The net gain of $0.6
million  from  the two  terminations  has been  included  as a net gain in other
income in the statement of income for the nine months ended  September 30, 1999.
During the nine months ended  September 30, 1999, the Company  received net cash
settlements  of  approximately  $15.2  million  related  to both  treasury  lock
agreements.


On April 13,  1999,  the Company  modified the terms of the  Company's  Series A
preferred  shares.  Under  the  original  terms,  the  holders  of the  Series A
preferred shares had certain  conversion rights if for two consecutive  quarters
(1) the ratio of the Company's debt plus nonconvertible preferred shares divided
by its  total  market  capitalization  exceeded  65% or (2)  its  fixed  charges
coverage ratio fell below 1.4. The new agreement  eliminates the  debt-to-market
capitalization  covenant.  In  exchange,  the  holders of the Series A preferred
shares were granted the future right to cause the  redemption of their shares at
a price of  $20.00  per  share  upon  120  days'  prior  written  notice,  which
redemption  may occur  during the period  beginning  January 15, 2002 and ending
January 15, 2004.  The Series A preferred  shares will continue to pay an annual
dividend  of $1.50 per share and will  continue  to be  convertible  into common
shares on a one for one basis.  The Company made a $0.4 million one-time payment
as part of this  transaction,  which will be amortized,  using the straight-line
method,  through  January  15,  2002  as a  preferred  dividend.  All  2,000,000
outstanding  shares  of the  Company's  Series  A  preferred  shares  have  been
reclassified to redeemable  equity at their aggregate  redemption price of $40.0
million,  net of the unamortized  transaction fee, in the  consolidated  balance
sheet.

Under the provisions of one of the credit  facilities,  the Company is obligated
to  maintain  interest  rate  contracts  on  a  portion  of  its  variable  rate
indebtedness.  The Company  entered into an interest rate cap agreement in July,
1999 with a  financial  institution  for an original  notional  amount of $150.0
million at 7.0% during the period from July 1 to October 1, 1999. On November 1,
1999 the Company  entered into an interest rate collar  agreement for the period
from November 1, 1999 through  September  30, 2002 with a financial  institution
for an original  notional  amount of $170.0  million . The interest rate ceiling
under the  agreement  is based on a LIBOR  index rate of 7.75% and the  interest
rate floor is based on a LIBOR index rate of 5.62%. This agreement satisfies the
Company's obligation to maintain interest rate contracts under the provisions of
one of the credit facilities.


6.   EARNINGS PER SHARE

The following  table sets forth the  computation of basic and diluted net income
available per weighted-average common share of beneficial interest for the three
months and nine months ended  September 30, 1999 and 1998 (in thousands,  except
share and per share amounts):











                                      -13-
<PAGE>
<TABLE>
<CAPTION>
                                              Three Months Ended             Nine Months Ended
                                                  September 30,                September 30,
                                          --------------------------   ---------------------------
                                              1999           1998          1999           1998
                                          ------------   -----------   ------------   ------------
<S>                                       <C>            <C>           <C>            <C>
Numerator:
Income before gain on sale
 of real estate, minority
 interests, extraordinary
 items, and preferred
 distributions......................      $      9,309   $     9,688   $     27,936   $     22,095
Minority interests..................            (2,595)       (2,704)        (7,734)        (7,022)
Net income allocated to
 preferred distributions............            (3,037)       (2,950)        (9,067)        (4,991)
                                          ------------   -----------   ------------   ------------

Income before gain on sales of real
 estate and extraordinary items.....             3,677         4,034         11,135         10,082
Gain on sales of real estate, net
 of minority interests..............            28,221             -         30,969              -
Extraordinary loss on extinguishment
 of debt, net of minority interests.              (829)            -           (829)          (525)
                                          ------------   -----------   ------------   ------------
Numerator for earnings per share
 - income available to common
 shares.............................       $    31,069   $    4,034    $     41,275   $      9,557
                                          ============   ===========   ============   ============
</TABLE>
<TABLE>
<CAPTION>
                                              Three Months Ended             Nine Months Ended
                                                  September 30,                September 30,
                                          --------------------------   ---------------------------
                                              1999           1998          1999           1998
                                          ------------   -----------   ------------   ------------
<S>                                       <C>            <C>           <C>            <C>
Denominator:
 Denominator for basic earnings
  per share - weighted average
  common shares.....................       15,135,727     15,535,023     15,134,434    14,771,655
  Effect of dilutive securities:
    Employee stock options..........          118,089             -          64,529             -
                                          ------------   -----------   ------------   ------------
 Denominator for diluted earnings
  per share - adjusted weighted
  -average common shares and
  assumed conversions...............        15,253,816    15,535,023     15,198,963    14,771,655
                                          ============   ===========   ============   ============
</TABLE>











                                      -14-
<PAGE>
<TABLE>
<CAPTION>
                                              Three Months Ended             Nine Months Ended
                                                  September 30,                September 30,
                                          --------------------------   ---------------------------
                                              1999           1998          1999           1998
                                          ------------   -----------   ------------   ------------
<S>                                       <C>            <C>           <C>            <C>
Basic earnings available to
 common shares per weighted
 average common shares:
 Income before gain on sales of
  real estate and extraordinary
  items.............................      $       0.24   $      0.26   $       0.74    $      0.69
 Gain on sales of real estate, net
  of minority interests.............              1.86             -           2.04              -
 Extraordinary loss on
  extinguishment of debt, net of
  minority interests................              (.05)            -           (.05)          (.04)
                                          ------------   -----------   ------------   ------------
 Net income available per
  weighted-average common
  share of beneficial
  interest - basic..................      $       2.05   $      0.26   $       2.73   $      0.65
                                          ============   ===========   ============   ============
</TABLE>
<TABLE>
<CAPTION>
                                              Three Months Ended             Nine Months Ended
                                                  September 30,                September 30,
                                          --------------------------   ---------------------------
                                              1999           1998          1999           1998
                                          ------------   -----------   ------------   ------------
<S>                                       <C>            <C>           <C>            <C>
Diluted earnings available
 to common shares per
 weighted average common
 shares:
 Income before gain on
  sales of real estate and
  extraordinary items...............      $       0.24   $      0.26   $       0.73   $       0.69
 Gain on sales of real estate,
  net of minority interests.........              1.85             -           2.04              -
 Extraordinary loss on
  extinguishment of debt,
  net of minority interests.........              (.05)            -           (.05)          (.04)
                                          ------------   -----------   ------------   ------------

 Net income available per
  weighted average common
  share of beneficial
  interest - diluted................      $       2.04   $      0.26   $       2.72   $       0.65
                                          ============   ===========   ============   ============
</TABLE>




                                      -15-
<PAGE>
Options to purchase  1,120,333 of the  Company's  common shares were excluded in
the  computation  of diluted  earnings  available to common shares for the three
months and nine months  ended  September  30, 1999  because the effect  would be
antidilutive.

The  Company  had  10,679,616  and  10,289,245   weighted-average  common  units
outstanding  during  the  three  months  ended  September  30,  1999  and  1998,
respectively, of which 9,441,368 and 9,067,210,  respectively,  may be converted
(on a one for one basis) into common  shares at the option of the unit  holders.
The  Company  had  10,513,243  and  10,273,902   weighted-average  common  units
outstanding   during  the  nine  months  ended  September  30,  1999  and  1998,
respectively, of which 9,421,964 and 9,067,210,  respectively,  may be converted
into common shares at the option of the unit  holders.  The  convertible  common
units were not included in the computation of diluted earnings per share because
the conversion would be antidilutive.

The Company had 2,000,000  Series A  convertible  preferred  shares  outstanding
during the three months and nine months ended  September 30, 1999 and 1998 which
were not included in the  computations of diluted earnings per share because the
conversion would be antidilutive.


7.   SEGMENT REPORTING

The following  summarizes the Company's historical segment operating results for
the  three  months  and  nine  months  ended  September  30,  1999  and 1998 (in
thousands):
<TABLE>
<CAPTION>

                                                    Three months ended September 30, 1999
                                          --------------------------------------------------------
                                                                        Corporate/
                                                                        Operating
                                             Office      Industrial    Partnership       Total
                                          ------------   -----------   ------------   ------------
<S>                                       <C>            <C>           <C>            <C>
Total revenue.......................      $     43,316   $    6,159    $        321   $     49,796
Total expenses......................            24,369        3,553          12,565         40,487
                                          ------------   -----------   ------------   ------------

Income (loss) before minority
  interests, gain on sales of
  real estate and extraordinary
  item..............................            18,947         2,606        (12,244)         9,309
FFO adjustments:
  Real estate depreciation and
    amortization....................             6,547         1,475                         8,022
  Amortization of costs for leases
    assumed.........................               245             -              -            245
  Straight-line rental revenue
    adjustments.....................              (513)         (122)             -           (635)
  Gain on treasury lock termination.                 -             -              -              -
  Net income allocated to
     preferred shareholders.........                 -             -         (3,037)        (3,037)
                                          ------------   -----------   ------------   ------------
Funds from operations                     $     25,226   $     3,959   $    (15,281)  $     13,904
                                          ============   ===========   ============   ============
</TABLE>










                                      -16-
<PAGE>
<TABLE>
<CAPTION>
                                                    Three months ended September 30, 1999
                                          --------------------------------------------------------
                                                                        Corporate/
                                                                        Operating
                                             Office      Industrial    Partnership       Total
                                          ------------   -----------   ------------   ------------
<S>                                       <C>            <C>           <C>            <C>
Total revenue.......................      $     33,475   $     6,497   $      1,279   $     41,251
Total expenses......................            18,395         3,844          9,324         31,563
                                          ------------   -----------   ------------   ------------
Income (loss) before minority
  interests, gain on sales of real
  estate and extraordinary item.....            15,080         2,653         (8,045)         9,688
FFO adjustments:
  Real estate depreciation and
    amortization....................             4,613         1,494              -          6,107
  Amortization of costs for leases
    assumed.........................               286             -              -            286
  Straight line rental revenue
   adjustments......................              (364)         (167)             -           (531)
  Net income allocated to preferred
   shareholders.....................                 -             -         (2,950)        (2,950)
                                          ============   ===========   ============   ============

Funds from operations                     $     19,615   $     3,980   $    (10,995)  $     12,600
                                          ============   ===========   ============   ============

</TABLE>
<TABLE>
<CAPTION>
                                                    Nine months ended September 30, 1999
                                          --------------------------------------------------------
                                                                        Corporate/
                                                                        Operating
                                             Office      Industrial    Partnership       Total
                                          ------------   -----------   ------------   ------------
<S>                                       <C>            <C>           <C>            <C>
Total revenue.......................      $    128,554   $    20,781   $      2,452   $    151,787
Total expenses......................            72,741        12,215         38,895        123,851
                                          ------------   -----------   ------------   ------------

Income (loss) before minority
 interests, gain on sales of real
 estate and extraordinary items.....            55,813         8,566        (36,443)        27,936
FFO adjustments:
  Real estate depreciation
     and amortization...............            18,545          4,898                       23,443
  Amortization of costs for leases
     assumed........................               736              -             -            736
  Straight-line rental revenue
    adjustments.....................            (1,589)          (256)            -         (1,845)
  Net gain on treasury lock
    terminations....................                 -              -          (615)          (615)
  Loss on land development option...                 -              -           600            600
  Net income allocated to preferred
    shareholders....................                 -              -        (9,067)        (9,067)
                                          ============   ===========   ============   ============
Funds from operations                     $     73,505   $    13,208   $    (45,525)  $     41,188
                                          ============   ===========   ============   ============

</TABLE>







                                      -17-
<PAGE>
<TABLE>
<CAPTION>
                                                    Nine months ended September 30, 1999
                                          --------------------------------------------------------
                                                                        Corporate/
                                                                        Operating
                                             Office      Industrial    Partnership       Total
                                          ------------   -----------   ------------   ------------
<S>                                       <C>            <C>           <C>            <C>
Total revenue.......................      $     85,516   $    19,185   $      2,225   $    106,926
Total expenses......................            46,719        10,858         27,254         84,831
                                          ------------   -----------   ------------   ------------

Income (loss) before minority
 interests, gain on sales of real
 estate and extraordinary items.....            38,797         8,327        (25,029)        22,095
FFO adjustments:
 Real estate depreciation and
   amortization.....................            12,708         4,247              -         16,955
 Amortization of costs for leases
   assumed..........................               852             -              -            852
 Straight line rental revenue
   adjustments......................              (431)         (622)             -         (1,053)
 Net income allocated to preferred
   shareholders.....................                 -             -         (4,991)        (4,991)
                                          ============   ===========   ============   ============
Funds from operations                     $     51,926   $    11,952   $    (30,020)  $     33,858
                                          ============   ===========   ============   ============
</TABLE>


The  following  summarizes  the  Company's  segment  assets and  activity  as of
September 30, 1999 and December 31, 1998 and for the nine months ended September
30, 1999 and 1998:
<TABLE>
<CAPTION>
                                                    September 30,  December 31,
                                                         1999          1998
                                                    ------------   ------------
<S>                                                 <C>             <C>
Segment assets:
   Office.....................................      $    937,762   $    841,818
   Industrial.................................           151,754        186,817
   Corporate/Operating Partnership............           146,794        135,879
                                                    ------------   ------------
Total consolidated assets                           $  1,236,310   $  1,164,514
                                                    ============   ============
</TABLE>
<TABLE>
<CAPTION>
                                                          Nine Months Ended
                                                            September 30,
                                                    ---------------------------
                                                         1999          1998
                                                    ------------   ------------
<S>                                                 <C>             <C>
Expenditures for real estate:
   Office.....................................      $    267,306   $    279,102
   Industrial.................................            23,358          2,475
   Corporate/Operating Partnership............             8,215            397
                                                    ------------   ------------
Total expenditures for real estate                  $    298,879   $    281,974
                                                    ============   ============

</TABLE>












                                      -18-
<PAGE>
8.   PRO FORMA CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS

The  accompanying  unaudited  Pro Forma  Condensed  Consolidated  Statements  of
Operations  of the  Company  are  presented  as if, at January 1, 1998,  (i) the
Company had completed the 1998 sales of its common shares and Series B preferred
shares and used the net proceeds to acquire  preferred units and common units of
the Operating  Partnership and (ii)the  Operating  Partnership  acquired various
office and  industrial  properties  (eight  properties  acquired in 1998 and six
properties  acquired in 1999) with cash and debt  proceeds.  The  unaudited  Pro
Forma  Condensed  Consolidated  Statements  of  Operations  should  be  read  in
conjunction with the historical  financial statements contained in the Company's
Form 10-K. In management's  opinion,  all  adjustments  necessary to reflect the
effects of the transactions described above have been made.

The unaudited Pro Forma Condensed  Consolidated  Statements of Operations of the
Company are not necessarily  indicative of what the actual results of operations
would have been assuming the  transactions  described  above had occurred at the
dates  indicated  above,  nor do they  purport to present the future  results of
operations of the Company.

<TABLE>
<CAPTION>
                                                          Nine Months Ended
                                                            September 30,
                                                    ---------------------------
                                                         1999          1998
                                                    ------------   ------------
<S>                                                 <C>             <C>
Total revenue (in thousands)..................      $    128,864   $    125,811
                                                    ============   ============

Net income available to common
Shareholders (in thousands)...................      $     10,128   $      7,330
                                                    ============   ============

Earnings per diluted common share.............      $       0.67   $       0.50
                                                    ============   ============
</TABLE>






























                                      -19-
<PAGE>
ITEM 2: MANAGEMENT'S  DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS
        OF OPERATIONS

OVERVIEW

We are a  fully-integrated  real estate company providing  property  management,
leasing,  marketing,  acquisition,  development,  redevelopment,   construction,
finance and other related  services.  We intend to qualify as a REIT for federal
income  tax  purposes.  Through  the  Operating  Partnership,  we own 26  office
properties  containing  an aggregate of  approximately  7.5 million net rentable
square feet, 40 industrial  properties  containing an aggregate of approximately
5.0  million  net  rentable  square  feet,  one retail  center  and one  parking
facility. The properties are located primarily in the Chicago metropolitan area.
In  addition,  we own a mortgage on an office  property  containing  728,406 net
rentable  square feet and a 50% common  equity  interest  in an office  property
containing  944,456 net rentable  square feet. We also own  approximately  248.2
acres of developable land and rights to acquire more than 261.2 additional acres
of  developable  land  which   management   believes  could  be  developed  with
approximately  11.0  million  rentable  square  feet of  additional  office  and
industrial space.

In terms of net rentable square feet, at September 30, 1999, approximately 79.6%
of our office  properties and 85.3% of our industrial  properties are located in
the Chicago  metropolitan  area in prime business  locations within  established
business  communities.  The properties located in the Chicago  metropolitan area
account for  approximately  85.6% of our total  rental and tenant  reimbursement
revenue for the nine months ended  September  30,  1999.  Our  remaining  office
properties are located in the Cleveland, Ohio; Nashville,  Tennessee; Knoxville,
Tennessee;  and  Milwaukee,  Wisconsin  metropolitan  areas,  and our  remaining
industrial  properties are located in the Columbus,  Ohio metropolitan  area. We
intend to continue to invest in the acquisition,  development and  redevelopment
of  office  and  industrial   properties   primarily   located  in  the  Chicago
metropolitan area.

We intend to access multiple  sources of capital to fund future  acquisition and
development  activities.  These capital sources may include  undistributed  cash
flow,  borrowings  under  credit  facilities,  proceeds  from  the  issuance  of
long-term, tax-exempt bonds, joint venture arrangements and other debt or equity
securities  and other  bank  and/or  institutional  borrowings.  There can be no
assurance that any such financing will be obtained.

CAUTIONARY STATEMENTS

The following  discussion and analysis of the consolidated  financial  condition
and results of operations  should be read in conjunction  with our  Consolidated
Financial Statements and Notes thereto contained herein. Statements contained in
"Management's  Discussion  and  Analysis of Financial  Condition  and Results of
Operations,"  including without  limitation the "Year 2000" discussion,  include
certain forward-looking  statements within the meaning of the Private Securities
Litigation  Reform  Act of 1995 which  reflect  management's  current  view with
respect  to  future  events  and  financial  performance.  Such  forward-looking
statements are subject to certain risks and  uncertainties;  including,  but not
limited to, the effects of future events on our financial performance;  the risk
that we may be  unable  to  finance  our  planned  acquisition  and  development
activities;  risks related to the  industrial  and office  industry in which our
properties  compete,  including the potential adverse impact of external factors
such as inflation,  consumer confidence,  unemployment rates and consumer tastes
and preferences;  risks associated with our development activities,  such as the
potential for cost overruns,  delays and lack of predictability  with respect to
the financial returns associated with these development activities;  the risk of
a  potential  increase  in market  interest  rates  from  current  rates;  risks
associated with real estate  ownership,  such as the potential adverse impact of
changes  in the local  economic  climate  on the  revenues  and the value of our
properties;  and risks  associated with the impact of the Year 2000 issue on the
processing of date-sensitive information by our computerized information systems



                                      -20-
<PAGE>
as well as our tenants and  vendors.  Readers are  cautioned  not to place undue
reliance on these forward-looking  statements,  which speak only as of September
30, 1999.

Among the facts about which we have made assumptions are the following:

o    future economic conditions which may impact the demand for office space and
     tenant ability to pay rent, either at current or increased levels;

o    prevailing interest rates;

o    the extent of any inflation on operating expenses;

o    our ability to reduce various expenses as a percentage of revenues;

o    our  continuing  ability to pay amounts due to our  preferred  shareholders
     prior to any distribution to our common shareholders; and

o    the continuing availability of our credit facilities.

In addition,  historical  results and percentage  relationships set forth herein
are not necessarily indicative of future operations.

RESULTS OF OPERATIONS

Comparison  of the Three Months Ended  September  30, 1999,  to the Three Months
Ended September 30, 1998.

In analyzing the operating results for the quarter ended September 30, 1999, the
changes in rental and reimbursable  income,  property operating  expenses,  real
estate taxes and depreciation and amortization  from 1998 are due principally to
the addition of a full three months of operating  results for the six properties
acquired in the second quarter of 1998 and the addition of operating results for
the three properties acquired during the first and third quarters, respectively,
of 1999.

For the three months ended  September 30, 1999,  rental  revenue  increased $4.4
million, or 15.8%, to $32.5 million (including lease termination revenue of $1.0
million), tenant reimbursement income increased $3.1 million, or 33.0%, to $12.6
million,  other revenue increased $0.7 million  (including signage rights income
of  $0.5  million)  to $3.0  million,  or  30.3%,  property  operating  expenses
increased  $3.1 million,  or 35.6%,  to $12.0  million,  real estate tax expense
increased  $0.3  million  or  5.1%,  to  $7.2  million  and   depreciation   and
amortization  increased $2.1 million,  or 32.2%, to $8.7 million in each case as
compared to the three months ended September 30, 1998. These gains are partially
offset by the lack of 2.5 months of operations  for nine  industrial  properties
and one office property sold on July 14, 1999. For the  corresponding 2.5 months
in 1998 these sold properties had revenue of $1.3 million,  tenant reimbursement
income of $0.4 million, property operating expenses of $0.1 million, real estate
tax expense of $0.3 million and  depreciation  and  amortization of $0.2 for the
three months ended September 30, 1999.

Rental  revenue,  tenant  reimbursement  income and other revenue for properties
held in both periods decreased $0.6 million for the three months ended September
30, 1999,  primarily  due to a decrease in  termination  revenue.  Corresponding
property  operating  expenses  decreased  by $1.7  million,  primarily  due to a
reduction in real estate tax expense.  Depreciation and  amortization  increased
$1.1 million for the three  months ended  September  30, 1999  primarily  due to
increased tenant improvement depreciation.

Mortgage note interest income  increased $0.3 million,  or 20.6% to $1.7 million
for the three months  ended  September  30, 1999  compared to the same period in
1998, due to additional advances and accrued interest on the first mortgage note
held encumbering the office property known as 180 North LaSalle.




                                      -21-
<PAGE>
Interest expense  increased $3.3 million,  or 43.1%, to $10.9 million during the
three months ended  September 30, 1999 compared to the same period in 1998.  The
increase  was  principally  due to new  mortgages  obtained  on  certain  of the
properties which were acquired in 1999 and in the fourth quarter of 1998.

General and  administrative  expense  remained  consistent  for the three months
ended September 30, 1999 compared to the same period in 1998.

Gain on sales of real estate  increased $48.1 million for the three months ended
September 30, 1999,  due to the sale of  properties  as more fully  described in
"Notes to Consolidated Financial Statements-Recent Developments."

Income  allocated to minority  interests  increased $19.8 million,  or 732.2% to
$22.5 million for the three months ended  September 30, 1999, due to an increase
in income before minority interests and extraordinary item of $47.7 million,  or
492.8% to $57.4 million.  The increase in income before  minority  interests and
extraordinary item is due to a gain of $48.1 million on the sale of real estate,
and  additional  properties  acquired in 1999 and the fourth quarter of 1998 and
the  effects  they  had  on  the  revenue  and  expenses  described  above.  The
extraordinary  loss  on  extinguishment  of  debt,  net of  minority  interests,
increased $0.8 million for the three months ended September 30, 1999, due to the
write-off of unamortized deferred financing fees related to mortgage debt repaid
upon the sale of  properties as more fully  described in "Notes to  Consolidated
Financial Statements - Recent Developments."

Net income  increased  $27.1  million,  or 388.3% to $34.1 million for the three
months ended September 30, 1999, due to the changes in revenue,  expenses,  gain
on  sales  of  real  estate,   minority  interest  and  extraordinary   loss  on
extinguishment of debt described above.

Comparison of the Nine Months Ended September 30, 1999, to the Nine Months Ended
September 30, 1998.

For the nine  months  ended  September  30,  1999,  the  changes  in rental  and
reimbursable  income,   property  operating  expenses,  real  estate  taxes  and
depreciation and  amortization  from the same period in 1998 are due principally
to a full nine months of operating results for eight properties  acquired in the
first half of 1998 and the additional  operating  results for the three and four
properties acquired during the first and third quarters, respectively, of 1999.

For the nine months ended  September 30, 1999,  rental revenue  increased  $29.3
million, or 42.1%, to $98.8 million (including lease termination revenue of $5.1
million),  tenant  reimbursement  income  increased $11.1 million,  or 39.9%, to
$39.0 million,  other revenue  increased $4.1 million or 80.2%, to $9.2 million,
property operating  expenses increased $12.4 million,  or 60%, to $33.2 million,
real estate tax expense increased $7.3 million, or 38.1%, to $26.4 million,  and
depreciation  and  amortization  increased  $7.2  million,  or  39.6%,  to $25.4
million,  in each case as compared to the nine months ended  September 30, 1998.
These gains are  partially  offset by the lack of 2.5 months of  operations  for
nine  industrial  properties and one office  property sold on July 14, 1999. For
the  corresponding  2.5 months in 1998 these sold properties had revenue of $1.3
million,  tenant  reimbursements  income  of $0.4  million,  property  operating
expenses  of  $0.1  million,  real  estate  tax  expense  of  $0.3  million  and
depreciation and amortization of $0.2 million.  Included in other revenue is the
net gain on the  termination of treasury lock agreements of $0.6 million for the
nine months  ended  September  30,  1999,  due to events  described in "Notes to
Consolidated Financial Statements-Recent Developments."

Rental  revenue,  tenant  reimbursement  income and other revenue for properties
held in both periods  increased $2.5 million for the nine months ended September
30, 1999,  primarily  due to eight  properties  acquired  during the nine months
ended  September  30,  1998,  being owned  during the entire  nine months  ended
September  30,  1999,  and  increased  occupancy  and rental  rates at the other




                                      -22-
<PAGE>
properties. Corresponding property operating expenses decreased $0.4 million and
primarily  due to a  reduction  in real  estate tax  expense.  Depreciation  and
amortization  increased  $2.2  million for the nine months ended  September  30,
1999,  primarily  due to the eight  properties  acquired  during the nine months
ended  September  30,  1998,  being owned  during the entire  nine months  ended
September 30, 1999.

Mortgage note interest income  increased $0.4 million,  or 8.8%, to $4.8 million
for the nine months ended  September  30,  1999,  compared to the same period in
1998, due to the additional advances on the first mortgage note held encumbering
the office property known as 180 North LaSalle.

Interest expense increased $10.7 million,  or 48.6%, to $32.8 million during the
nine months ended  September 30, 1999,  compared to the same period in 1998. The
increase  was  principally  due to new  mortgages  obtained  on  certain  of the
properties which were acquired in 1999 and in the fourth quarter of 1998.

General and administrative expense increased $0.8 million, or 16.5% to
$5.5 million for the nine months ended September 30, 1999,  compared to the same
period in 1998, reflecting costs related to the growth of the Company.

Gain on sale of real estate  increased  $52.5  million for the nine months ended
September  30,  1999,  compared to the same  period in 1998,  due to the sale of
properties  as  more  fully  described  in  "Notes  to  Consolidated   Financial
Statements-Recent Developments."

Income  allocated to minority  interests  increased $22.2 million,  or 316.5% to
$29.2 million for the nine months ended September 30, 1999, compared to the same
period in 1998, due to an increase in income before minority  interests of $58.3
million,  or 264.0% to $80.4  million.  The increase in income  before  minority
interests  and  extraordinary  item  was  principally  due to a net gain of $0.6
million on the termination of two treasury lock agreements,  gain on the sale of
real estate of $52.5 million and additional  properties acquired in 1999 and the
fourth  quarter of 1998 and the effects  they had on the  revenue  and  expenses
described above.

The extraordinary  loss on  extinguishment  of debt, net of minority  interests,
increased $0.8 million for the nine months ended  September 30, 1999, due to the
write-off of unamortized deferred financing fees related to mortgage debt repaid
upon the sale of  properties as more fully  described in "Notes to  Consolidated
Financial Statements Recent Developments."

Net income  increased  $35.8 million,  or 246.0%,  to $50.3 million for the nine
months ended September 30, 1999, compared to the same period in 1998, due to the
changes in revenue,  expenses,  gain on sales of real estate, minority interests
and extraordinary loss on extinguishment of debt described above.

LIQUIDITY AND CAPITAL RESOURCES

     HISTORICAL CASH FLOWS. We had net cash provided by operating  activities of
$65.5 million and $53.7 million for the nine months ended September 30, 1999 and
1998,  respectively.  The $11.8  million  increase is  primarily  due to a $35.8
million  increase in net income,  a $7.2 million  increase in  depreciation  and
amortization  expense,  a $0.6  million  increase  in loss  on land  development
option,  a $0.8  million  increase  in the  equity  in  loss  of  unconsolidated
affiliate, a $22.2 million increase in income allocated to minority interests, a
$14.7  million  decrease in other  assets,  a $0.6  million  decrease in accrued
interest,  and a $2.9 million increase in accrued real estate taxes, offset by a
$52.5 million  increase in gain on sale of real estate,  a $0.6 million increase
in gain on treasury lock terminations,  a $0.3 million increase in extraordinary
items, a $1.6 million increase in interest income and development costs added to
the  mortgage  note  receivable  principal,  a $5.2  million  increase in tenant
receivables, a $0.8 million increase in deferred rent receivable, a $4.6 million
decrease in accounts  payable and accrued  expenses,  a $0.2 million decrease in
liabilities for leases assumed and a $6.6 million decrease in other liabilities.





                                      -23-
<PAGE>
The primary uses of cash for investing  activities  during the nine months ended
September 30, 1999,  included:  (i) costs  associated  with the  development and
construction of four office  buildings and one industrial  facility  aggregating
231,896 square feet and 242,088 square feet, respectively, which are expected to
be  available  for  occupancy  during the fourth  quarter of 1999 or early first
quarter of 2000; (ii) costs  associated with the build-out of tenant space;  and
(iii) costs for pre-development  activities associated with future developments.
We had net cash used in  investing  activities  of $ 230.0  million  and  $335.6
million for the nine months ended September 30, 1999 and 1998, respectively. The
$105.6 million  decrease in net cash used in investing  activities from the nine
months ended  September  30, 1998,  through the nine months ended  September 30,
1999, was primarily due to a $17.7 million  increase in restricted  cash escrows
and a $3.7 million net  repayment of loans from the  services  company,  a $17.0
million  increase in  expenditures  for real estate and  equipment,  principally
related to property  acquisitions  and  development,  offset by a $150.1 million
increase in proceeds from the sales of real estate,  a $10.2 million increase in
advances on the mortgage note receivable and a $3.3 increase in leasing costs.

The primary uses of cash for financing  activities  during the nine months ended
September  30, 1999,  were (i)  principal  repayments  on notes payable of $32.4
million,  (ii) preferred and common stock distributions of $24.3 million,  (iii)
distributions to minority interests (including distributions to limited partners
of the Operating Partnership) of $10.5 million, and (iv) financing costs of $3.8
million.  Such uses were  partially  offset by proceeds  from new  borrowings of
$184.3  million  and  $15.3  million  of  deposits  returned  on  treasury  lock
agreements.  We had net cash provided by financing  activities of $128.2 million
and $278.1  million  for the nine  months  ended  September  30,  1999 and 1998,
respectively.  The $149.9  million  decrease in net cash  provided by  financing
activities  from the nine months  ended  September  30,  1998,  through the nine
months ended  September 30, 1999,  was due to, (i) a $15.7  million  decrease in
financing costs, (ii) a $15.3 million increase in deposits recovered on treasury
lock agreements, (iii) $35.9 million in net proceeds from the credit facilities,
(iv) a $56.2 million decrease in the repayment of mortgage notes payable, offset
by a $123.0 million decrease in proceeds from mortgage notes payable, (v) a $1.0
million decrease in contributions from minority interests,  (vi) a $94.4 million
decrease in net  proceeds  from the sale of Series B preferred  shares,  a $47.2
million  decrease in net  proceeds  from a private  placement  and (vii) a $11.1
million increase in distributions to preferred shareholders, common shareholders
and minority interests.

     LIQUIDITY.  Net cash provided from operations represents the primary source
of liquidity to fund distributions, debt service and recurring capital costs. In
order to qualify as a REIT for federal income tax purposes,  we must  distribute
95% of our taxable income (excluding  capital gains) annually.  Accordingly,  we
currently intend to continue to make, but are not  contractually  bound to make,
regular  quarterly  distributions to holders of our common  shares/units and our
preferred  shares.  We have established  annual  distribution  rates as follows:
$1.35 per annum per common share/unit, 7.5% per annum ($1.50 per share) for each
Series A  preferred  share and 9% per annum  ($2.25 per share) for each Series B
preferred share.

     CREDIT FACILITIES. Our credit facilities,  with a maximum loan availability
totaling  $85.0 million as of September 30, 1999,  have been provided by various
financial  institutions,  and are  collateralized  by first mortgages on certain
properties  owned by the Operating  Partnership.  Subject to our compliance with
the  applicable  loan  covenants,  the credit  facilities may be used to provide
funds for acquisitions and development activities and to provide the replacement
letters of credit for our $26.9 million of tax-exempt bonds. As of September 30,
1999, $15.6 million was drawn on credit facilities and $26.9 million was used to
provide  letters of credit for our  tax-exempt  bonds,  leaving an  aggregate of
$42.5 million unused.  Effective  October 22, 1999, we amended one of the credit
facilities,  reducing  its  maximum  loan  availability  to  $35.0  million  and
effective November 5, 1999, we amended the other credit facility, increasing its
maximum  loan  availability  by $2.0  million,  concurrent  with  an  additional
borrowing  of  $2.0  million.   These   amendments   reduced  the  maximum  loan
availability to $47.0 million.


                                      -24-
<PAGE>
     PROPERTY  SALES.  On April 19,  1999,  we sold  approximately  161,710  net
rentable square feet of our 122 South Michigan Avenue office building to NLU for
a gross sales  price of $14.95  million and  consideration,  net of  commission,
closing costs and a capital improvement allowance,  of $12.1 million. As part of
this sale,  NLU also  acquired an undivided  31.56%  interest in certain  common
areas of the  property.  We continue to own the  remaining  350,659 net rentable
square feet of the building and are responsible for the management of the entire
property.  The sale resulted in a gain of $4.0 million for the nine months ended
September 30, 1999.

On July 8, 1999, we sold approximately 7.5 acres of land to Antunes  Properties,
L.L.C. for a purchase price of $1.0 million. Prime Group Realty Services,  Inc.,
an unconsolidated  affiliate,  constructed an office/warehouse  facility on this
parcel and sold it to Antunes Properties,  L.L.C. This affiliate leased the land
from the  Company  during the  portion of the  construction  period in which the
Company owned the land. In order to defer the taxable gain on this  transaction,
net proceeds of $1.0 million were deposited  into a tax-deferred  exchange trust
for reinvestment in future property purchases.

On July 14, 1999, we sold nine industrial  properties and one office property in
a single  transaction with a total purchase price of $89.5 million.  In order to
defer the taxable gain on this transaction,  net sales proceeds of $26.7 million
were  deposited into a tax-deferred  exchange trust for  reinvestment  in future
property  purchases.  Four  replacement  properties  were  identified  under the
tax-deferred  exchange trust; three of these properties have been acquired as of
September 30, 1999 and we estimate that the  acquisition of the fourth  property
will close in late November or early December, 1999.

On September 30, 1999, we sold a 50% common interest in the 77 West Wacker Drive
property for $22.0 million and a $66.0 million preferred  interest  (providing a
cumulative  preferred return of 9.5% per annum) in this property.  The remaining
50% common interest will be accounted for using the equity method of accounting.
Prior  to  the  closing  of  the   transaction,   the  existing  $170.0  million
non-recourse   first  mortgage  was   refinanced   with  a  new  $170.0  million
non-recourse first mortgage.  The new mortgage loan bears interest at LIBOR plus
1.25%,  requiring  interest only payments from time to time and annual principal
payments,  maturing 9/2004. The sale resulted in a gain of $48.5 million for the
nine months ended September 30, 1999. In order to defer the taxable gain on this
transaction,  net proceeds of $84.9 million were  deposited  into a tax-deferred
exchange trust for reinvestment in future property  purchases.  We must identify
replacement   property  within  45  days  of  this  closing  and  close  on  the
acquisition(s)  within 180 days. We have identified IBM Plaza,  Chicago, IL as a
potential replacement property.

     INDEBTEDNESS.  We have financed a portion of our acquisitions with proceeds
from mortgage notes payable from various financial institutions,  with fixed and
variable  interest rates and maturities  from 1999 through 2013. We believe that
our properties have excess value that may be utilized for additional  borrowings
or debt securitizations.

Under the  provisions  of one of the  credit  facilities,  we are  obligated  to
maintain interest rate contracts on a portion of our variable rate indebtedness.
We entered into an interest  rate cap  agreement in July,  1999 with a financial
institution for an original notional amount of $150.0 million at 7.0% during the
period from July 1 to October 1, 1999.  On November 1, 1999 the Company  entered
into an interest  rate  collar  agreement  for the period from  November 1, 1999
through September 30, 2002 with a financial institution for an original notional
amount of $170.0  million . The  interest  rate ceiling  under the  agreement is
based on a LIBOR index rate of 7.75% and the  interest  rate floor is based on a
LIBOR index rate of 5.62%.  This agreement  satisfies our obligation to maintain
interest rate contracts under the provisions of one of the credit facilities.

                                      -25-
<PAGE>
In connection with our recent acquisitions,  development,  and refinancings,  we
obtained the following new  indebtedness  during the nine months ended September
30, 1999:
<TABLE>
<CAPTION>


                                                             Original Principal
                                                                 Balance (In
                                                                  Millions)                             Maturity
Collateral (1),(2)                        Location                                 Interest Rate          Date
- ---------------------------------------------------------------------------------------------------------------------
<S>                                      <C>                 <C>                 <C>                   <C>
33 West Monroe                           Chicago, IL                $ 65.0          LIBOR + 2.0%             1/02
                                                                                   increasing to
                                                                                   2.15% in 1/00
National City Center (3),(4)             Cleveland, OH                63.6             6.75%                 4/01
122 S. Michigan                          Chicago, IL                  14.0          LIBOR + 3.0%             5/04
National City Center (5)                 Cleveland, OH                10.0          LIBOR + 4.5%             1/00
25 and 77 South Wacker (6)               Chicago, IL                   4.0              (7)                 11/01
300 West Monroe (6)                      Chicago, IL                  24.0       Prime Rate + 0.5%           5/00
Pine Meadows (three one-story buildings) Libertyville, IL
   (6)                                                                (8)        LIBOR + 2.25%               2/01
Pine Meadows (one three-story building)  Libertyville, IL
   (6)                                                                (9)        LIBOR + 2.50%               2/01
2000 USG Drive (6)                       Libertyville, IL
                                                                     (10)        LIBOR + 2.25%               2/01
800-810 Jorie Blvd. (3)                  Oak Brook, IL                21.0       LIBOR + 2.0%                8/02
43-47 Hintz Rd. (3),(6)                  Wheeling,IL                   6.0       LIBOR + 2.25%               9/02
77 W. Wacker Drive (11)                  Chicago, IL                 170.0       LIBOR + 1.25%               9/04

<FN>
(1)  All of the loans are  subject  to  various  financial  and other  operating
     covenants and are  collateralized  by mortgages on the  properties,  unless
     otherwise indicated.

(2)  Interest  is  payable  monthly,  with  principal  due at  maturity,  unless
     otherwise indicated.

(3)  Principal and interest payable monthly through maturity.

(4)  Consists  of two assumed  notes of $52.9  million  and $8.7  million,  with
     actual interest rates of 8.50% and 7.55% respectively. These interest rates
     were in  excess  of the  market  rate at the  acquisition  date,  which  we
     estimated to be 6.75%.  As a result,  we have recorded an  additional  $2.0
     million of principal to reflect the imputed interest rate of 6.75% over the
     term of the notes.

(5)  This  loan is  collateralized  by a pledge of a  portion  of the  ownership
     interests in the entity that owns the property.  At the Company's election,
     the interest rate is either (a) the Prime Rate plus 3.25% or (b) LIBOR plus
     4.5%. A loan modification  agreement  extended the maturity date from 10/99
     to 1/00. Other loan terms remained substantially unchanged.

(6)  These loans have been guaranteed by the Company. The $24.0 million 300 West
     Monroe  loan has also been  guaranteed  by the owner of the 25 and 77 South
     Wacker Drive property, such guaranty is secured by a second mortgage on the
     25 and 77 South Wacker Drive property.  The Pine Meadows and 2000 USG Drive
     loans are  cross-collateralized  and  cross-defaulted.  The 43-47 Hintz Rd.
     loan guaranty is limited to $1.5 million.

(7)  Until the  funding of a  construction  loan  related to the 300 West Monroe
     parcel, the Prime Rate plus 0.5%, and thereafter LIBOR plus 2.75%.

(8)  A $8.7 million construction loan commitment, of which $2.9 million has been
     disbursed as of September 30, 1999.

(9)  A $9.4 million construction loan commitment, of which $2.7 million has been
     disbursed as of September 30, 1999.

(10) A $6.3 million construction loan commitment, of which $4.4 million has been
     disbursed as of September 30, 1999.

(11) Refinancing  of a mortgage loan of equal amount.  The new loan provides for
     annual amortization during the term.
</FN>
</TABLE>

                                      -26-
<PAGE>
     DEBT REPAYMENTS.  Our aggregate  indebtedness was $603.6 million and $593.2
million at September 30, 1999, and December 31, 1998, respectively. At September
30, 1999, such  indebtedness  had a weighted  average  maturity of 7.8 years and
bore  interest  at a  weighted  average  interest  rate of 7.2%  per  annum.  At
September 30, 1999, $308.1 million, or 51.0%, of such indebtedness bore interest
at fixed  rates and $295.5  million,  or 49.0% of such  indebtedness,  including
$74.5 million of tax-exempt bonds, bore interest at variable rates.

In  connection  with  the  sale of nine  industrial  properties  and one  office
property on July 14, 1999,  mortgage debt of $63.2 million was repaid with sales
proceeds, or assumed by the purchaser.

In  connection  with the sale of a 50% common  interest in 77 W. Wacker Drive on
September 30, 1999,  $170.0  million of debt was  transferred  to a newly formed
unconsolidated joint venture.  Therefore, the indebtedness is no longer included
in the Company's consolidated financial statements.

     FUTURE DEBT AND EQUITY OFFERINGS.  We filed a shelf registration  statement
on Form S-3 with the  Securities  and  Exchange  Commission,  which was declared
effective  on June 8, 1999,  to register up to $500.0  million of our equity and
debt  securities  for future sale at prices and on terms to be determined at the
time of offering.

     CAPITAL  IMPROVEMENTS.  Our  properties  require  periodic  investments  of
capital  for  tenant-related  capital  improvements.  During  1998,  our  tenant
improvements  and leasing  commissions  averaged $18.04 per square foot of newly
leased office space,  $3.85 per square foot of renewal leased office space,  and
$4.53 per square foot of newly leased  industrial  space.  Our estimated  annual
cost of recurring tenant  improvements and leasing  commissions is approximately
$8.6 million based upon average  annual square feet for leases  expiring  during
the years  ending  December  31,  1999 and  2000.  Our cost of  general  capital
improvements  to our properties  averages  approximately  $3.0 million  annually
based upon an estimate of $0.26 per square foot.

     LIQUIDITY  REQUIREMENTS.   We  expect  to  meet  our  short-term  liquidity
requirements through net cash provided by operations, additional debt financings
and/or joint ventures,  and refinancings of maturing debt. We expect to meet our
long-term  liquidity  requirements  for the  funding  of  property  development,
property  acquisitions,  tenant  improvements  and other  non-recurring  capital
improvements  through  a  combination  of net cash  from  operations,  long-term
secured and unsecured  indebtedness  (including  our credit  facilities),  joint
ventures,  property  sales  and the  issuance  of  additional  equity  and  debt
securities.  There can be no assurance  that we will be  successful in obtaining
the  required  amount  of funds for  these  items or that the  terms of  capital
raising activities, if any, will be as favorable as we have experienced in prior
periods.  The terms of the credit  facilities  and our  preferred  shares impose
restrictions on our ability to incur indebtedness and issue additional preferred
shares.

FUNDS FROM OPERATIONS

Industry analysts  generally  consider Funds from Operations,  as defined by the
National Association of Real Estate Investment Trusts ("NAREIT"), an alternative
measure of  performance of an equity REIT.  Funds from  Operations is defined by
NAREIT to mean net income (loss)  determined in accordance with GAAP,  excluding
gains  (or  losses)  from  debt  restructuring  and  sales  of  property,   plus
depreciation and  amortization  (other than  amortization of deferred  financing
costs and  depreciation  of non-real  estate  assets) and after  adjustment  for
unconsolidated  partnerships  and joint  ventures.  We believe  that in order to
facilitate a clear understanding of the combined historical operating results of
the Company,  Funds from Operations  should be examined in conjunction  with net
income as presented in the unaudited financial  statements included elsewhere in
this Form 10-Q. The following table represents the unaudited  calculation of our
Funds from  Operations for the three months and nine months ended  September 30,
1999 and 1998:



                                      -27-
<PAGE>
<TABLE>
<CAPTION>
                                                           Three Months Ended             Nine Months Ended
                                                           September 30, 1998            September 30, 1998
                                                     ---------------------------   ---------------------------
(IN THOUSANDS)                                           1999           1998           1999            1998
                                                     ------------   ------------   ------------   ------------
<S>                                                  <C>            <C>            <C>            <C>
Net income allocated to common
 Shareholders.................................       $     31,069   $      4,034   $     41,275   $      9,557
Adjustments to reconcile to Funds from
 Operations:
   Real estate depreciation and amortization..              8,022          6,107         23,443         16,955
   Amortization of costs for leases assumed...                245            286            736            852
   Straight-line rental revenue...............               (635)          (531)        (1,845)        (1,053)
   Gain on sale of real estate................            (48,125)             -        (52,482)             -
   Net gain on treasury lock terminations.....                  -                          (615)             -
   Loss on land development option............                  -              -            600              -
   Minority interests.........................             22,499          2,704         29,247          7,022
   Extraordinary loss.........................                829              -            829            525
                                                     ------------   ------------   ------------   ------------
Funds from Operations (1)                            $     13,904   $     12,600   $     41,188   $     33,858
                                                     ============   ============   ============   ============
</TABLE>


(1)  We compute Funds from Operations in accordance  with standards  established
     by the Board of Governors of NAREIT in its March 1995 White Paper (with the
     exception  that we report rental  revenues on a cash basis (e.g.,  based on
     contractual lease terms),  rather than a straight-line GAAP basis, which we
     believe  results in a more accurate  presentation  of its actual  operating
     activities),  which may differ from the methodology  for calculating  Funds
     from Operations used by other certain office and/or  industrial  REITs and,
     accordingly,  may not be comparable to such other REITs. As a result of our
     reporting  rental  revenues  on  a  contractual  basis,   contractual  rent
     increases may cause  reported Funds from  Operations to increase.  Further,
     Funds from Operations does not represent amounts available for management's
     discretionary use because of needed capital replacement or expansion,  debt
     repayment obligations,  or other commitments and uncertainties.  Funds from
     Operations should not be considered as an alternative to net income (loss),
     as an  indication  of our  performance  or to cash  flows as a  measure  of
     liquidity or the ability to pay dividends or make distributions.


IMPACT OF YEAR 2000

OVERVIEW OF Y2K PROBLEM

The Year 2000 or "Y2K" problem refers to the inability of many existing computer
programs  to properly  recognize  a year that  begins  with "20"  instead of the
familiar "19." If left uncorrected, many computer programs having time-sensitive
software  may  recognize a date using "00" as the year 1900 rather than the year
2000.  The  failure to  accurately  recognize  the year 2000 and other key dates
could result in a variety of problems from day  miscalculation to the failure of
entire systems.


THE YEAR 2000 PROGRAM

In mid 1998,  we formed a Year 2000  committee  for the  purpose  of  creating a
program (the "Program") to identify, understand and address the myriad of issues
associated with the Y2K problem.  Our committee is comprised of  representatives
from senior  management and various  departments  including  accounting,  legal,
operations, and information systems. Due to the wide ranging implications of the
Y2K problem, management decided to carry out the Program in multiple phases over
the remainder of 1999. What follows is a description of the activities that have




                                      -28-
<PAGE>
been or are expected to be  conducted in each phase of the Program,  including a
summary  of the  results  obtained  to date  and a time  table  for  completion.
Although many of the phases of the Program are being carried out simultaneously,
the various phases will be discussed separately.


PHASE ONE - ASSESSING OUR Y2K READINESS

The initial step in assessing our Y2K readiness  consisted of conducting a study
to identify any systems that were date  sensitive and,  accordingly,  could have
potential  Y2K  problems.  The study  included  an  examination  of  information
technology and  non-information  technology systems at our home and area offices
and at our  properties.  The  initial  step  of  identifying  systems  has  been
completed by our information services department, property managers and building
engineers through a combination of physical inspections,  information interviews
with our employees and contact with vendors.

After identifying systems that could have a potential Y2K problem, we determined
which of the systems actually have Y2K issues. Much of the required  information
is within the exclusive control of our vendors and manufacturers,  who are being
contacted   through   standard  form  letters  and  telephone  calls  requesting
information.   Our  property   managers  are  each   responsible  for  gathering
information on the Y2K compliance of specific property  systems.  In addition to
examining our systems for compliance,  we continue to assess the progress of the
Building  Owners and Managers  Association  ("BOMA") and other industry  leaders
that  are  monitoring   the   compliance   efforts  of  the  major  utility  and
telecommunications  companies.  The  following  is a  summary  of the  Phase One
results obtained to date.

BUILDING MANAGEMENT SYSTEMS

We have identified three categories of building  management  systems in which we
have the most exposure to potential Y2K problems. These categories include:

o    Building automation (e.g. energy management, HVAC, fire and life safety)
o    Security card access
o    Elevator

In late 1998, our property staff began gathering data on the equipment in all of
our  buildings.  By the end of the second  quarter of 1999,  a  preliminary  Y2K
compliance study of the building management systems outlined above was completed
for all our buildings. Where necessary, we have made modifications,  upgrades or
replacements to address significant issues identified during the study.


INFORMATION SYSTEMS

We have identified  five categories of information  systems in which we have the
most exposure to potential Y2K Problems. These categories include:

o    Accounting and property management
o    Network operating systems
o    Desktop hardware and software
o    Secondary systems
o    Telecommunication systems


ACCOUNTING AND PROPERTY MANAGEMENT

We  recently  replaced  or  upgraded  our  remaining   accounting  and  property
management systems that were not Y2K compliant.

                                      -29-
<PAGE>

NETWORK OPERATING SYSTEMS

We believe that network operating servers are currently compliant.


DESKTOP SOFTWARE

We have  reviewed  all of our desktop  systems and  software  applications,  and
believe that they are compliant.


SECONDARY INFORMATION SYSTEMS

Our  "secondary"  information  systems  include,  but are not limited to:  human
resources,   fixed-asset  systems,  and  forecasting  modeling  software,  which
provides  projections  on property  returns and other  items.  We also  reviewed
internally  developed  software,  such as our budget program and tenant-services
system. We have reviewed all of our secondary information systems and feel these
systems are Y2K compliant.


TELECOMMUNICATION SYSTEMS

We found that some of our telecommunication  systems were not Y2K compliant.  We
have assessed these systems and, where material,  replaced, modified or upgraded
these systems as appropriate,  with the exception of one property location where
the system will be replaced by the end of 1999.


PHASE TWO - DETERMINING THE COST OF ACHIEVING Y2K READINESS AND IMPLEMENTING THE
Y2K ACTION PLAN

We  initiated  a  comprehensive  corporate  wide plan in  mid-1998 to review our
financial and  operational  systems.  The Company has utilized both internal and
external  resources and operating  equipment  for Year 2000  modifications.  The
total cost of the Y2K project is  estimated  at $0.5 million and is being funded
principally  through  operating  cash flows.  To date,  the Company has incurred
approximately   $0.3  million   related  to  all  phases  of  the  Y2K  project.
Approximately  $0.2  million is  attributed  to the purchase of new software and
operating  equipment,  which has been  capitalized.  The remaining  $0.1 million
relates to repair of hardware and software which has been expensed.

PHASE THREE - ASSESSING OUR RISKS OF NON-COMPLIANCE

We do not  believe  that the  impact of the Y2K  problem  will  have a  material
adverse effect on our financial condition and results of operations. Such belief
is based on our  analysis  of the risks  related to both our own  potential  Y2K
problems  discussed above and our assessment of the Y2K problems of our vendors,
suppliers and customers.


FAILURE OF BUILDING MANAGEMENT SYSTEMS

We  believe  that  the  Y2K  risks  to our  financial  condition  and  operation
associated  with a failure of building  management  systems is immaterial due to
the fact that each of our  properties  has,  for the most  part,  an  individual
building  management system.  Accordingly,  a Y2K problem that is experienced at
one building should have no effect on our other  buildings.  In addition,  based
upon our study results received to date, we believe that we will have sufficient
time to correct those system  problems  within our control before the year 2000.
We have  completed  our analysis and testing and have taken  corrective  action,
where appropriate.





                                      -30-
<PAGE>
In the event we do experience a failure of essential building management systems
at one or more of our buildings,  whether due to a failure of one of our systems
or an interruption of utilities,  management believes that the individual tenant
leases will protect us from claims of  constructive  eviction or other  remedies
that could result in a termination  of lease rights.  It is also our belief that
most of our  leases  eliminate,  limit or  quantify  the  rights  of a tenant to
receive an abatement under such  circumstances.  Although there is always a risk
of claims being brought on a  non-contractual  basis (e.g.  in tort),  it is our
belief that our efforts to identify and solve Y2K problems  will  minimize  such
risk.  We have also  attempted  to allocate  the risk of  non-compliance  to the
vendors and manufacturers of the building  management and information systems by
establishing  standard  riders and addenda to be attached to new  contracts  for
systems using time sensitive data.

FAILURE OF INFORMATION SYSTEMS

Since our major source of income is rental payments under long term leases,  the
failure of key  information  systems is not expected to have a material  adverse
effect on our financial condition and results of operations.  Even if we were to
experience problems with the information  systems, the payment of rent under the
leases would not be excused. In addition, we expect to correct those information
system problems within our control before the year 2000,  thereby  minimizing or
avoiding the increased cost of correcting problems after the fact.

THE Y2K PROBLEMS OF OUR VENDORS

The success of our  business is not closely  tied to the  operations  of any one
manufacturer,  vendor or  supplier.  Accordingly,  if any of our  manufacturers,
vendors or suppliers ceases to conduct business due to Y2K related problems,  we
expect to be able to contract with alternate providers without  experiencing any
material adverse effect on our financial condition and results of operations.

THE Y2K PROBLEMS OF OUR CUSTOMERS

Due to our broad  customer/tenant  base,  the  success  of our  business  is not
closely tied to the success of any particular  tenant.  Accordingly,  we believe
that there should not be a material  adverse  effect on our financial  condition
and results of operations if any one of our tenants  ceases to conduct  business
(and pay rent) due to Y2K related problems.

DOOMSDAY SCENARIO

We are aware that it is  generally  believed  that the world's Y2K  problem,  if
uncorrected,  may result in an  economic  crisis of global  proportions.  We are
unable to determine  whether such  predictions  are true or false.  As mentioned
above,  we expect that the nature of our income  (rent from good credit  tenants
under  long-term  leases)  should  serve  as a  hedge  against  any  short  term
disruptions  of business.  However,  if the doomsday  scenarios  prove true,  we
assume that all companies  (including  ours) will  experience the effects in one
way or another.

PHASE FOUR - DEVELOPING CONTINGENCY PLANS

We have contingency  plans in the event that certain systems fail as a result of
Y2K related  problems.  These  contingency  plans involve,  among other actions,
manual  workarounds,  alternative  vendors/suppliers,   and  adjusting  staffing
strategies.




                                      -31-
<PAGE>
INFLATION

Substantially all of our office and industrial leases require tenants to pay, as
additional  rent, a portion of any  increases in real estate taxes and operating
expenses  over a base  amount.  In addition,  many of the office and  industrial
leases provide for fixed increases in base rent or indexed escalations (based on
the  Consumer  Price  Index or other  measures).  We  believe  that the  expense
reimbursements  and  contractual  rent  increases  described  above will  offset
inflationary increases in expenses, in part.

As of  September  30,  1999,  approximately  $295.5  million of our  outstanding
indebtedness  (including  our credit  facilities)  was  subject to  interest  at
floating  rates,  and future  indebtedness  may also be subject to floating rate
interest.







































                                      -32-
<PAGE>
ITEM 3:       QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK


The  following  table  provides   information  about  our  derivative  financial
instruments  and other  financial  instruments  that are sensitive to changes in
interest  rates.  For our mortgage  notes  receivable,  mortgage  notes payable,
credit  facilities and bonds payable,  the table presents  principal cash flows,
including principal amortization, and related weighted-average interest rates by
expected maturity dates as of September 30, 1999.

<TABLE>
                                             Interest Rate Sensitivity
                                       Principal amount by Expected Maturity
                                               Average Interest Rate
<CAPTION>
                                     1999         2000        2001        2002       2003       Thereafter      Total
                                ----------------------------------------------------------------------------------------
                                                                  (Dollars in Millions)
<S>                             <C>             <C>           <C>         <C>       <C>         <C>
Assets:
   Mortgage notes receivable (1)      -            -           -          -          -         $ 77.1          $ 77.1
     Fixed rate                       -            -           -          -          -            9.64%

Liabilities:
   Mortgage notes payable (2):
     Fixed rate                     $ 1.4        $ 5.7       $62.3      $ 3.8       $4.0       $229.7          $306.9
     Average interest rate            7.18%        7.13%       7.26       7.26%      7.25%        7.25%

     Variable rate                  $  .1        $57.5       $58.3      $91.1        -         $ 14.0          $221.0
     Average interest rate (3)        7.78%        7.78%       7.92%      8.59%      8.38%        8.38%

   Bonds payable (2):
     Variable rate                    -            -          -           -          -         $ 74.5          $ 74.5
     Average interest rate (3)        -            -          -           -          -            5.2%

 Obligations under capital leases:
   Imputed rate                     $ .1         $  .2     $  .2        $  .6       $ .1          -            $  1.2
   Average interest rate             6.90%         6.90%     6.90%        6.69%      4.84%        -

<FN>
(1)  See Note 2 to our  consolidated  financial  statements in our Form 10-K for
     the year ended December 31, 1998, for additional information.

(2)  See Note 4 to our  consolidated  financial  statements in our Form 10-K for
     the year ended December 31, 1998, for additional information. The bonds are
     credit  enhanced with letters of credit  provided under credit  facilities,
     which expire in November 2000 and March 2002.

(3)  Based upon the rates in effect at September 30, 1999, the  weighted-average
     interest rate on our mortgage notes payable,  credit facilities,  and bonds
     payable were 7.4%, 7.4%, and 5.2%,  respectively.  If interest rates on our
     variable rate debt increased by one percentage  point,  our annual interest
     expense would increase by approximately $3.0 million.
</FN>
</TABLE>





                                      -33-
<PAGE>
                           PART II: OTHER INFORMATION

ITEM 1.       LEGAL PROCEEDINGS

No material  developments with respect to legal proceedings  occurred during the
period covered by this quarterly report.

ITEM 2.       CHANGES IN SECURITIES AND USE OF PROCEEDS
                  None.

ITEM 3.       DEFAULTS UPON SENIOR SECURITIES

                  None.

ITEM 4.       SUBMISSION OF MATTERS TO A VOTE OF SECURITY HOLDERS

                  None.

ITEM 5.       OTHER INFORMATION

                  None.

ITEM 6.       EXHIBITS AND REPORTS ON FORM 8-K

(a)               Exhibits:

 Exhibit
 Number                               Description
- --------------------------------------------------------------------------------

3.1  Amendment  No.  25  to  the  Amended  and  Restated  Agreement  of  Limited
     Partnership dated as of July 14, 1999.

3.2  Amendment  No.  26  to  the  Amended  and  Restated  Agreement  of  Limited
     Partnership dated as of July 15, 1999.

3.3  Amendment  No.  27  to  the  Amended  and  Restated  Agreement  of  Limited
     Partnership dated as of August 16, 1999.

3.4  Amendment  No.  28  to  the  Amended  and  Restated  Agreement  of  Limited
     Partnership dated as of September 15, 1999.

3.5  Contribution  Agreement dated as of September 30, 1999 by and between 77 W.
     Wacker Limited Partnership and The State Teachers Retirement System of Ohio
     with attached Amended and Restated Operating Agreement.

3.6  Loan  Agreement  dated as of  September  30,  1999  between 77 West  Wacker
     Limited Partnership  ("Borrower") and Westdeutsche  Immobilienbank ("Agent"
     or "Lender") and  Landesbank  Schleswig-Holstein  ("Lender") and Landesbank
     Saar Girozentrale ("Lender") and DSL Bank ("Lender").

12.1 Computation  of ratios of earnings to combined  fixed charges and preferred
     share distributions.

27.1 Financial Data Schedule

(b)  Reports on Form 8-K:

Form 8-K dated  July 14,  1999,  (filed on July 29,  1999;  File No.  001-13589)
relating to the sale of nine industrial properties and one office property.

Form 8-K dated  July 15,  1999,  (filed on July 29,  1999;  File No.  001-13589)
relating to the purchase of a parcel of land.

Form 8-K  dated  September  30,  1999,  (filed on  October  15,  1999;  File No.
001-13589) relating to the sale of a 50% interest in one property.


                                      -34-
<PAGE>
                                   SIGNATURES


Pursuant  to the  requirements  of the  Securities  Exchange  Act of  1934,  the
Registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned thereunto duly authorized.


                                       PRIME GROUP REALTY TRUST
                                       ------------------------
                                       Registrant





Date:     November 12, 1999             /s/ Richard S. Curto
          -----------------             --------------------
                                        Richard S. Curto
                                        President and Chief Executive Officer





Date:     November 12, 1999            /s/  William M. Karnes
          -----------------            ----------------------
                                       William M. Karnes
                                       Executive Vice President and
                                       Chief Financial Officer


                                      -35-

                    AMENDMENT NO. 25 TO AMENDED AND RESTATED
                        AGREEMENT OF LIMITED PARTNERSHIP
                           OF PRIME GROUP REALTY, L.P.

     This  AMENDMENT  NO.  25 TO  AMENDED  AND  RESTATED  AGREEMENT  OF  LIMITED
PARTNERSHIP OF PRIME GROUP REALTY,  L.P. (this  "Amendment")  is made as of July
14, 1999 by Prime Group Realty Trust,  a Maryland real estate  investment  trust
("PGRT"),  as the  Managing  General  Partner of Prime  Group  Realty,  L.P.,  a
Delaware  limited  partnership (the  "Partnership"),  and on behalf of the other
Partners (as  hereinafter  defined).  Capitalized  terms used but not  otherwise
defined  herein shall have the  meanings  given to such terms in the Amended and
Restated  Agreement  of  Limited  Partnership  of the  Partnership,  dated as of
November 17, 1997, by and among PGRT and the other parties signatory thereto, as
amended thereafter (as so amended, the "Limited Partnership Agreement").

                              W I T N E S S E T H:

     WHEREAS,  pursuant to Section 4.3.C. of the Limited Partnership  Agreement,
the Managing  General  Partner may raise all or any portion of Additional  Funds
required by the  Partnership  for the  acquisition  of additional  properties by
accepting  additional  Capital  Contributions,  including the issuance of Common
Units for  Capital  Contributions  that  consist of  property  or  interests  in
property;

     WHEREAS,  pursuant to that Contribution Agreement,  dated as of October 20,
1997, by and among The Prime Group, Inc., an Illinois  corporation,  Prime Group
Realty Trust, a Maryland real estate investment trust, Prime Group Realty, L.P.,
a  Delaware  limited   partnership  and  the  Contributors  named  therein  (the
"Agreement"),  the  Partnership  agreed to purchase  one  property in  Hillside,
Illinois (the "Property")upon the fulfillment of certain conditions;

     WHEREAS,  the  conditions  of the  Agreement  having  been  fulfilled,  the
Partnership  is  acquiring  the  Property in return for issuing  Common Units of
Limited Partner Interest to The Nardi Group, L.L.C.; and

     WHEREAS,  Sections  2.4  and  12.3  of the  Limited  Partnership  Agreement
authorize,  among other things, the Managing General Partner, as true and lawful
agent and attorney-in fact, to execute, swear to, acknowledge, deliver, file and
record this  Amendment  on behalf of each  Partner that has executed the Limited
Partnership Agreement and on behalf of the Partnership.

     NOW,  THEREFORE,  for good and  adequate  consideration,  the  receipt  and
sufficiency  of which are  hereby  acknowledged,  the  parties  hereto  agree as
follows:

     Section 1. ACCEPTANCE OF CAPITAL CONTRIBUTION IN EXCHANGE FOR COMMON UNITS.
(a) PGRT, as Managing General Partner and on behalf of the  Partnership,  hereby
accepts from The Nardi Group,  L.L.C.  the grant of all of its right,  title and
interest in the Property,  a legal  description  of which is attached  hereto as
Exhibit 1, as a Capital  Contribution  in exchange  for 120,551  Common Units of
Limited Partner Interest which are hereby issued by the Partnership to The Nardi
Group, L.L.C.  pursuant to Section 4.3.C of the Limited  Partnership  Agreement,
and which are evidenced by Common Unit Certificate No. 48 of the Partnership.

     (b) Each of the Common  Units of  Limited  Partner  Interest  issued to The
Nardi  Group,  L.L.C.  pursuant to this  Section 2 shall have the same terms and
provisions  as the  Common  Units of  Limited  Partner  Interest  issued  by the
Partnership  on  November  17, 1997 except  that the  Exchange  Rights  relating
thereto  may be  exercised  only  after the  first  (1st)  anniversary  of their
issuance (as opposed to November 17, 1998).

                                      -1-
<PAGE>
     Section 2.  AMENDMENT  OF EXHIBIT A TO THE LIMITED  PARTNERSHIP  AGREEMENT.
Exhibit A to the Limited Partnership Agreement is hereby amended and restated to
reflect the  aforementioned  change(s) by deleting Exhibit A attached thereto in
its entirety, and by attaching in lieu thereof a replacement exhibit in the form
of  Exhibit  A  attached  hereto.  From  and  after  the  effectiveness  of this
Amendment,  the amended and restated Exhibit A attached hereto shall be the only
Exhibit A to the Limited Partnership Agreement, unless and until it is hereafter
further amended.

     Section 3. REFERENCE TO AND EFFECT ON THE LIMITED PARTNERSHIP AGREEMENT.

     A. The Limited Partnership  Agreement is hereby deemed to be amended to the
extent necessary to effect the matters contemplated by this Amendment. Except as
specifically provided for hereinabove, the provisions of the Limited Partnership
Agreement shall remain in full force and effect.

     B. The execution,  delivery and  effectiveness  of this Amendment shall not
operate (i) as a waiver of any  provision,  right or  obligation of the Managing
General  Partner,  the other  General  Partner or any Limited  Partner under the
Limited Partnership Agreement except as specifically set forth herein or (ii) as
a waiver or consent to any subsequent action or transaction.

     Section 4.  APPLICABLE LAW. This Amendment shall be construed in accordance
with and  governed by the laws of the State of Delaware,  without  regard to the
principles of conflicts of law.

                            [signature page follows]





































                                      -2-
<PAGE>
                                       AMENDMENT NO. 25 TO AMENDED AND RESTATED
                                       AGREEMENT OF LIMITED PARTNERSHIP OF PRIME
                                       GROUP REALTY, L.P.

     IN WITNESS  WHEREOF,  the parties hereto have executed this Amendment as of
the date first written above.

                                       MANAGING GENERAL PARTNER:
                                       -------------------------

                                       PRIME GROUP REALTY TRUST, a
                                       Maryland real estate investment trust

                                       By:   /s/ Jeffrey A. Patterson
                                            ------------------------------------
                                       Name:     Jeffrey A. Patterson
                                             -----------------------------------
                                       Title:  Executive Vice President
                                             -----------------------------------

                                       LIMITED PARTNERS:
                                       -----------------

                                       Each Limited Partner hereby executes
                                       this Amendment to the Limited Partnership
                                       Agreement.

                                       By:  PRIME GROUP REALTY TRUST, a
                                            Maryland real estate investment
                                            trust, as attorney-in fact

                                            By:  /s/ Jeffrey A. Patterson
                                               ---------------------------------

                                            Name:    Jeffrey A. Patterson
                                                 -------------------------------

                                            Title: Executive Vice President
                                                  ------------------------------

                                      -3-
<PAGE>
As to Section 1 hereof,

ACKNOWLEDGED AND AGREED:

THE NARDI GROUP, L.L.C., a
Delaware limited liability company


By:  /s/ Stephen J. Nardi
   -------------------------------
Name:  Stephen J. Nardi
      ----------------------------
Title:  President & CEO
      ----------------------------








                                      -4-
<PAGE>
                                   EXHIBIT A*

               Partners, Number of Units and Capital Contributions

                                        Number of               Capital
Managing General Partner               Common Units          Contribution
- ------------------------               ------------          ------------
                                                             **
Prime Group Realty Trust                15,136,488
    77 West Wacker Drive
    Suite 3900
    Chicago, IL  60601
    Attn:  Richard S. Curto
           James F. Hoffman

General Partner
- ---------------
                                           927,100           $  18,542,000
The Nardi Group, L.L.C.
    c/o Stephen J. Nardi
    4100 Madison Street
    Hillside, IL  60162

Limited Partners
- ----------------

The Nardi Group, L.L.C.                    328,182           $   4,906,061
    c/o Stephen J. Nardi
    4100 Madison Street
    Hillside, IL  60162

Edward S. Hadesman                         388,677           $   7,773,540
Trust Dated May 22, 1992
    c/o Edward S. Hadesman
    2500 North Lakeview
    Unit 1401
    Chicago, IL  60614

Grandville/Northwestern                      9,750           $     195,000
Management Corporation
    c/o Edward S. Hadesman
    2500 North Lakeview
    Unit 1401
    Chicago, IL  60614


- ---------------------------------------
*  As amended by Amendment No. 25 to the Amended and Restated Agreement of
   Limited Partnership of Prime Group Realty, L.P.

** This amount shall be inserted by the Managing General Partner.













                                      -5-
<PAGE>
                               EXHIBIT A - CONT'D

               Partners, Number of Units and Capital Contributions

                                        Number of               Capital
Limited Partners (Cont'd)              Common Units          Contribution
- ------------------------               ------------          ------------

Carolyn B. Hadesman                         54,544           $ 1,090,880
Trust Dated May 21, 1992
    c/o Edward S. Hadesman
    2500 North Lakeview
    Unit 1401
    Chicago, IL  60614

Lisa Hadesman 1991 Trust                   169,053           $ 3,381,060
    c/o Edward S. Hadesman
    2500 North Lakeview
    Unit 1401
    Chicago, IL  60614

Cynthia Hadesman 1991 Trust                169,053           $ 3,381,060
    c/o Edward S. Hadesman
    2500 North Lakeview
    Unit 1401
    Chicago, IL  60614

Tucker B. Magid                             33,085           $   661,700
    545 Ridge Road
    Highland Park, IL 60035

Frances S. Shubert                          28,805           $   576,100
    511 Lynn Terrace
    Waukegan, IL  60085

Grandville Road Property, Inc.               7,201           $   144,020
    c/o Ms. Frances S. Shubert
    511 Lynn Terrace
    Waukegan, IL  60085

Sky Harbor Associates                       62,149           $ 1,242,980
    c/o Howard I. Bernstein
    6541 North Kilbourn
    Lincolnwood, IL  60646

Jeffrey A. Patterson                       110,000           $ 2,200,000
    c/o Prime Group Realty Trust
    77 West Wacker Drive
    Suite 3900
    Chicago, IL  60601

Primestone Investment Partners, L.P.     7,944,893           **
    c/o The Prime Group, Inc.
    77 West Wacker Drive
    Suite 3900
    Chicago, IL  60601
    Attn:  Paul A. Roehri



- ---------------------------------------
** This amount shall be inserted by the Managing General Partner.


                                      -6-
<PAGE>
                               EXHIBIT A - CONT'D

               Partners, Number of Units and Capital Contributions

                                        Number of               Capital
Limited Partners (Cont'd)              Common Units          Contribution
- ------------------------               ------------          ------------

Prime Group VI, L.P.                       304,097           $ 6,050,500
    c/o The Prime Group, Inc.
    77 West Wacker Drive
    Suite 3900
    Chicago, IL  60601
    Attn:    Michael W. Reshcke
             Robert J. Rudnik

H Group LLC                                108,348           $ 1,600,000
    c/o Heitman Financial Ltd.
    180 N. LaSalle
    Suite 3600
    Chicago, IL  60601
    Attn:  Norman Perlmutter

Ray R. Grinvalds                             5,216           $   104,320
    217 Deer Valley Drive
    Barrington, IL  60010

Warren H. John, as Trustee of the
  Warren H. John                            37,259           $   745,180
Trust dated December 18, 1998
    1730 N. Clark Street
    Chicago, IL  60614



                                          Number of                Capital
Managing General Partner               Preferred Units           Contribution
- ------------------------               ---------------           ------------

Prime Group Realty Trust                 2,000,000                **
    77 West Wacker Drive                Convertible
    Suite 3900                          Preferred
    Chicago, IL  60601                  Units
    Attn:    Richard S. Curto
             James F. Hoffman

Prime Group Realty Trust                4,000,000                 **/
    77 West Wacker Drive                Series B
    Suite 3900                          Preferred
    Chicago, IL  60601                  Units
    Attn:  Richard S. Curto
           James F. Hoffman





- ---------------------------------------
** This amount shall be inserted by the Managing General Partner.





                                      -7-
<PAGE>
                         ACKNOWLEDGMENT AND AGREEMENT BY
                           ADDITIONAL LIMITED PARTNER

Prime Group Realty Trust
77 West Wacker Drive
Suite 3900
Chicago, Illinois 60601

     Reference is made to that certain Amended and Restated Agreement of Limited
Partnership  of Prime Group  Realty,  L.P.,  dated as of  November  17, 1997 (as
amended, the "Partnership  Agreement").  All terms used as defined terms and not
otherwise  defined  herein  shall  have  the  meaning  ascribed  thereto  in the
Partnership Agreement.  The Partnership is issuing and delivering 120,551 Common
Units to the undersigned in connection with the purchase from the undersigned of
one property in Hillside, Illinois. The undersigned acknowledges and agrees that
it is an express  condition  of the  Partnership  Agreement  that an  Additional
Limited  Partner assume all of the obligations  under the Partnership  Agreement
with respect to the Common Units.

         The undersigned hereby represents,  warrants,  covenants to, and agrees
with, the Partnership, the Managing General Partner and each Limited Partner as
follows:

          (i)  the   undersigned  has  received  and  reviewed  a  copy  of  the
               Partnership Agreement;

          (ii) the undersigned  desires to become an Additional  Limited Partner
               in  the   Partnership  in  accordance   with  the  terms  of  the
               Partnership Agreement;

          (iii)the undersigned,  by execution hereof, accepts and agrees that it
               is bound by all of the terms and  provisions  of the  Partnership
               Agreement, including without limitation the provisions of Section
               2.4 and the  restrictions  on transfer set forth in Article 11 of
               the Partnership Agreement;

          (iv) the  undersigned  assumes all of the obligations of an Additional
               Limited  Partner  pursuant  to  the  Partnership  Agreement  with
               respect to the Common Units issued to the undersigned;

          (v)  the  Partnership  Agreement  shall be binding on and  enforceable
               against the  undersigned as a Limited  Partner in accordance with
               its terms;

          (vi) the undersigned is an "accredited investor" within the meaning of
               Rule 501(a)  promulgated  under the  Securities  Act of 1933,  as
               amended (the "Securities  Act"). The undersigned  understands the
               risks of, and other  considerations  relating to, its acquisition
               of the Common Units. The  undersigned,  by reason of its business
               and  financial   experience,   together  with  the  business  and
               financial  experience of those persons, if any, retained by it to
               represent  or advise it with  respect  to its  investment  in the
               Common  Units,  (i)  has  such  knowledge,   sophistication   and
               experience  in  financial  and  business  matters  and in  making
               investment  decisions  of  this  type,  that  it  is  capable  of
               evaluating  the merits and risks of an investment in Common Units
               of the Partnership and of making an informed investment decision,
               (ii) is capable of  protecting  its own  interests in  connection
               with  its   acquisition   of   Common   Units   or  has   engaged
               representatives   or  advisors  to  assist  the   undersigned  in
               protecting  its interests in connection  with its  acquisition of
               Common Units and (iii) is capable of bearing the economic risk of
               such investment in Common Units.

                                      -8-
<PAGE>
          (vii)The Common Units to be issued to the  undersigned are acquired by
               the  undersigned  for its own account for investment only and not
               with a view to,  or with any  intention  of,  a  distribution  or
               resale  thereof,  in  whole  or in  part,  or  the  grant  of any
               participation  therein  until and  unless  the  Common  Units are
               exchanged for Common  Shares of the Trust  following the one year
               lock-up period applicable to the Common Units, in accordance with
               the Partnership  Agreement.  The undersigned hereby confirms that
               all  documents,  instruments,  records  and books  pertaining  to
               investment  in Common Units of the  Partnership  and requested by
               the  undersigned  have been made  available  or  delivered to the
               undersigned.  The  undersigned  has  had  an  opportunity  to ask
               questions of and receive answers from the Partnership,  or from a
               person or persons acting on the Partnership's behalf,  concerning
               the  Partnership,  the terms and  conditions  of the  transaction
               contemplated  by  this   Acknowledgment  and  Agreement  and  the
               undersigned's  acquisition of Common Units.  The  undersigned has
               relied upon, and is making its investment  decisions solely upon,
               such  information as has been provided to the  undersigned by the
               Partnership,  and the  undersigned  has not relied upon any other
               information,   literature   or  any  oral   communications.   The
               undersigned was not formed for the specific  purpose of acquiring
               an interest in the Partnership.

          (viii) The  undersigned  acknowledges  that (i) the Common Units to be
               issued  to the  undersigned  have not been  registered  under the
               Securities Act or state  securities  laws by reason of a specific
               exemption or exemptions  from  registration  under the Securities
               Act and applicable state securities laws, (ii) the  Partnership's
               reliance on such exemptions is predicated in part on the accuracy
               and  completeness  of the  representations  and warranties of the
               undersigned, (iii) such Common Units, therefore, cannot be resold
               unless  registered  under the Securities Act and applicable state
               securities  laws,  or unless an exemption  from  registration  is
               available,  (iv) there is no public  market for such Common Units
               and  (v)  the  Partnership  has no  obligation  or  intention  to
               register such Common Units for resale under the Securities Act or
               any state  securities  laws or to take any action that would make
               available any exemption  from the  registration  requirements  of
               such laws. The undersigned  hereby  acknowledges  that because of
               the  restrictions  on transfer or assignment of such Common Units
               to be  issued  which  are set  forth in this  Acknowledgment  and
               Agreement and in the Partnership  Agreement,  the undersigned may
               have to bear  the  economic  risk  of the  investment  commitment
               evidenced by this  Acknowledgment  and  Agreement  and any Common
               Units  acquired  as  contemplated  by  this   Acknowledgment  and
               Agreement for an indefinite  period of time,  and that the Common
               Units by their  terms will not be  exchangable  at the request of
               the holder  thereof for Common Shares of the Company prior to the
               first (1st) anniversary of their issuance.

          (ix) The address of the  undersigned's  principal place of business is
               set  forth  below.  The  undersigned  does not  have any  present
               intention  of  becoming  a  resident  of any  country,  state  or
               jurisdiction  other  than the  country  and  state  in which  its
               present principal place of business is sited.








                                      -9-
<PAGE>
     The  undersigned  has duly executed and delivered this  Acknowledgment  and
Agreement by Additional Limited Partner as of the 14th day of July, 1999.

                                        THE NARDI GROUP, L.L.C.
                                        c/o Stephen J. Nardi
                                        4100 Madison Street
                                        Hillsdale, Illinois 60162


                                       Name: /s/ Stephen J. Nardi
                                            ------------------------------------
                                       Its: President & CEO
                                            ------------------------------------

     By acceptance hereof, Prime Group Realty Trust, as Managing General Partner
of the  Partnership,  approves  and accepts the  admittance  of The Nardi Group,
L.L.C., a Delaware limited liability  company,  as an Additional Limited Partner
in Prime Group Realty, L.P., having the number of Common Units set forth above.

                                       PRIME GROUP REALTY TRUST


                                       By: /s/ Jeffrey A. Patterson
                                          --------------------------------------
                                           Name: Jeffrey A. Patterson
                                                 -------------------------------
                                           Its:  Executive Vice President
                                                 -------------------------------
                                           Date: July 14, 1999
                                                 -------------------------------


































                                      -10-

                    AMENDMENT NO. 26 TO AMENDED AND RESTATED
                        AGREEMENT OF LIMITED PARTNERSHIP
                           OF PRIME GROUP REALTY, L.P.

     This  AMENDMENT  NO.  26 TO  AMENDED  AND  RESTATED  AGREEMENT  OF  LIMITED
PARTNERSHIP OF PRIME GROUP REALTY,  L.P. (this  "Amendment")  is made as of July
15, 1999 by Prime Group Realty Trust,  a Maryland real estate  investment  trust
("PGRT"),  as the  Managing  General  Partner of Prime  Group  Realty,  L.P.,  a
Delaware  limited  partnership (the  "Partnership"),  and on behalf of the other
Partners (as  hereinafter  defined).  Capitalized  terms used but not  otherwise
defined  herein shall have the  meanings  given to such terms in the Amended and
Restated  Agreement  of  Limited  Partnership  of the  Partnership,  dated as of
November 17, 1997, by and among PGRT and the other parties signatory thereto, as
amended thereafter (as so amended, the "Limited Partnership Agreement").

                              W I T N E S S E T H:

     WHEREAS,  pursuant to Section 4.3.C. of the Limited Partnership  Agreement,
the Managing  General  Partner may raise all or any portion of Additional  Funds
required by the  Partnership  for the  acquisition  of additional  properties by
accepting  additional  Capital  Contributions,  including the issuance of Common
Units for  Capital  Contributions  that  consist of  property  or  interests  in
property;

     WHEREAS,  pursuant to that certain Exchange  Agreement dated as of December
15,  1997 by and  between H Group  LLC,  a Delaware  limited  liability  company
("HG"), and the Partnership (the "Exchange  Agreement"),  HG agreed, among other
things,  to grant to the  Partnership an option (the "First Option") to exchange
the Underlying Option (as defined in the Exchange  Agreement) for 220,000 Common
Units of Limited Partner Interest  (subject to adjustment  pursuant to the terms
of the Exchange  Agreement),  which grant of the First Option  contemplated  the
transfer  by the  Partnership  to HG of 5,000  Common  Units of Limited  Partner
Interest  on the date  thereof  and,  subject to the terms of the First  Option,
5,000 Common Units of Limited Partner Interest  (subject to adjustment  pursuant
to the terms of the Exchange Agreement) on the 15th day of each month thereafter
(each such transfer a "First Option  Maintenance  Transfer")  for such number of
months set forth in the Exchange Agreement;

     WHEREAS,  the Partnership has agreed to the terms of the grant by HG of the
First Option set forth in the Exchange Agreement and desires to effect the First
Option Maintenance Transfer due on July 15, 1999;

     WHEREAS,  HG was  admitted  to the  Partnership  as an  Additional  Limited
Partner as of December  15,  1997  pursuant  to  Amendment  No. 2 to the Limited
Partnership Agreement;

     WHEREAS, the Partners desire to amend the Limited Partnership  Agreement to
reflect the increase in outstanding  Common Units resulting from the issuance of
Common Units to HG in connection with the First Option Maintenance  Transfer due
on July 15, 1999; and

     WHEREAS,  Sections  2.4  and  12.3  of the  Limited  Partnership  Agreement
authorize,  among other things, the Managing General Partner, as true and lawful
agent and attorney-in fact, to execute, swear to, acknowledge, deliver, file and
record this  Amendment  on behalf of each  Partner that has executed the Limited
Partnership Agreement and on behalf of the Partnership.

     NOW,  THEREFORE,  for good and  adequate  consideration,  the  receipt  and
sufficiency  of which are  hereby  acknowledged,  the  parties  hereto  agree as
follows:

                                      -1-
<PAGE>
     Section 1. ACCEPTANCE OF CAPITAL CONTRIBUTION IN EXCHANGE FOR COMMON UNITS.
(a) PGRT, as Managing General Partner and on behalf of the  Partnership,  hereby
accepts  the grant of the  rights  consisting  of the First  Option  during  the
twentieth  month  of  the  term  of  the  First  Option  from  HG  as a  Capital
Contribution  having a value on the date hereof of  $100,000,  in  exchange  for
6129.0 Common Units of Limited  Partner  Interest which are hereby issued by the
Partnership  to HG  pursuant  to  Section  4.3.C.  of  the  Limited  Partnership
Agreement,  and which are  evidenced  by Common Unit  Certificate  No. 49 of the
Partnership.

     (b) Each of the  Common  Units of  Limited  Partner  Interest  issued to HG
pursuant  to this  Section 1 shall  have the same  terms and  provisions  of the
Common Units of Limited  Partner  Interest issued by the Partnership on November
17, 1997 except that (i) the Exchange Rights  relating  thereto may be exercised
at any time after  December  15, 1999 (as opposed to November 17, 1998) and (ii)
such  Common  Units  of  Limited  Partner   Interest  will  be  subject  to  the
Registration  Rights  Agreement dated as of December 15, 1997 by and among PGRT,
the Partnership and HG as opposed to the Registration  Rights Agreement  entered
into by PGRT and the Partnership on November 17, 1997.

     Section 2.  AMENDMENT  OF EXHIBIT A TO THE LIMITED  PARTNERSHIP  AGREEMENT.
Exhibit A to the Limited Partnership Agreement is hereby amended and restated to
reflect the  aforementioned  change(s) by deleting Exhibit A attached thereto in
its entirety, and by attaching in lieu thereof a replacement exhibit in the form
of  Exhibit  A  attached  hereto.  From  and  after  the  effectiveness  of this
Amendment,  the amended and restated Exhibit A attached hereto shall be the only
Exhibit A to the Limited Partnership Agreement, unless and until it is hereafter
further amended.

     Section 3. REFERENCE TO AND EFFECT ON THE LIMITED PARTNERSHIP AGREEMENT.

     A. The Limited Partnership  Agreement is hereby deemed to be amended to the
extent necessary to effect the matters contemplated by this Amendment. Except as
specifically provided for hereinabove, the provisions of the Limited Partnership
Agreement shall remain in full force and effect.

     B. The execution,  delivery and  effectiveness  of this Amendment shall not
operate (i) as a waiver of any  provision,  right or  obligation of the Managing
General  Partner,  the other  General  Partner or any Limited  Partner under the
Limited Partnership Agreement except as specifically set forth herein or (ii) as
a waiver or consent to any subsequent action or transaction.

     Section 4.  APPLICABLE LAW. This Amendment shall be construed in accordance
with and  governed by the laws of the State of Delaware,  without  regard to the
principles of conflicts of law.

                            [signature page follows]

















                                      -2-
<PAGE>
                                       AMENDMENT NO. 26 TO AMENDED AND RESTATED
                                       AGREEMENT OF LIMITED PARTNERSHIP OF PRIME
                                       GROUP REALTY, L.P.

     IN WITNESS  WHEREOF,  the parties hereto have executed this Amendment as of
the date first written above.

                                       MANAGING GENERAL PARTNER:

                                       PRIME GROUP REALTY TRUST, a
                                       Maryland real estate investment trust


                                       By: /s/ Jeffrey A. Patterson
                                          --------------------------------------

                                       Name: Jeffrey A. Patterson
                                             -----------------------------------

                                       Title: Executive Vice President
                                              ----------------------------------



                                       LIMITED PARTNERS:
                                       -----------------

                                       Each Limited Partner hereby executes this
                                       this Amendment to the Limited Partnership
                                       Agreement.

                                       By:  PRIME GROUP REALTY TRUST, a
                                            Maryland real estate investment
                                            trust, as attorney-in fact


                                            By:  /s/ Jeffrey A. Patterson
                                               ---------------------------------

                                            Name:  Jeffrey A. Patterson
                                                   -----------------------------

                                            Title: Executive Vice President
                                                   -----------------------------


















                                      -3-
<PAGE>
                                   EXHIBIT A*

               Partners, Number of Units and Capital Contributions

                                          Number of                Capital
Managing General Partner                Common Units             Contribution
- ------------------------                ------------             ------------

Prime Group Realty Trust                15,136,488               **
    77 West Wacker Drive
    Suite 3900
    Chicago, IL  60601
    Attn:  Richard S. Curto
           James F. Hoffman

General Partner
- ---------------
                                           927,100               $  18,542,000
The Nardi Group, L.L.C.
    c/o Stephen J. Nardi
    4100 Madison Street
    Hillside, IL  60162

Limited Partners
- ----------------

The Nardi Group, L.L.C.                    328,182               $   4,906,061
    c/o Stephen J. Nardi
    4100 Madison Street
    Hillside, IL  60162

Edward S. Hadesman                         388,677               $   7,773,540
Trust Dated May 22, 1992
    c/o Edward S. Hadesman
    2500 North Lakeview
    Unit 1401
    Chicago, IL  60614

Grandville/Northwestern                      9,750               $     195,000
Management Corporation
    c/o Edward S. Hadesman
    2500 North Lakeview
    Unit 1401
    Chicago, IL  60614

Carolyn B. Hadesman                         54,544               $   1,090,880
Trust Dated May 21, 1992
    c/o Edward S. Hadesman
    2500 North Lakeview
    Unit 1401
    Chicago, IL  60614

Lisa Hadesman 1991 Trust                   169,053               $   3,381,060
    c/o Edward S. Hadesman
    2500 North Lakeview
    Unit 1401
    Chicago, IL  60614


- ---------------------------------------
*  As amended by Amendment No. 26 to the Amendment and Restated Agreement of
   Limited Partnership of Prime Group Realty, L.P.

** This amount shall be inserted by the Managing General Partner.


                                      -4-
<PAGE>
                               EXHIBIT A - CONT'D

               Partners, Number of Units and Capital Contributions

                                          Number of                Capital
Limited Partners (Cont'd)               Common Units             Contribution
- ------------------------                ------------             ------------

Cynthia Hadesman 1991 Trust                169,053               $   3,381,060
    c/o Edward S. Hadesman
    2500 North Lakeview
    Unit 1401
    Chicago, IL  60614

Tucker B. Magid                             33,085               $     661,700
    545 Ridge Road
    Highland Park, IL 60035

Frances S. Shubert                          28,805               $     576,100
    511 Lynn Terrace
    Waukegan, IL  60085

Grandville Road Property, Inc.               7,201               $     144,020
    c/o Ms. Frances S. Shubert
    511 Lynn Terrace
    Waukegan, IL  60085

Sky Harbor Associates                       62,149               $   1,242,980
    c/o Howard I. Bernstein
    6541 North Kilbourn
    Lincolnwood, IL  60646

Jeffrey A. Patterson                       110,000               $   2,200,000
    c/o Prime Group Realty Trust
    77 West Wacker Drive
    Suite 3900
    Chicago, IL  60601

Primestone Investment Partners, L.P.     7,944,893               **
    c/o The Prime Group, Inc.
    77 West Wacker Drive
    Suite 3900
    Chicago, IL  60601
    Attn:  Paul A. Roehri

Prime Group VI, L.P.                       304,097               $   6,050,500
    c/o The Prime Group, Inc.
    77 West Wacker Drive
    Suite 3900
    Chicago, IL  60601
    Attn:    Michael W. Reshcke
             Robert J. Rudnik

H Group LLC                                114,477               $   1,700,000
    c/o Heitman Financial Ltd.
    180 N. LaSalle
    Suite 3600
    Chicago, IL  60601
    Attn:  Norman Perlmutter

- ---------------------------------------
** This amount shall be inserted by the Managing General Partner.


                                      -5-
<PAGE>

                               EXHIBIT A - CONT'D

               Partners, Number of Units and Capital Contributions

                                          Number of                Capital
Limited Partners (Cont'd)               Common Units             Contribution
- ------------------------                ------------             ------------

Ray R. Grinvalds                             5,216               $     104,320
    217 Deer Valley Drive
    Barrington, IL  60010

Warren H. John, as Trustee of the
  Warren H. John                            37,259               $     745,180
Trust dated December 18, 1998
    1730 N. Clark Street
    Chicago, IL  60614


                                          Number of                Capital
Managing General Partner                Preferred Units          Contribution
- ------------------------                ---------------          ------------

Prime Group Realty Trust                  2,000,000                   **
    77 West Wacker Drive                 Convertible
    Suite 3900                           Preferred
    Chicago, IL  60601                   Units
    Attn:  Richard S. Curto
           James F. Hoffman

Prime Group Realty Trust                  4,000,000                   **/
    77 West Wacker Drive                 Series B
    Suite 3900                           Preferred
    Chicago, IL  60601                   Units
    Attn:    Richard S. Curto
             James F. Hoffman





- ---------------------------------------
** This amount shall be inserted by the Managing General Partner.




















                                      -6-

                    AMENDMENT NO. 27 TO AMENDED AND RESTATED
                        AGREEMENT OF LIMITED PARTNERSHIP
                           OF PRIME GROUP REALTY, L.P.

     This  AMENDMENT  NO.  27 TO  AMENDED  AND  RESTATED  AGREEMENT  OF  LIMITED
PARTNERSHIP OF PRIME GROUP REALTY,  L.P. (this "Amendment") is made as of August
16, 1999 by Prime Group Realty Trust,  a Maryland real estate  investment  trust
("PGRT"),  as the  Managing  General  Partner of Prime  Group  Realty,  L.P.,  a
Delaware  limited  partnership (the  "Partnership"),  and on behalf of the other
Partners (as  hereinafter  defined).  Capitalized  terms used but not  otherwise
defined  herein shall have the  meanings  given to such terms in the Amended and
Restated  Agreement  of  Limited  Partnership  of the  Partnership,  dated as of
November 17, 1997, by and among PGRT and the other parties signatory thereto, as
amended thereafter (as so amended, the "Limited Partnership Agreement").


                              W I T N E S S E T H:

     WHEREAS,  pursuant to Section 4.3.C. of the Limited Partnership  Agreement,
the Managing  General  Partner may raise all or any portion of Additional  Funds
required by the  Partnership  for the  acquisition  of additional  properties by
accepting  additional  Capital  Contributions,  including the issuance of Common
Units for  Capital  Contributions  that  consist of  property  or  interests  in
property;

     WHEREAS,  pursuant to that certain Exchange  Agreement dated as of December
15,  1997 by and  between H Group  LLC,  a Delaware  limited  liability  company
("HG"), and the Partnership (the "Exchange  Agreement"),  HG agreed, among other
things,  to grant to the  Partnership an option (the "First Option") to exchange
the Underlying Option (as defined in the Exchange  Agreement) for 220,000 Common
Units of Limited Partner Interest  (subject to adjustment  pursuant to the terms
of the Exchange  Agreement),  which grant of the First Option  contemplated  the
transfer  by the  Partnership  to HG of 5,000  Common  Units of Limited  Partner
Interest  on the date  thereof  and,  subject to the terms of the First  Option,
5,000 Common Units of Limited Partner Interest  (subject to adjustment  pursuant
to the terms of the Exchange Agreement) on the 15th day of each month thereafter
(each such transfer a "First Option  Maintenance  Transfer")  for such number of
months set forth in the Exchange Agreement;

     WHEREAS,  the Partnership has agreed to the terms of the grant by HG of the
First Option set forth in the Exchange Agreement and desires to effect the First
Option Maintenance Transfer due on August 16, 1999;

     WHEREAS,  HG was  admitted  to the  Partnership  as an  Additional  Limited
Partner as of December  15,  1997  pursuant  to  Amendment  No. 2 to the Limited
Partnership Agreement;

     WHEREAS, the Partners desire to amend the Limited Partnership  Agreement to
reflect the increase in outstanding  Common Units resulting from the issuance of
Common Units to HG in connection with the First Option Maintenance  Transfer due
on August 16, 1999; and

     WHEREAS,  Sections  2.4  and  12.3  of the  Limited  Partnership  Agreement
authorize,  among other things, the Managing General Partner, as true and lawful
agent and attorney-in fact, to execute, swear to, acknowledge, deliver, file and
record this  Amendment  on behalf of each  Partner that has executed the Limited
Partnership Agreement and on behalf of the Partnership.




                                      -1-
<PAGE>
     NOW,  THEREFORE,  for good and  adequate  consideration,  the  receipt  and
sufficiency  of which are  hereby  acknowledged,  the  parties  hereto  agree as
follows:

     Section 1. ACCEPTANCE OF CAPITAL CONTRIBUTION IN EXCHANGE FOR COMMON UNITS.
(a) PGRT, as Managing General Partner and on behalf of the  Partnership,  hereby
accepts  the grant of the  rights  consisting  of the First  Option  during  the
twenty-first  month  of the  term  of the  First  Option  from  HG as a  Capital
Contribution  having a value on the date hereof of  $100,000,  in  exchange  for
5,954.0 Common Units of Limited Partner  Interest which are hereby issued by the
Partnership  to HG  pursuant  to  Section  4.3.C.  of  the  Limited  Partnership
Agreement,  and which are  evidenced  by Common Unit  Certificate  No. 50 of the
Partnership.

     (b) Each of the  Common  Units of  Limited  Partner  Interest  issued to HG
pursuant  to this  Section 1 shall  have the same  terms and  provisions  of the
Common Units of Limited  Partner  Interest issued by the Partnership on November
17, 1997 except that (i) the Exchange Rights  relating  thereto may be exercised
at any time after  December  15, 1999 (as opposed to November 17, 1998) and (ii)
such  Common  Units  of  Limited  Partner   Interest  will  be  subject  to  the
Registration  Rights  Agreement dated as of December 15, 1997 by and among PGRT,
the Partnership and HG as opposed to the Registration  Rights Agreement  entered
into by PGRT and the Partnership on November 17, 1997.

     Section 2.  AMENDMENT  OF EXHIBIT A TO THE LIMITED  PARTNERSHIP  AGREEMENT.
Exhibit A to the Limited Partnership Agreement is hereby amended and restated to
reflect the  aforementioned  change(s) by deleting Exhibit A attached thereto in
its entirety, and by attaching in lieu thereof a replacement exhibit in the form
of  Exhibit  A  attached  hereto.  From  and  after  the  effectiveness  of this
Amendment,  the amended and restated Exhibit A attached hereto shall be the only
Exhibit A to the Limited Partnership Agreement, unless and until it is hereafter
further amended.

     Section 3. REFERENCE TO AND EFFECT ON THE LIMITED PARTNERSHIP AGREEMENT.

     A. The Limited Partnership  Agreement is hereby deemed to be amended to the
extent necessary to effect the matters contemplated by this Amendment. Except as
specifically provided for hereinabove, the provisions of the Limited Partnership
Agreement shall remain in full force and effect.

     B. The execution,  delivery and  effectiveness  of this Amendment shall not
operate (i) as a waiver of any  provision,  right or  obligation of the Managing
General  Partner,  the other  General  Partner or any Limited  Partner under the
Limited Partnership Agreement except as specifically set forth herein or (ii) as
a waiver or consent to any subsequent action or transaction.

     Section 4.  Applicable Law. This Amendment shall be construed in accordance
with and  governed by the laws of the State of Delaware,  without  regard to the
principles of conflicts of law.

                            [signature page follows]













                                      -2-
<PAGE>
                                       AMENDMENT NO. 27 TO AMENDED AND RESTATED
                                       AGREEMENT OF LIMITED PARTNERSHIP OF PRIME
                                       GROUP REALTY, L.P.

     IN WITNESS  WHEREOF,  the parties hereto have executed this Amendment as of
the date first written above.

                                       MANAGING GENERAL PARTNER:
                                       -------------------------

                                       PRIME GROUP REALTY TRUST, a
                                       Maryland real estate investment trust


                                       By:   /s/ W. Michael Karnes
                                             -----------------------------------
                                       Name:  W. Michael Karnes
                                             -----------------------------------
                                       Title:  Executive Vice President
                                             -----------------------------------

                                       LIMITED PARTNERS:
                                       -----------------

                                       Each Limited Partner hereby executes this
                                       Amendment to the Limited Partnership
                                       Agreement.

                                       By:  PRIME GROUP REALTY TRUST, a
                                            Maryland real estate investment
                                            trust, as attorney-in fact


                                       By:  /s/ W. Michael Karnes
                                            ------------------------------------
                                       Name: W. Michael Karnes
                                            ------------------------------------
                                      Title: Executive Vice President
                                            ------------------------------------

























                                      -3-
<PAGE>
                                   EXHIBIT A*

               Partners, Number of Units and Capital Contributions

                                         Number of                 Capital
Managing General Partner               Common Units              Contribution
- ------------------------               ------------              ------------

Prime Group Realty Trust                15,136,488               **
    77 West Wacker Drive
    Suite 3900
    Chicago, IL  60601
    Attn:    Richard S. Curto
             James F. Hoffman

General Partner
- ---------------
                                           927,100               $  18,542,000
The Nardi Group, L.L.C.
    c/o Stephen J. Nardi
    4100 Madison Street
    Hillside, IL  60162

Limited Partners
- ----------------

The Nardi Group, L.L.C.                    328,182               $   4,906,061
    c/o Stephen J. Nardi
    4100 Madison Street
    Hillside, IL  60162

Edward S. Hadesman                         388,677               $   7,773,540
Trust Dated May 22, 1992
    c/o Edward S. Hadesman
    2500 North Lakeview
    Unit 1401
    Chicago, IL  60614

Grandville/Northwestern                      9,750               $     195,000
Management Corporation
    c/o Edward S. Hadesman
    2500 North Lakeview
    Unit 1401
    Chicago, IL  60614

Carolyn B. Hadesman                         54,544               $   1,090,880
Trust Dated May 21, 1992
    c/o Edward S. Hadesman
    2500 North Lakeview
    Unit 1401
    Chicago, IL  60614

Lisa Hadesman 1991 Trust                   169,053               $   3,381,060
    c/o Edward S. Hadesman
    2500 North Lakeview
    Unit 1401
    Chicago, IL  60614

- ---------------------------------------
*   As amended by Amendment No. 27 to the Amended and Restated Agreement of
    Limited Partnership of Prime Group Realty, L.P.

**  This amount shall be inserted by the Managing General Partner.

                                      -4-
<PAGE>
                               EXHIBIT A - CONT'D

               Partners, Number of Units and Capital Contributions

                                         Number of                 Capital
Limited Partners (Cont'd)              Common Units              Contribution
- ------------------------               ------------              ------------

Cynthia Hadesman 1991 Trust                169,053               $   3,381,060
    c/o Edward S. Hadesman
    2500 North Lakeview
    Unit 1401
    Chicago, IL  60614

Tucker B. Magid                             33,085               $     661,700
     545 Ridge Road
     Highland Park, IL 60035

Frances S. Shubert                          28,805               $     576,100
    511 Lynn Terrace
    Waukegan, IL  60085

Grandville Road Property, Inc.               7,201               $     144,020
     c/o Ms. Frances S.
     Shubert
     511 Lynn Terrace
     Waukegan, IL  60085

Sky Harbor Associates                       62,149               $   1,242,980
    c/o Howard I. Bernstein
    6541 North Kilbourn
    Lincolnwood, IL  60646

Jeffrey A. Patterson                       110,000               $   2,200,000
    c/o Prime Group Realty Trust
    77 West Wacker Drive
    Suite 3900
    Chicago, IL  60601

Primestone Investment Partners, L.P.     7,944,893                    **
    c/o The Prime Group, Inc.
    77 West Wacker Drive
    Suite 3900
    Chicago, IL  60601
    Attn:  Paul A. Roehri

Prime Group VI, L.P.                       304,097               $   6,050,500
    c/o The Prime Group, Inc.
    77 West Wacker Drive
    Suite 3900
    Chicago, IL  60601
    Attn:    Michael W. Reshcke
             Robert J. Rudnik
H Group LLC                                120,431               $   1,800,000
    c/o Heitman Financial Ltd.
    180 N. LaSalle
    Suite 3600
    Chicago, IL  60601
    Attn:  Norman Perlmutter

- ---------------------------------------
**  This amount shall be inserted by the Managing General Partner.


                                      -5-
<PAGE>
                               EXHIBIT A - CONT'D

               Partners, Number of Units and Capital Contributions

                                         Number of                 Capital
Limited Partners (Cont'd)              Preferred Units           Contribution
- ------------------------               ---------------           ------------

Ray R. Grinvalds                             5,216               $     104,320
    217 Deer Valley Drive
    Barrington, IL  60010

Warren H. John, as Trustee of the
  Warren H. John                            37,259               $     745,180
Trust dated December 18, 1998
    1730 N. Clark Street
    Chicago, IL  60614


                                         Number of                 Capital
Managing General Partner               Common Units              Contribution
- ------------------------               ------------              ------------

Prime Group Realty Trust                 2,000,000                    **
    77 West Wacker Drive                Convertible
    Suite 3900                          Preferred
    Chicago, IL  60601                  Units
    Attn:  Richard S. Curto
           James F. Hoffman

Prime Group Realty Trust                 4,000,000                    **/
    77 West Wacker Drive                Series B
    Suite 3900                          Preferred
    Chicago, IL  60601                  Units
    Attn:    Richard S. Curto
             James F. Hoffman




- ---------------------------------------
**  This amount shall be inserted by the Managing General Partner.






















                                      -6-

                    AMENDMENT NO. 28 TO AMENDED AND RESTATED
                        AGREEMENT OF LIMITED PARTNERSHIP
                           OF PRIME GROUP REALTY, L.P.

     This  AMENDMENT  NO.  28 TO  AMENDED  AND  RESTATED  AGREEMENT  OF  LIMITED
PARTNERSHIP  OF  PRIME  GROUP  REALTY,  L.P.  (this  "Amendment")  is made as of
September  15,  1999 by  Prime  Group  Realty  Trust,  a  Maryland  real  estate
investment  trust  ("PGRT"),  as the  Managing  General  Partner of Prime  Group
Realty, L.P., a Delaware limited partnership (the "Partnership"),  and on behalf
of the other Partners (as hereinafter  defined).  Capitalized terms used but not
otherwise  defined  herein  shall have the  meanings  given to such terms in the
Amended and Restated Agreement of Limited Partnership of the Partnership,  dated
as of  November  17,  1997,  by and among PGRT and the other  parties  signatory
thereto,  as  amended  thereafter  (as  so  amended,  the  "Limited  Partnership
Agreement").

                              W I T N E S S E T H:

     WHEREAS,  pursuant to Section 4.3.C. of the Limited Partnership  Agreement,
the Managing  General  Partner may raise all or any portion of Additional  Funds
required by the  Partnership  for the  acquisition  of additional  properties by
accepting  additional  Capital  Contributions,  including the issuance of Common
Units for  Capital  Contributions  that  consist of  property  or  interests  in
property;

     WHEREAS,  pursuant to that certain Exchange  Agreement dated as of December
15,  1997 by and  between H Group  LLC,  a Delaware  limited  liability  company
("HG"), and the Partnership (the "Exchange  Agreement"),  HG agreed, among other
things,  to grant to the  Partnership an option (the "First Option") to exchange
the Underlying Option (as defined in the Exchange  Agreement) for 220,000 Common
Units of Limited Partner Interest  (subject to adjustment  pursuant to the terms
of the Exchange  Agreement),  which grant of the First Option  contemplated  the
transfer  by the  Partnership  to HG of 5,000  Common  Units of Limited  Partner
Interest  on the date  thereof  and,  subject to the terms of the First  Option,
5,000 Common Units of Limited Partner Interest  (subject to adjustment  pursuant
to the terms of the Exchange Agreement) on the 15th day of each month thereafter
(each such transfer a "First Option  Maintenance  Transfer")  for such number of
months set forth in the Exchange Agreement;

     WHEREAS,  the Partnership has agreed to the terms of the grant by HG of the
First Option set forth in the Exchange Agreement and desires to effect the First
Option Maintenance Transfer due on September 15, 1999;

     WHEREAS,  HG was  admitted  to the  Partnership  as an  Additional  Limited
Partner as of December  15,  1997  pursuant  to  Amendment  No. 2 to the Limited
Partnership Agreement;

     WHEREAS, the Partners desire to amend the Limited Partnership  Agreement to
reflect the increase in outstanding  Common Units resulting from the issuance of
Common Units to HG in connection with the First Option Maintenance  Transfer due
on September 15, 1999; and

     WHEREAS,  Sections  2.4  and  12.3  of the  Limited  Partnership  Agreement
authorize,  among other things, the Managing General Partner, as true and lawful
agent and attorney-in fact, to execute, swear to, acknowledge, deliver, file and
record this  Amendment  on behalf of each  Partner that has executed the Limited
Partnership Agreement and on behalf of the Partnership.




                                      -1-
<PAGE>
     NOW,  THEREFORE,  for good and  adequate  consideration,  the  receipt  and
sufficiency  of which are  hereby  acknowledged,  the  parties  hereto  agree as
follows:

     Section 1. ACCEPTANCE OF CAPITAL CONTRIBUTION IN EXCHANGE FOR COMMON UNITS.
(a) PGRT, as Managing General Partner and on behalf of the  Partnership,  hereby
accepts  the grant of the  rights  consisting  of the First  Option  during  the
twenty-second  month  of the  term of the  First  Option  from  HG as a  Capital
Contribution  having a value on the date hereof of  $100,000,  in  exchange  for
6125.0 Common Units of Limited  Partner  Interest which are hereby issued by the
Partnership  to HG  pursuant  to  Section  4.3.C.  of  the  Limited  Partnership
Agreement,  and which are  evidenced  by Common Unit  Certificate  No. 51 of the
Partnership.

     (b) Each of the  Common  Units of  Limited  Partner  Interest  issued to HG
pursuant  to this  Section 1 shall  have the same  terms and  provisions  of the
Common Units of Limited  Partner  Interest issued by the Partnership on November
17, 1997 except that (i) the Exchange Rights  relating  thereto may be exercised
at any time after  December  15, 1999 (as opposed to November 17, 1998) and (ii)
such  Common  Units  of  Limited  Partner   Interest  will  be  subject  to  the
Registration  Rights  Agreement dated as of December 15, 1997 by and among PGRT,
the Partnership and HG as opposed to the Registration  Rights Agreement  entered
into by PGRT and the Partnership on November 17, 1997.

     Section 2.  AMENDMENT  OF EXHIBIT A TO THE LIMITED  PARTNERSHIP  AGREEMENT.
Exhibit A to the Limited Partnership Agreement is hereby amended and restated to
reflect the  aforementioned  change(s) by deleting Exhibit A attached thereto in
its entirety, and by attaching in lieu thereof a replacement exhibit in the form
of  Exhibit  A  attached  hereto.  From  and  after  the  effectiveness  of this
Amendment,  the amended and restated Exhibit A attached hereto shall be the only
Exhibit A to the Limited Partnership Agreement, unless and until it is hereafter
further amended.

     Section 3. REFERENCE TO AND EFFECT ON THE LIMITED PARTNERSHIP AGREEMENT.

     A. The Limited Partnership  Agreement is hereby deemed to be amended to the
extent necessary to effect the matters contemplated by this Amendment. Except as
specifically provided for hereinabove, the provisions of the Limited Partnership
Agreement shall remain in full force and effect.

                  B. The execution, delivery and effectiveness of this Amendment
shall not operate (i) as a waiver of any  provision,  right or obligation of the
Managing General Partner, the other General Partner or any Limited Partner under
the Limited  Partnership  Agreement  except as specifically  set forth herein or
(ii) as a waiver or consent to any subsequent action or transaction.

     Section 4.  APPLICABLE LAW. This Amendment shall be construed in accordance
with and  governed by the laws of the State of Delaware,  without  regard to the
principles of conflicts of law.















                                      -2-
<PAGE>
                                       AMENDMENT NO. 28 TO AMENDED AND RESTATED
                                       AGREEMENT OF LIMITED PARTNERSHIP OF PRIME
                                       GROUP REALTY, L.P.

     IN WITNESS  WHEREOF,  the parties hereto have executed this Amendment as of
the date first written above.

                                       MANAGING GENERAL PARTNER:
                                       -------------------------

                                       PRIME GROUP REALTY TRUST, a
                                       Maryland real estate investment trust


                                       By: /s/ Jeffrey A. Patterson
                                           -------------------------------------

                                       Name:  Jeffrey A. Patterson
                                              ----------------------------------

                                       Title: Executive Vice President
                                              ----------------------------------


                                       LIMITED PARTNERS:
                                       -----------------

                                       Each Limited Partner hereby executes this
                                       Amendment to the Limited Partnership
                                       Agreement.

                                       By:  PRIME GROUP REALTY TRUST, a
                                            Maryland real estate investment
                                            trust, as attorney-in fact

                                            By:  /s/ Jeffrey A. Patterson
                                                 -------------------------------

                                            Name:  Jeffrey A. Patterson
                                                   -----------------------------

                                            Title: Executive Vice President
                                                   -----------------------------





















                                      -3-
<PAGE>
                                   EXHIBIT A*

               Partners, Number of Units and Capital Contributions

                                         Number of                  Capital
Managing General Partner               Common Units              Contribution
- ------------------------               ------------              ------------

Prime Group Realty Trust                15,136,488                    **
    77 West Wacker Drive
    Suite 3900
    Chicago, IL  60601
    Attn:  Richard S. Curto
           James F. Hoffman

General Partner
- ---------------
                                           927,100               $  18,542,000
The Nardi Group, L.L.C.
    c/o Stephen J. Nardi
    4100 Madison Street
    Hillside, IL  60162

Limited Partners
- ----------------

The Nardi Group, L.L.C.                    328,182               $   4,906,061
    c/o Stephen J. Nardi
    4100 Madison Street
    Hillside, IL  60162

Edward S. Hadesman                         388,677               $   7,773,540
Trust Dated May 22, 1992
    c/o Edward S. Hadesman
    2500 North Lakeview
    Unit 1401
    Chicago, IL  60614

Grandville/Northwestern                      9,750               $     195,000
Management Corporation
    c/o Edward S. Hadesman
    2500 North Lakeview
    Unit 1401
    Chicago, IL  60614

Carolyn B. Hadesman                         54,544               $   1,090,880
Trust Dated May 21, 1992
    c/o Edward S. Hadesman
    2500 North Lakeview
    Unit 1401
    Chicago, IL  60614

Lisa Hadesman 1991 Trust                   169,053               $   3,381,060
    c/o Edward S. Hadesman
    2500 North Lakeview
    Unit 1401
    Chicago, IL  60614

- ---------------------------------------
*   As amended by Amendment No. 28 to the Amended and Restated Agreement of
    Limited Partnership of Prime Group Realty, L.P.

**  This amount shall be inserted by the Managing General Partner.

                                      -4-
<PAGE>
                                   EXHIBIT A - CONT'D

               Partners, Number of Units and Capital Contributions

                                         Number of                  Capital
Limited Partners (Cont'd)              Common Units              Contribution
- ------------------------               ------------              ------------

Cynthia Hadesman 1991 Trust                169,053               $   3,381,060
    c/o Edward S. Hadesman
    2500 North Lakeview
    Unit 1401
    Chicago, IL  60614

Tucker B. Magid                             33,085               $     661,700
    545 Ridge Road
    Highland Park, IL 60035

Frances S. Shubert                          28,805               $     576,100
    511 Lynn Terrace
    Waukegan, IL  60085

Grandville Road Property, Inc.               7,201               $     144,020
c/o Ms. Frances S. Shubert
    511 Lynn Terrace
    Waukegan, IL  60085

Sky Harbor Associates                       62,149               $   1,242,980
    c/o Howard I. Bernstein
    6541 North Kilbourn
    Lincolnwood, IL  60646

Jeffrey A. Patterson                       110,000               $   2,200,000
     c/o Prime Group Realty Trust
     77 West Wacker Drive
     Suite 3900
     Chicago, IL  60601

Primestone Investment Partners, L.P.     7,944,893                       **
    c/o The Prime Group, Inc.
    77 West Wacker Drive
    Suite 3900
    Chicago, IL  60601
    Attn:    Paul A. Roehri

Prime Group VI, L.P.                       304,097               $   6,050,500
    c/o The Prime Group, Inc.
    77 West Wacker Drive
    Suite 3900
    Chicago, IL  60601
    Attn:    Michael W. Reshcke
             Robert J. Rudnik

H Group LLC                                126,556               $   1,900,000
    c/o Heitman Financial Ltd.
    180 N. LaSalle
    Suite 3600
    Chicago, IL  60601
    Attn:  Norman Perlmutter

- ---------------------------------------
**  This amount shall be inserted by the Managing General Partner.


                                      -5-
<PAGE>
                                   EXHIBIT A - CONT'D

               Partners, Number of Units and Capital Contributions

                                         Number of                  Capital
Limited Partners (Cont'd)              Common Units              Contribution
- ------------------------               ------------              ------------

Ray R. Grinvalds                             5,216               $     104,320
    217 Deer Valley Drive
    Barrington, IL  60010

Warren H. John, as Trustee of the
  Warren H. John                            37,259               $     745,180
Trust dated December 18, 1998
    1730 N. Clark Street
    Chicago, IL  60614



                                         Number of                 Capital
Managing General Partner               Preferred Units           Contribution
- ------------------------               ---------------           ------------

Prime Group Realty Trust                  2,000,000                   **
    77 West Wacker Drive                Convertible
    Suite 3900                          Preferred
    Chicago, IL  60601                  Units
    Attn:    Richard S. Curto
             James F. Hoffman

Prime Group Realty Trust                  4,000,000                   **/
    77 West Wacker Drive                Series B
    Suite 3900                          Preferred
    Chicago, IL  60601                  Units
    Attn:    Richard S. Curto
             James F. Hoffman


- ---------------------------------------
**  This amount shall be inserted by the Managing General Partner.























                                      -6-












                             CONTRIBUTION AGREEMENT

                                   Dated as of

                               September 30, 1999

                                 By and Between

                       77 WEST WACKER LIMITED PARTNERSHIP

                                       and

                                       OTR






































<PAGE>
                                TABLE OF CONTENTS
                                -----------------
                                                                            PAGE
                                                                            ----
ARTICLE I DEFINITIONS.....................................................    1
    Section 1.1    Specific Definitions...................................    1
    Section 1.2    Terms Generally........................................    8

ARTICLE II TERMS OF THE TRANSACTION.......................................    8
    Section 2.1    Formation of the Joint Venture.........................    8
    Section 2.2    Deposit................................................    8
    Section 2.3    Cash Contribution to the LLC...........................    8
    Section 2.4    Instruments of Transfer and Conveyance.................    9
    Section 2.5    77 WWLP Contribution...................................    9
    Section 2.6    Debt Financing of Property.............................    9
    Section 2.7    Title Policy...........................................   10
    Section 2.8    Extinguishment of Existing Debt........................   11
    Section 2.9    Distribution to 77 WWLP................................   11

ARTICLE III INSPECTION....................................................   11
    Section 3.1    Due Diligence; Indemnity.  ............................   11
    Section 3.2    Delivery of Property Information by 77 WWLP and Prime..   12
    Section 3.3    Title and Survey.......................................   13
    Section 3.4    Objection Notice.......................................   13
    Section 3.5    Intentionally deleted..................................   14
    Section 3.6    Intentionally deleted..................................   14
    Section 3.7    Tenant Estoppels.......................................   14
    Section 3.8    Air Rights Lease.......................................   15

ARTICLE IV OPERATIONS AND RISK OF LOSS....................................   15
    Section 4.1    Ongoing Operations.....................................   15
    Section 4.2    Damage.................................................   16
    Section 4.3    Condemnation...........................................   17

ARTICLE V CLOSING.........................................................   17
    Section 5.1    Closing................................................   17
    Section 5.2    Conditions to the Parties' Obligations to Close........   17
    Section 5.3    Deliveries by 77 WWLP in Escrow........................   21
    Section 5.4    OTR's Deliveries in Escrow.............................   22
    Section 5.5    LLC's Deliveries in Escrow.............................   23
    Section 5.6    Closing Statements.....................................   23
    Section 5.7    Possession.............................................   23
    Section 5.8    Delivery of Books and Records..........................   23

ARTICLE VI PRORATIONS; COSTS..............................................   24
    Section 6.1    Prorations. ...........................................   24
    Section 6.2    Post-Closing Corrections...............................   26
    Section 6.3    Utilities..............................................   26
    Section 6.4    Service Contracts......................................   26
    Section 6.5    Costs..................................................   26
    Section 6.6    Sales, Transfer, and Documentary Taxes.................   26
    Section 6.7    Utility Deposits.......................................   26
    Section 6.8    Sales Commissions......................................   26
    Section 6.9    Wages.  Intentionally deleted..........................   26
    Section 6.10   Tenant Improvements and Allowances.....................   26

ARTICLE VII REPRESENTATIONS AND WARRANTIES................................   27
    Section 7.1    Representations and Warranties of 77 WWLP..............   27
    Section 7.2    OTR's Representations and Warranties...................   31
    Section 7.3    Survival of Representations and Warranties.............   31




                                      -i-
<PAGE>
                                                                            PAGE
                                                                            ----
ARTICLE VIII DEFAULT AND REMEDIES.........................................   31
    Section 8.1    Default by 77 WWLP.....................................   31
    Section 8.2    OTR's Default..........................................   32
    Section 8.3    Other Expenses.........................................   32

ARTICLE IX INDEMNIFICATION................................................   32
    Section 9.1    Indemnity of 77 WWLP...................................   32
    Section 9.2    LLC's Indemnity........................................   32
    Section 9.3    Procedure..............................................   32
    Section 9.4    Survivability..........................................   32

ARTICLE X MISCELLANEOUS...................................................   33
    Section 10.1   Parties Bound. ........................................   33
    Section 10.2   Headings. .............................................   33
    Section 10.3   Invalidity; No Waiver..................................   33
    Section 10.4   Governing Law. ........................................   33
    Section 10.5   Survival...............................................   33
    Section 10.6   No Third Party Beneficiary.............................   33
    Section 10.7   Entirety and Amendments................................   34
    Section 10.8   Time. .................................................   33
    Section 10.9   Confidentiality........................................   33
    Section 10.10  Attorneys' Fees........................................   34
    Section 10.11  Notices................................................   34
    Section 10.12  Construction...........................................   34
    Section 10.13  Calculation of Time Periods............................   35
    Section 10.14  Information and Audit Cooperation......................   35
    Section 10.15  Execution in Counterparts..............................   35
    Section 10.16  Exculpation............................................   35
    Section 10.17  Further Assurances.....................................   35
    Section 10.18  Bulk Sales.............................................   35
    Section 10.19  Notification of Certain Matters........................   36
    Section 10.20  Termination............................................   36
    Section 10.21  Procedure and Effect of Termination....................   36
    Section 10.22  Remedies Cumulative; Equitable Relief..................   36
    Section 10.23  Waiver of Compliance; Consents.........................   37
    Section 10.24  Intentionally deleted..................................   37
    Section 10.25  Waiver of Jury Trial...................................   37
    Section 10.26  Like Kind Exchange.....................................   37
    Section 10.27  Sprinkler Heads........................................   37
    Section 10.28  Holidays...............................................   38

EXHIBITS
    Exhibit A -    Commission Schedule....................................   39
    Exhibit B-1 -  Description of Property Subject to Appurtenances.......   40
    Exhibit B-2 -  Description of Land....................................   42
    Exhibit C -    Management Agreement...................................   46
    Exhibit D -    Operating Agreement....................................   47
    Exhibit E -    Management Office Furniture & Equipment
                     Furniture List.......................................

APPENDICES
    Appendix 2.2 - Escrow Agreement.......................................   47
    Appendix 2.6 - Loan Terms.............................................   50
    Appendix 2.7(1) - Reinsurers of Title Policy..........................   51
    Appendix 2.7(2) - Owner's Policy......................................
    Appendix 2.7(3) - Conditions Precedent to Title Policy
                        Performable by 77 WWLP............................   52
    Appendix 3.2 - Description of Property Information....................   54
    Appendix 3.4 - Delinquent Tax Letter Agreement .......................   55
    Appendix 3.7 - Tenant Estoppels.......................................   56


                                     -ii-
<PAGE>
                                                                            PAGE
                                                                            ----
APPENDICES (CONT'D)
    Appendix 3.8 - Ground Lessor Estoppel.................................
    Appendix 5.3(b) - Form of Deed........................................   57
    Appendix 5.3(c) - Form of Bill of Sale and Assignment.................   62
    Appendix 5.3(d) - Tenant and Vendor Notices...........................   70
    Appendix 5.3(f) - Form of FIRPTA Affidavit............................   72
    Appendix 6.1(e) - Leasing Commissions Payable by 77 WWLP..............   74
    Appendix 6.10(a)- 77 WWLP TI Obligations..............................   75
    Appendix 6.10(b)- LLC TI Obligations..................................   76
    Appendix 7.1(c) - Lease Defaults......................................   77
    Appendix 7.1(o) - Litigation..........................................   78
    Appendix 10.11  - Notice Addresses....................................   79


















































                                      -iii-
<PAGE>
                             CONTRIBUTION AGREEMENT
                             ----------------------

     THIS Contribution Agreement (this "Agreement"),  is entered as of September
30,  1999,  by and  between  77  WEST  WACKER  LIMITED  PARTNERSHIP,  a  limited
partnership  organized under the laws of Illinois ("77 WWLP"),  and OTR, an Ohio
general partnership,  acting on behalf of and legally binding the State Teachers
Retirement  System of Ohio ("STRBO"),  an  instrumentality  of the State of Ohio
(such  partnership,  acting on behalf of STRBO,  "OTR"),  with  reference to the
following.
                                    RECITALS:

     A.  77 WWLP holds title to certain real  property  located in Chicago, Cook
County,  Illinois  commonly known as 77 West Wacker Drive, at which is located a
50 story  Class A office  building  with an area of  approximately  944,556  net
rentable  square  feet,  a health club  facility  with an area of  approximately
12,288 square feet located on an air rights parcel adjacent to such building,  a
restaurant  with an area of  approximately  4,800  square  feet  and 45  parking
spaces.

     B. 77 WWLP and OTR desire for 77 WWLP to form 77 West Wacker Drive, L.L.C.,
a limited liability company organized under the laws of Delaware (the "LLC").

     C.  Subsequent  to formation of the LLC, the parties wish for the following
to  occur:  (i) 77 WWLP to  transfer  to the LLC all of the  real  property  and
related  personal  property to which it holds title;  (ii) the LLC to borrow the
principal amount of $170,000,000 from an institutional  lender on the terms more
specifically  provided in Appendix 2.6 hereof; (iii) the LLC to pay the existing
indebtedness of 77 WWLP secured by 77 WWLP's property; (iv) following payment of
such  existing   indebtedness  and  at  the  same  time  as  or  following  such
contribution,   distribution  and  borrowing,  OTR  to  contribute  to  the  LLC
$66,000,000 as preferred  equity yielding a nine and one-half  percent (9?%) per
year cumulative return; (v) following payment of such existing  indebtedness and
at the same time as or following  such  borrowing,  OTR to contribute to the LLC
$22,000,000;  (vi) the LLC to pay in cash to 77 WWLP as a distribution an amount
equal to the amount  contributed  to the LLC by OTR,  (vii) 77 WWLP to assign or
distribute  its  membership  interest in the LLC to Prime Group  Realty  L.P., a
limited  partnership  organized under the laws of Delaware ("Prime") and, to the
extent required by Lender,  another affiliate of Prime; (viii) following payment
of  such  existing  indebtedness  and at the  same  time  as or  following  such
borrowing,  OTR and  Prime to  enter  into an  Amended  and  Restated  Operating
Agreement  governing  the LLC  substantially  in the form of  Exhibit D attached
hereto and  incorporated  herein;  and (ix)  following  payment of such existing
indebtedness   and  at  the  same  time  as  or  following  such   contribution,
distribution and borrowing, OTR to receive a membership interest in the LLC.

     NOW,  THEREFORE,  in  consideration  of the  foregoing  and the  respective
representations,   warranties,   covenants   and   agreements   of  each  party,
respectively, set forth herein, the parties hereto agree as follows:

                                    ARTICLE I

                                   DEFINITIONS

     Section 1.1 SPECIFIC  DEFINITIONS.  Terms with initial capital letters used
herein shall have the meanings ascribed to them below.

     "77 WWLP  Contribution"  shall mean the contribution of the Property to the
LLC as provided herein,  free,  clear and unencumbered  except for the Permitted
Exceptions.

     "77 WWLP Contribution Value" shall mean $110,000,000, as such amount may be
adjusted in accordance with Article VI.

                                      -1-
<PAGE>
     "Action(s)" shall mean any litigation or proceeding of any nature,  whether
at  law or in  equity,  before  any  court,  arbitrator,  arbitration  panel  or
Governmental Authority.

     "Affiliate"  shall mean,  with respect to any specified  Person,  any other
Person  that  directly,  or  indirectly  through  one  or  more  intermediaries,
controls,  is  controlled  by,  or is  under  common  control  with  the  Person
specified.  For the purpose of this  definition,  "control" means the ability to
direct or cause the direction of the management or affairs of a Person,  whether
through the direct or indirect  ownership  of voting  interests,  by contract or
otherwise.

     "Agreement" shall mean this Contribution Agreement,  including the exhibits
attached hereto.

     "Air Rights  Lease" shall mean a certain  lease dated March 7, 1991 between
American National Bank and Trust Company, as Trustee under trust agreement dated
November 26, 1985 and known as Trust Number 66121, as landlord,  and 77 WWLP, as
Tenant,  and recorded as Document  Number 91119739 in the office of the Recorder
of Cook County, Illinois.

     "Air Rights  Parcel" shall mean a certain  parcel of property  leased to 77
WWLP pursuant to the Air Rights Lease.

     "Appurtenances:  shall mean the interest of the tenant under the Air Rights
Lease on, in or appurtenant to the Air Rights Parcel and the rights of the party
named 77 West Wacker Limited  Partnership  pursuant to the Parking  Agreement in
the Transportation Building, including those affecting the property described in
Exhibit B-1 attached hereto and incorporated herein and any and all right, title
and  interest  of 77  WWLP  in and to all  intangible  property  that  is now or
hereafter  used  in  connection  with  the  operation,  ownership,  maintenance,
management   or  occupancy  of  the  Air  Rights   Parcel  or  the   Appurtenant
Improvements,  including without limitation, any and all of the following: plans
and  specifications  for the Air Rights Parcel or the Appurtenant  Improvements,
including as built plans,  unexpired  warranties,  guaranties,  indemnities  and
claims  against third  parties;  contract  rights  related to the  construction,
operation, repair, renovation, ownership or management of such Air Rights Parcel
or Appurtenant Improvements;  pending permit or approval applications as well as
existing permits,  approvals and licenses (to the extent assignable);  insurance
proceeds or condemnation awards to the extent provided in Sections 4.2 or 4.3 of
this Agreement;  marketing and promotional  brochures  related to the Air Rights
Parcel or the Appurtenant Improvements;  and books and records pertaining to the
Air Rights Parcel or the Appurtenant Improvements.

     "Appurtenant Improvements" shall mean the interests of the tenant under the
Air Rights Lease to all buildings,  improvements,  fixtures, structures, parking
areas and landscaping located on, in or appurtenant to the Air Rights Parcel, if
any, including the health club and the skywalks.

     "Bill of Sale and  Assignment"  shall mean an  agreement to be entered into
between  77  WWLP  and  the LLC  pursuant  to  which  the  LLC  assumes  certain
Liabilities  pertaining to the Property, and 77 WWLP transfers to the LLC all of
its right, title and interest in, to and under the Property.

     "Brokers" means BT Alex. Brown and Jones Lang LaSalle.

     "Capital Contribution" means, in the case of OTR, the OTR Contribution, and
in the case of 77 WWLP, the 77 WWLP Contribution.

     "Cleanup"  shall  mean all  actions  required  by  Environmental  Laws with
respect to the Property to: (a) clean up, remove,  treat or remediate  Hazardous
Materials  in the indoor or outdoor  environment;  (b)  prevent  the  Release of
Hazardous  Materials  so that  they do not  migrate,  endanger  or  threaten  to

                                      -2-
<PAGE>
endanger  public  health or welfare or the  indoor or outdoor  environment;  (c)
perform  studies and  investigations  and monitoring and care; or (d) respond to
any  government  requests  for  information  or documents in any way relating to
clean up,  removal,  treatment or  remediation or potential  clean up,  removal,
treatment  or  remediation  of Hazardous  Materials in the  workplace or outdoor
environment.

     "Closing" shall have the meaning set forth in Section 5.1.

     "Closing  Date" shall mean a date on or before  September 30, 1999, as such
date may be extended as provided in Section 3.4.

     "Closing  Documents" shall mean the documents that the parties are required
to deliver in Article V.

     "Code" shall mean the Internal Revenue Code of 1986, as amended.

     "Commission  Schedule"  means the  schedule  attached to this  Agreement as
Exhibit A and incorporated herein.

     "CCRs" shall have the meaning set forth in Section 3.8.

     "Debt" shall mean the obligation of the LLC to repay the Loan and the other
obligations of the LLC under the Loan Documents.

     "Deposit"  shall mean  $500,000  deposited  by OTR with the Escrow Agent as
provided in Section 2.2,  together  with any interest or other  earnings on such
$500,000.

     "Due  Diligence  Period"  shall  mean  the  period  from  the  date of this
Agreement through 11:59 p.m. (E.D.T.) on the Effective Date.

     "Effective  Date" shall mean the date on which each party to this Agreement
shall have executed and delivered it to each other.

     "Employment Laws" shall mean all federal,  state,  local and municipal Laws
in effect at or prior to the Effective  Date  relating to  employees,  dependent
contractors and independent  contractors and their  employment,  or rendition of
services,  including but not limited to those laws relating to taxation, health,
labor,  labor-management relations,  occupational health and safety, pay equity,
employment equity or discrimination, employment standards, benefits and workers'
compensation.

     "Endorsements" shall mean, (i) owner's comprehensive,  (ii) non-imputation,
and (iii)  those  endorsements  forming a part of the  proforma  policy of title
insurance attached as Appendix 2.7(2) hereto.

     "Environmental  Laws" shall mean all applicable  Laws relating to pollution
of  the  environment  or  protection  of  the  environment,  including,  without
limitation,  Laws  relating  to  Releases or  threatened  Releases of  Hazardous
Material  into the  environment  (including,  without  limitation,  ambient air,
surface  water,  groundwater,  land,  soil,  surface and  subsurface  strata) or
otherwise relating to the manufacture, processing, distribution, use, treatment,
storage, disposal, Release, transport or handling of Hazardous Material, and all
laws and regulations with regard to recordkeeping,  notification, disclosure and
reporting requirements respecting Hazardous Materials.

     "Environmental Permit" shall mean any permit, license, registration,  waste
identification  number,  variance  or other  authorization  of any  Governmental
Authority  relating to the  business or  operations  of 77 WWLP or the  Property
required by any Environmental Law.



                                      -3-
<PAGE>
     "ERISA" shall mean the Employee  Retirement Income Security Act of 1974, as
amended.

     "Escrow Agent" shall mean Chicago Title Insurance Company.

     "Escrow  Agreement"  shall mean the Escrow  Agreement to be entered into by
and among Prime,  77 WWLP, OTR and Chicago Title  Insurance  Company,  as Escrow
Agent, to be funded with the Deposit,  substantially in the form of Appendix 2.2
attached hereto and incorporated herein.

     "Existing  Debt" means the  indebtedness  of 77 WWLP to Existing Lender and
the obligations of 77 WWLP to Existing Lender under the Existing Mortgage.

     "Existing  Lender"  means  the  holder  of the  Existing  Mortgage  and the
indebtedness, the repayment of which the Existing Mortgage secures.

     "Existing   Mortgage"  means  a  certain  mortgage  and  related  documents
currently  encumbering  the  Property  securing the  indebtedness  of 77 WWLP to
Lehman Brothers Holdings, Inc.

     "Financial  Statements" shall have the meaning set forth in Section 3.2 and
Appendix 3.2.

     "Governmental   Authority"   shall  mean  any   federal,   state  or  local
governmental  department,  court,  commission,  board,  bureau,  agency,  taxing
authority or instrumentality having jurisdiction over the Property.

     "Hazardous  Materials"  shall mean all or any of the  following  substances
defined or listed  in, or  otherwise  classified  pursuant  to,  any  applicable
Environmental  Laws  as  "contaminants,"   "hazardous   substances,"  "hazardous
materials,"  "hazardous wastes,"  "pollutants,"  "toxic substances" or any other
formulation  intended to define,  list or classify substances by reason of their
adverse or  deleterious  properties  including but not limited to the following:
(a) oil,  petroleum or petroleum  derived  substances,  natural gas, natural gas
liquids or synthetic gas and drilling  fluids,  produced waters and other wastes
associated with the exploration, development or production of crude oil, natural
gas or geothermal  resources;  (b) any flammable  substances,  explosives or any
radioactive   materials;   (c)  underground  storage  tanks,  whether  empty  or
containing  any  substance;  (d)  asbestos  in any form that is or could  become
friable;  (e)  polychlorinated  biphenyls  or  any  electrical  equipment  which
contains any oil or dialectic fluid containing  polychlorinated  biphenyls;  and
(f) all  substances  defined  as  "hazardous  substances,  oils,  pollutants  or
contaminants" in the National Oil and Hazardous Substances Pollution Contingency
Plan, 40 C.F.R. ? 300.5, or defined as such by, or regulated as such under,  any
Environmental Law.

     "Improvements"   shall   mean  all   buildings,   improvements,   fixtures,
structures, parking areas and landscaping located on or in the Land.

     "Intangible  Property" shall mean all right,  title and interest of 77 WWLP
in and to all intangible personal property owned by 77 WWLP and now or hereafter
used in connection with the operation,  ownership,  maintenance,  management, or
occupancy of the Real Property,  including,  without limitation,  any and all of
the following:  trade names and trademarks  associated  with such Real Property,
including; the plans and specifications for the Improvements, including as-built
plans;  unexpired warranties,  guarantees,  indemnities and claims against third
parties;  contract  rights  related  to  the  construction,  operation,  repair,
renovation,  ownership or management of such Real  Property;  pending  permit or
approval  applications as well as existing  permits,  approvals and licenses (to
the extent assignable); insurance proceeds and condemnation awards to the extent
provided in Sections 4.2 or 4.3 of this  Agreement;  marketing  and  promotional
brochures and materials for the Property;  trade names and trademarks pertaining
to the Property; and books and records relating to the Property.


                                      -4-
<PAGE>
     "Knowledge"  with  respect to any  particular  representation  or  warranty
contained  in this  Agreement,  shall  mean the actual  knowledge  of Jeffrey A.
Patterson, James Runnion and/or Scott McKibben.

     "Land"  shall mean the land  described  in  Exhibit B  attached  hereto and
incorporated  herein and all and  singular  the  rights,  benefits,  privileges,
easements,  tenements,  hereditaments,  and appurtenances thereon or in any wise
appertaining  to the Land,  including  any and all mineral  rights,  development
rights, water rights and the like; and all right, title, and interest of 77 WWLP
in and to all strips and gores and any land lying in the bed of any street, road
or alley, open or proposed, adjoining the Land, if any.

     "Laws" shall mean statutes,  common laws, rules,  ordinances,  regulations,
codes, licensing requirements,  orders, writs, judgments,  injunctions, decrees,
licenses and permits of any Governmental Authority.

     "Lender" means  collectively the lenders making the Loan as contemplated in
Appendix 2.6 attached hereto,  including Westdeutsche  Immobilien Bank, a German
banking  association,  as a lender  and as  agent  for all of such  lenders,  as
contemplated in Appendix 2.6 attached hereto.

     "Leases"  shall mean,  as to the Property,  all leases,  subleases or other
agreements  pursuant  to which any Person  has the right to occupy  space in the
Improvements  (including  leases made after the date hereof as permitted by this
Agreement),  but  excluding  the Air Rights  Lease and any sublease or occupancy
agreement pertaining to the Air Rights Parcel.

     "Lease  Assignment"  shall mean the assignment of leases and rents pursuant
to which the LLC pledges the leases and rents of the Property in order to secure
its obligation to repay the Loan.

     "Liabilities"  shall mean  debts,  liabilities,  commitments,  obligations,
duties  and  responsibilities  of any kind and  description,  whether  absolute,
accrued,  contingent,  monetary or  nonmonetary,  direct or  indirect,  known or
unknown or matured or unmatured or of any other nature.

     "Lien" shall mean with respect to the Real  Property,  the  following:  any
mortgage,  pledge,  restriction,   security  interest,  claim,  charge,  adverse
interest in property,  lease, lien or other  encumbrance of any kind,  including
any property  interest or title of any vendor,  lessor,  lender or other secured
party under any conditional  sale contract or title retention  contract,  and in
the case of securities or equity interests,  any put, call or similar right of a
third party with respect to such securities or equity interests.

     "LLC" shall mean 77 West Wacker Drive, L.L.C., a Delaware limited liability
company.

     "Loan" shall mean the borrowing  contemplated by the LLC from the Lender in
the principal amount of $170,000,000.

     "Loan  Documents"  shall mean the  documents  evidencing  or  securing  the
indebtedness to repay the Loan.

     "Management  Agreement" shall mean a certain  Management  Agreement between
the LLC and  Prime to be  entered  into at  Closing,  in the form of  Exhibit  C
attached hereto and incorporated herein.

     "Manager"  shall  mean  Prime,   Prime  Group  Realty  Services,   Inc.,  a
corporation organized under the laws of Maryland, or an Affiliate of either.

     "Material damage" or "materially  damaged" shall have the meaning set forth
in Section 4.2.

                                      -5-
<PAGE>
     "Mortgage" shall mean the mortgage and security  agreement  encumbering the
Property to secure the obligation of the LLC to repay the Loan.

     "Notice Addresses" shall mean the addresses set forth in Appendix 10.11, as
the same may be changed in accordance with Section 10.11.

     "Objection Notice" shall have the meaning set forth in Section 3.4.

     "Operating  Agreement"  shall  mean  the  Amended  and  Restated  Operating
Agreement  of the LLC between  Prime and OTR, or between 77 WWLP and OTR, as the
case  may be,  substantially  in the  form  attached  hereto  as  Exhibit  D and
incorporated herein.

     "OTR Contribution" shall have the meaning provided in Section 2.3.

     "OTR Representative" shall have the meaning provided in Section 3.1.

     "Parking  Agreement"  means a certain  Parking  Agreement dated October 22,
1991 among 77 WWLP and American National Bank and Trust Company of Chicago,  not
personally but as trustee under trust agreement dated June 18, 1981 and known as
trust number 52947 and North Loop Transportation Center Limited Partnership.

     "Permitted Exceptions" shall mean:

          (a) Liens for taxes not yet due and payable;

          (b) tenants as tenants in possession only under the Leases without any
     option to purchase or right of first  refusal  with respect to the Property
     or any portion  thereof  (other than rights of first offer or first refusal
     to lease office space at the Property or similar rights);

          (c) exceptions approved by OTR as provided in Section 3.4;

          (d) exceptions  shown in the Pro Forma Title Policy attached hereto as
     Appendix 2.7(2); and

          (e) the Lien of the Loan Documents securing the Loan.

     "Person"  shall mean any natural  person,  corporation,  limited  liability
company,  general  partnership,   limited  partnership,  joint  venture,  union,
association, court, agency, government, tribunal,  instrumentality,  commission,
arbitrator, board, bureau or other entity or authority.

     "Personal  Property" shall mean all right, title and interest of 77 WWLP in
and to all tangible  personal  property  owned by 77 WWLP described in Exhibit E
attached hereto and incorporated herein and heretofore, now or hereafter used in
connection with the operation, ownership, maintenance,  management, or occupancy
of the Real Property,  but "Personal  Property" shall not mean personal property
owned by tenants of the Property  pursuant to Leases,  or personal property that
is (i) not  required  for the  use or  operation  of the  Real  Property  or the
Appurtenant  Improvements and (ii) is owned by Manager or owned by the operators
of the  health  club  located  in the Air  Space  Parcel or the  parking  garage
included in the Improvements.

     "Property"  shall  mean the Real  Property,  the  Leases,  the  Rents,  the
Personal Property, the Intangible Property and the Service Contracts.

     "Property  Information"  means the  documents,  materials  and  information
specified in Appendix 3.2 attached hereto and incorporated herein.

     "Property  Value"  means  $280,000,000,  as such  amount may be adjusted in
accordance with Article VI hereof.


                                      -6-
<PAGE>
     "Real Property" shall mean the Land and the Improvements.

     "Rents"  shall mean all income from the Real  Property,  including  without
limitation,  all fixed or base rent,  percentage rent,  additional rent or other
amounts  payable by tenants  under Leases with  respect to  operating  expenses,
taxes or other charges under the Leases but excluding  rent payable  pursuant to
the Air Rights  Lease,  amounts  payable  pursuant to the Parking  Agreement and
revenue of the health club operation located in the Air Rights Parcel.

     "Release"  shall mean any release,  spill,  emission,  discharge,  leaking,
pumping, injection, deposit, disposal, dispersal, leaching or migration into the
indoor or outdoor  environment  (including,  without  limitation,  ambient  air,
surface water, groundwater, land, soil and surface or subsurface strata) or into
or out of any property,  including the movement of Hazardous Material through or
in the  air,  soil,  surface  water,  groundwater  or  property,  if  applicable
Environmental  Laws  would  require  the  effect  of  any  of  the  same  on the
environment to be remedied or reported to a Governmental Authority.

     "Service" shall mean the Internal Revenue Service of the United States.

     "Service  Contracts" shall mean all service  contracts and other contracts,
agreements  or  instruments  relating  to  the  ownership,  use,  management  or
operation  of the  Property,  including  equipment  leases or any other lease in
which 77 WWLP is lessee, but excluding the Leases.

     "Subsidiary"  shall mean with respect to a Person any  corporation or other
entity the  majority of the voting  stock or other  equity  interest of which is
owned,  directly or indirectly,  beneficially or of record,  by such Person,  or
which is otherwise controlled, directly or indirectly, by such Person.

     "Supplemental   Property   Information"  means  any  additional   documents
furnished to OTR in accordance  with Section 3.2 hereof during the Due Diligence
Period.

     "Survey" shall mean the survey of the Real Property  prepared by a surveyor
licensed in the  jurisdiction  in which the Real Property is located,  a plat of
which 77 WWLP has  previously  delivered to OTR, to which plat such surveyor has
appended a  certificate  pursuant to which such  surveyor  certifies to OTR, the
Title Company and the LLC that the survey accurately  depicts the Property as of
a date subsequent to the Effective Date.

     "Tax Return" shall mean any return, report, document,  declaration or other
information or filing (including any related or supporting information) filed or
required to be filed with any taxing  authority or jurisdiction  with respect to
Taxes.

     "Title  Commitment"  shall mean a commitment  for an ALTA Form 1970 owner's
title  insurance  policy for the Real Property in the initial  amount of $10,000
(which shall be increased at Closing to $280,000,000) covering title to the Real
Property on or after the date of this Agreement, showing 77 WWLP as the owner of
the Fee Real Property and the rights of the tenant under the Air Rights Lease.

     "Title Company" shall mean Chicago Title Insurance Company.

     "Title  Policy"  shall mean an ALTA  Owner's  Policy  (1970  Form) of title
insurance  issued by the Title  Company as of the date and time of the recording
of the Deed,  in form and  substance  the same as the pro forma  policy of title
insurance attached hereto as Appendix 2.7(2).

     Section 1.2 TERMS  GENERALLY.  The  definitions  in Section 1.1 shall apply
equally to both the singular and plural forms of the terms defined. Whenever the
context may require,  any pronoun  shall  include the  corresponding  masculine,
feminine and neuter forms. The words "include," "includes" and "including" shall

                                      -7-
<PAGE>
be deemed to be followed by the phrase "without limitation" even if not followed
actually by such phrase unless the context expressly provides otherwise.  Unless
otherwise expressly defined, terms defined in this Agreement shall have the same
meanings when used in any Appendix, Exhibit or Schedule and terms defined in any
Appendix,  Exhibit or Schedule  shall have the same  meanings  when used in this
Agreement or in any other  Appendix,  Exhibit or Schedule.  The words  "herein,"
"hereof,"  "hereto" and  "hereunder"  and other words of similar import refer to
this Agreement as a whole and not to any particular provision of this Agreement.
The phrase "made  available" in this Agreement  shall mean that the  information
referred to has been made  available by the party in question.  The phrases "the
date of this Agreement",  "the date hereof", and terms of similar import, unless
the context otherwise requires,  shall be deemed to refer to the Effective Date.
References  to  "dollars"  or "$" in this  Agreement  shall mean  United  States
dollars.

                                   ARTICLE II

                            TERMS OF THE TRANSACTION

     Section 2.1  FORMATION  OF THE JOINT  VENTURE.  At least three (3) business
days prior to Closing, 77 WWLP shall prepare,  sign, and file with the Secretary
of State of Delaware the  Articles of  Organization  of the LLC. At Closing,  77
WWLP and OTR,  or Prime and OTR, as the case may be,  shall  execute and deliver
counterparts of the Operating Agreement,  provided that the conditions precedent
to the  performance  of such  obligations  are  satisfied  or waived as provided
herein.

     Section 2.2 DEPOSIT. Within five (5) business days after the end of the Due
Diligence  Period,  OTR  shall  deposit  the  Deposit  with  the  Escrow  Agent.
Contemporaneously  with the  execution of this  Agreement,  OTR, 77 WWLP and the
Escrow Agent shall  execute the Escrow  Agreement  substantially  in the form of
Appendix 2.2 attached hereto and incorporated  herein. The Deposit shall be held
and disbursed as provided in the Escrow Agreement.  At Closing,  the full amount
of the Deposit shall be (i)  disbursed to the LLC and (ii) credited  against the
OTR Contribution.

     Section 2.3 CASH CONTRIBUTION TO THE LLC.

          (a) At Closing,  OTR shall contribute to the LLC cash in the amount of
     $88,000,000  (the "OTR  Contribution"),  as such  amount may be adjusted in
     Article  VI  hereof,   provided  that  the  conditions   precedent  to  the
     performance of such obligation are satisfied or waived as provided  herein,
     upon the terms set forth herein.

          (b) In exchange for the OTR Contribution to the LLC, OTR shall receive
     at Closing a  membership  interest in the LLC as provided for and set forth
     in the Operating Agreement.

     Section 2.4 INSTRUMENTS OF TRANSFER AND CONVEYANCE.  In order to effect the
formation of the LLC and the OTR  Contribution  as  contemplated by Sections 2.1
and 2.3, on the Closing  Date,  77 WWLP and OTR shall  execute and  deliver,  or
cause to be executed and  delivered,  in escrow to the Escrow  Agent,  dated the
Closing Date,  subject only to Permitted  Exceptions,  the Closing Documents and
funds that  each,  respectively,  is  required  to deliver as more  particularly
provided in Article V.

         Section 2.5  77 WWLP CONTRIBUTION.

          (a) At or before the  Closing,  77 WWLP shall  transfer  to the LLC by
     delivery of the  Assignment and Deed as provided in Section 5.3 hereof good
     and  marketable  title  to the  Property  and  the  Appurtenances  and  the
     Appurtenant  Improvements,  free,  clear and  unencumbered  except  for the
     Permitted  Exceptions,  the Existing  Mortgage and otherwise upon the terms

                                      -8-
<PAGE>
     set forth  herein.  At or before the  Closing,  77 WWLP shall  satisfy  the
     Existing Debt as provided in Section 2.8 hereof.

          (b) In exchange for the 77 WWLP  Contribution,  77 WWLP shall have the
     right to receive at Closing a  membership  interest  in the LLC as provided
     for and set  forth in the  Operating  Agreement.  Contemporaneous  with the
     distributions  specified in Section 2.9, 77 WWLP shall assign to Prime, and
     if required by Lender, an Affiliate of Prime, its right, title and interest
     in 77 WWLP's right to  membership in the LLC, and 77 WWLP shall cause Prime
     to assume all and singular,  the obligations of 77 WWLP under the Operating
     Agreement,  whether such  performance  was due prior or  subsequent to such
     assignment.

     Section 2.6 DEBT  FINANCING OF  PROPERTY.  77 WWLP and OTR intend that they
will  authorize,  empower  and direct the LLC (i)(a) to borrow  $170,000,000  to
finance in part the LLC from Lender and (b) agree to repay the Loan on the terms
set forth in Appendix 2.6  attached  hereto and  incorporated  herein or (ii) to
accept title to the Property  subject to the lien of the Loan  Documents  and to
assume the  obligations  of 77 WWLP under the Loan  Documents  accruing from and
after Closing.

     77 WWLP and OTR shall  cooperate  with each other during the Due  Diligence
Period to obtain the Loan on the terms set forth in Appendix  2.6 and  otherwise
reasonably  satisfactory to each of OTR and Prime. 77 WWLP shall notify OTR from
time to time of its progress in obtaining such Loan  commitment and  negotiating
the terms of the Loan  Documents  and shall  respond  to  requests  from OTR for
information on such progress.

     If the  proposed  commitment  of  Lender  to make the  proposed  Loan,  the
proposed Loan and the Loan  Documents  contain and effect  economic terms of the
Loan set forth in  Appendix  2.6 and if the terms of the Loan  Documents  do not
contain  noneconomic terms materially  adverse to either 77 WWLP or OTR, 77 WWLP
and OTR shall  authorize,  direct and  empower  the LLC either (i) to obtain the
Loan and to execute and deliver the Loan Documents in favor of Lender at Closing
or  (ii) to  accept  title  to the  Property  subject  to the  lien of the  Loan
Documents  and to assume the  obligations  of 77 WWLP  under the Loan  Documents
accruing  from and after  Closing.  At least five (5) days prior to the  Closing
Date, 77 WWLP shall furnish to OTR copies of all of the proposed Loan  Documents
and notify OTR whether the proposed Loan Documents  provide for a Loan effecting
the economic terms set forth in Appendix 2.6 and do not provide for  noneconomic
terms materially adverse to 77 WWLP.

     If OTR determines that the proposed Loan Documents (i) do not provide for a
Loan  effecting  the  economic  terms set forth in Appendix  2.6 or (ii) provide
noneconomic  terms materially  adverse to OTR, OTR shall elect in writing to (i)
terminate this Agreement or (ii) raise  objections by providing  notice thereof.
If OTR does not give such notice  within five days after receipt from 77 WWLP of
the  proposed  Loan  Documents  OTR  shall be  deemed  to have  terminated  this
Agreement.  If OTR  notifies  77  WWLP of any  such  objections,  77 WWLP  shall
exercise  reasonable  efforts for two (2) business days following such notice to
cause such objections to be removed or corrected. If necessary, the Closing Date
shall be extended to permit 77 WWLP to use such two (2) business day period.  If
despite such reasonable  efforts,  77 WWLP is unable to cause such objections to
be removed or corrected  to OTR's  reasonable  satisfaction  within such two (2)
business  day period,  then OTR may elect on or prior to the date that is twenty
(20) days  following  the date that it gave  notice  of such  objections  to (i)
terminate  this Agreement or (ii) accept the proposed Loan Documents as to which
it had previously  objected  without the removal or correction of the objections
that 77 WWLP has been unable to remove or correct. If OTR so elects to terminate
or accept,  such election  shall be OTR's sole and  exclusive  remedy under this
Agreement, at law or in equity with respect to such objection.



                                      -9-
<PAGE>
     If 77 WWLP is unable,  prior to the Closing Date, to negotiate  with Lender
the terms of Loan  Documents  that (i) provide for a Loan effecting the economic
terms set forth in Appendix 2.6 from Lender and (ii) do not provide  noneconomic
terms materially  adverse to 77 WWLP,  despite  reasonable  efforts to do so, 77
WWLP may elect to terminate this Agreement by written notice to OTR, given on or
before the Closing Date.

     The  obligations of the LLC to repay the Loan and the other  obligations of
the LLC under the Loan Documents are sometimes  referred to herein  collectively
as the "Debt".

     Section 2.7 TITLE  POLICY.  (a) 77 WWLP shall do those things  specified in
the  following  Section  2.7(b) in order to induce the Title Company to issue to
the LLC at the Closing,  or irrevocably  commit in writing at Closing to deliver
within  fifteen  (15) days  following  Closing,  the Title  Policy  meeting  the
following requirements:

          (i) the effective  time of the Title Policy shall be the date and time
     of recording of the Deed;

          (ii) the amount of the Title Policy shall be $280,000,000;

          (iii) the insured under the Title Policy shall be the LLC;

          (iv)  the  Title  Policy  shall  be  reinsured   with  direct   access
     reinsurance  agreements  satisfactory  to OTR,  77 WWLP  and  Prime  by the
     reinsurers  identified in Appendix  2.7(1) with the limits of liability set
     forth in Appendix 2.7(1); and

          (v) the Title Policy shall be in the same form as the proforma  policy
     of title  insurance  attached hereto as Appendix 2.7(2) attached hereto and
     incorporated herein.

     (b)  77 WWLP shall:

          (i) request Title Company to issue the Title Policy;

          (ii) cause the  satisfaction of the conditions  precedent set forth in
     the Title Commitment and the Endorsements included in it to Title Company's
     liability to issue the Title Policy  pursuant to the Title  Commitment that
     are more  particularly  described in Appendix  2.7(3)  attached  hereto and
     incorporated herein; and

          (iii) perform 77 WWLP's obligations hereunder.

     Section  2.8  EXTINGUISHMENT  OF  EXISTING  DEBT.  At or prior to  Closing,
provided  that the  conditions  precedent  provided  in Section 5.2 hereof to 77
WWLP's duty to perform its  obligations  under  Sections  5.1 and 5.3 hereof are
satisfied or waived by 77 WWLP,  including the  disbursement  of the proceeds of
the  Loan to the LLC  and the  LLC's  making  such  proceeds  available  for the
satisfaction  of the Existing  Debt,  77 WWLP shall satisfy in full the Existing
Debt,  pursuant to a payoff  letter  obtained by it with respect to the Existing
Debt  satisfactory  to the Title Company and,  within thirty (30) days following
Closing,  shall obtain a full and  complete  release in  reasonable  form of the
Property the Appurtenances and the Appurtenant Improvements from the Lien of the
Existing Mortgage.  For such purpose,  77 WWLP may use the proceeds of the Loan.
If the payoff  letter is  incorrect,  and the Existing  Debt is not satisfied in
full, 77 WWLP shall immediately satisfy the Existing Debt in full at its expense
upon  receiving  written  notice that it has not  satisfied the Existing Debt in
full. If excess funds are paid to the holder of the Existing Debt, 77 WWLP shall
be entitled to pursue, collect and keep recovery of any such excess payment.



                                      -10-
<PAGE>
         Section 2.9  DISTRIBUTION  TO 77 WWLP.  At Closing,  provided  that the
Existing  Debt has  been  paid in full in  accordance  with  the  payoff  letter
obtained  from the holder of the Existing Debt  contemplated  in Section 2.9 and
the Title Policy is issued,  77 WWLP and OTR shall authorize and empower the LLC
to distribute the proceeds of the OTR  Contribution to 77 WWLP or as directed by
77 WWLP except for an amount of the OTR  Contribution  equal to the fees payable
as financing fees in connection  with the obtaining of the Loan (the  "Financing
Fees").  At  Closing,  77 WWLP and OTR shall  authorize  and  empower the LLC to
distribute  an  amount  of the  OTR  Contribution  equal  to the  amount  of the
Financing Fees to the person or persons entitled to the payment of the Financing
Fees.

                                   ARTICLE III

                                   INSPECTION

     Section  3.1 DUE  DILIGENCE;  INDEMNITY.  OTR shall have the Due  Diligence
Period  in  which  to  examine,  inspect,  and  investigate  the  Property,  the
Appurtenances and the Appurtenant Improvements and the proposed transaction and,
in OTR's sole and absolute  judgment and  discretion,  to determine  whether the
Property and the proposed transaction is satisfactory to OTR.

     Upon  reasonable  advance  notice to 77 WWLP and  subject  to the rights of
tenants  under  Leases,  OTR  and its  agents,  employees  and  representatives,
contractors,   architects   and  other   parties   designated   by  OTR  ("OTR's
Representative")  shall,  during  the term of this  Agreement,  have  reasonable
access during normal business hours to the Property,  the  Appurtenances and the
Appurtenant  Improvements and all books and records for the Property that are in
the  possession  or control of 77 WWLP or its agents or managers for the purpose
of conducting analyses, surveys,  architectural,  engineering,  geotechnical and
environmental  inspections and tests (including  reasonable intrusive inspection
and  sampling  after  prior  written  notice to 77 WWLP and in the  presence  of
Manager),  and any other inspections,  studies,  or tests reasonably required by
OTR after prior  written  notice to 77 WWLP and in the presence of Manager.  OTR
shall  have  the  right  to  conduct  a  "walk-through"  of  the  Property,  the
Appurtenances  and the  Appurtenant  before  Closing,  subject  to the rights of
tenants  under  Leases  and  accompanied  by  Manager.  In  the  course  of  its
investigations,  OTR may make inquiries,  in the manner  described below, to the
Manager, Lender, and, in the manner described below, the following tenants: R.R.
Donnelley & Son Company,  Jones Day Reavis & Pogue LLP,  and Everen  Securities,
Inc.

     OTR  shall  keep  the  Property,  the  Appurtenances  and  the  Appurtenant
Improvements  free  and  clear  of any  liens  arising  out of  such  entry  and
inspection and will indemnify, defend, and hold 77 WWLP, its partners, officers,
directors,  agents and  employees,  harmless  from all such liens and any claims
asserted by third parties against 77 WWLP, or its partners, officers, directors,
agents or employees  (other than those arising out of the  negligence or willful
misconduct  of 77 WWLP) to recover for personal  injury or property  damage as a
result of OTR's  Representatives' entry onto the Property, the Appurtenances and
the  Appurtenant  Improvements.  If any inspection or test damages the Property,
OTR at its sole  cost will  restore  the  Property,  the  Appurtenances  and the
Appurtenant  Improvements to the condition they were in immediately prior to any
such inspection or test in a manner  reasonably  satisfactory to 77 WWLP.  OTR's
obligations  under  this  Section  3.1 shall  survive  the  termination  of this
Agreement and, if applicable, the Closing.

     During the fourteen (14) day period  following the Effective  Date, 77 WWLP
shall schedule and reschedule,  if necessary,  meetings among representatives of
77 WWLP and OTR and representatives of the following tenants under Leases having
responsibility on behalf of such tenants for such Leases:  (i) R.R.  Donnelley &
Son Company,  (ii) Jones Day Reavis & Pogue LLP,  and (iii)  Everen  Securities,
Inc.  The  purpose  of  such  meetings  is to  give  representatives  of OTR the

                                      -11-
<PAGE>
opportunity to interview such tenants  concerning  their Leases and the Property
as part of OTR's due diligence.

     If (i) such meetings do not occur within  fourteen (14) days  following the
Effective Date or (ii) if OTR is not satisfied in its sole  discretion with such
meetings,  OTR may on or before the  expiration of such fourteen (14) day period
either (a) terminate this Agreement by notice to 77 WWLP or (b) raise objections
by providing notice thereof.  If OTR does not give 77 WWLP notice that it has no
objections  within such  fourteen  (14) day period,  OTR shall be deemed to have
terminated the  Agreement.  If OTR notifies 77 WWLP of any such  objections,  77
WWLP shall have the option,  but not the obligation,  within ten (10) days after
delivery of such notice to remove or cause to be corrected OTR's objections.  If
77 WWLP fails or refuses to cause such  objections to be removed or corrected to
OTR's satisfaction during within such ten (10) day period, then OTR may elect on
or prior to the date that is twenty  (20) days  following  the date that it gave
notice of such  objections  to (i) terminate  this  Agreement or (ii) accept the
Property  regardless of such objections and proceed to Closing without deduction
from the OTR Contribution or reduction of the 77 WWLP Contribution Value. If OTR
so elects to terminate or accept this  Agreement,  such election  shall be OTR's
sole and exclusive remedy under this Agreement, at law or in equity with respect
to such  objection.  If OTR makes no such  election  during such twenty (20) day
period, OTR shall be deemed to have elected to terminate this Agreement.

     Section 3.2 DELIVERY OF PROPERTY INFORMATION BY 77 WWLP AND PRIMe. In order
to assist OTR with its inspection and review of the Property,  the Appurtenances
and the Appurtenant  Improvements,  77 WWLP shall, within five (5) business days
after  the  date  of this  Agreement,  provide,  to the  extent  not  previously
provided,  to OTR true,  correct and  complete  copies of the items set forth on
Appendix 3.2 to this Agreement with respect to the Property,  the  Appurtenances
and the Appurtenant  Improvements  (collectively,  the "Property  Information"),
except  that  copies  of the  items  marked  (1) need not be  delivered  to OTR.
Instead,  OTR, at its option may inspect and copy such items upon request during
the Due Diligence Period or otherwise prior to Closing.  If any such item is not
in  possession  or control of 77 WWLP or its agents or managers,  or  reasonably
capable of being  generated by 77 WWLP or its agents or managers,  77 WWLP shall
provide to OTR a written  certification to that effect.  During the term of this
Agreement,  77 WWLP shall provide OTR with any document  described  above as and
when it  comes  into the  possession  or  control  of 77 WWLP or its  agents  or
managers,  or is produced by 77 WWLP or its agents or managers after the initial
delivery of the Property  Information.  Without limiting the foregoing,  77 WWLP
shall make all other documents, files and information concerning the Property in
the  possession  or control of 77 WWLP or its agents or managers,  available for
OTR's  inspection  and copying at the office of Prime or such other  location as
shall be mutually agreed by the parties. OTR acknowledges receipt of such of the
Property Information as is set forth in Appendix 3.2 to this Agreement.

     Section 3.3 TITLE AND SURVEY.  Within ten (10) days after OTR  acknowledges
receipt of such of the Property  Information as is set forth in Appendix  3.2(b)
to this Agreement,  77 WWLP shall, at its cost and expense, order to be prepared
and delivered to OTR with respect to the  Property,  the  Appurtenances  and the
Appurtenant  Improvements:  (i) the Title  Commitment,  (ii) to the  extent  not
previously  delivered to OTR true,  complete and legible copies of all documents
referenced  in the Title  Commitment,  (iii) the  Survey  and (iv) UCC  searches
performed by a search company  reasonably  acceptable to OTR, with respect to 77
WWLP,  from the  Secretary of State of Illinois and from the County  Recorder in
which the Property is located and, if other than Illinois, from the Secretary of
State in the state in which the chief  executive  office of Prime and 77 WWLP is
located.  OTR  acknowledges  receiving  the Title  Commitment  and copies of the
documents referenced in it.





                                      -12-
<PAGE>
     Section  3.4  OBJECTION  NOTICE.  If  OTR  is not  satisfied  in  its  sole
discretion  with  any of its  inspections,  reviews  or with  any  other  matter
concerning any or all of the Property,  the  Appurtenances  and the  Appurtenant
Improvements or the proposed transaction, OTR may, on or prior to the expiration
of the Due Diligence Period, either (i) terminate this Agreement by notice to 77
WWLP, or (ii) raise certain objections with respect to the Property by providing
notice in writing thereof (the "Objection  Notice").  The Objection Notice shall
specify which matters (the "Objections") OTR does not find satisfactory.  If OTR
does  not  provide  an  Objection  Notice  or a  notice  stating  that it has no
Objections prior to the end of the Due Diligence Period,  OTR shall be deemed to
have terminated this Agreement.

     If OTR timely provides an Objection  Notice, 77 WWLP shall have the option,
but not the  obligation  within ten (10) days after  delivery of such  Objection
Notice to remove or cause to be  corrected  to OTR's  satisfaction,  all of such
Objections.  In all cases, provided that the conditions to the obligations of 77
WWLP set forth in Section 5.2 are met, 77 WWLP shall be  obligated at Closing to
fully discharge (i) all Liens (other than the Lien of nondelinquent  taxes) of a
definite and ascertainable amount and (ii) liens of a definite and ascertainable
amount  (other  than  the  lien  of   nondelinquent   taxes  and  any  Permitted
Appurtenance   Liens  (as  defined  in  this  Section  3.4))   encumbering   the
Appurtenances  or the Appurtenant  Improvements to the extent that any of (i) or
(ii) (exclusive of (a) the Existing Mortgage and (b) any Permitted  Appurtenance
Liens)  represent a charge or charges of $250,000 or less in the  aggregate  and
result from the intentional acts of 77 WWLP, that are not  specifically  assumed
by the LLC or accepted by OTR in writing and (ii) the Existing Mortgage.

     For the purpose of this Agreement,  Permitted Appurtenance Liens shall mean
the following:  (i) liens that are subordinate to the rights of the tenant under
the Air Space Lease; (ii) liens that are subordinate to the rights of the entity
named 77 West Wacker Limited Partnership under the Parking Agreement;  (iii) the
lien of a certain  mortgage  dated May 1, 1987 and recorded in the office of the
Recorder of Cook County,  Illinois on May 12, 1987 as Document Number  87254852;
and (iv) the lien of taxes currently delinquent encumbering the area beneath the
Air Rights Parcel, provided that such lien is a Permitted Appurtenance Lien only
if at Closing 77 WWLP executes and delivers to OTR the letter agreement,  a copy
of which is  attached  hereto  as  Appendix  3.6 and  incorporated  herein  (the
"Delinquent  Tax Letter  Agreement").  For the  purpose of this  Agreement,  the
Disapproved  Encumbrances are (i) the Existing Mortgage and (ii) Liens and liens
specified in the  immediately  preceding  grammatical  paragraph that 77 WWLP is
obliged to discharge fully at Closing.  77 WWLP shall not have any obligation to
remove  or  cause  to  be  corrected  any  Objection   except  for   Disapproved
Encumbrances.

     If 77 WWLP  fails or  refuses to cause the  Objections  to be  removed  and
corrected to OTR's  satisfaction  within such ten (10) day period,  then OTR may
elect,  on or prior to the date and time  that is  twenty  (20)  days  after the
delivery of the Objection  Notice,  at 5:00 p.m.,  E.D.T., to (i) terminate this
Agreement, or (ii) accept the Property subject to any Objections (other than the
Disapproved  Encumbrances,  which 77 WWLP must discharge as provided  earlier in
this Section  3.4) and proceed to Closing.  If OTR elects to terminate or accept
this  Agreement with respect to an Objection that is not so removed or corrected
and that is not a Disapproved Encumbrance, such election shall be OTR's sole and
exclusive  remedy  under this  Agreement,  at law or equity with respect to such
Objection.  If OTR makes no such election  during such twenty (20) day period to
terminate or so to accept the Property  subject to any Objections,  OTR shall be
deemed to have elected to terminate this Agreement.

     If after the  expiration  of the Due  Diligence  Period,  the Title Company
revises the Title Commitment or the surveyor revises the Survey to add or modify
exceptions,  or to add  or  modify  conditions  to  the  issuance  of any of the
Endorsements,  then,  unless  OTR  elects  by  notice  to Prime to  accept  such


                                      -13-
<PAGE>
exceptions or conditions within five (5) days after being notified thereof, then
this Agreement shall be deemed terminated.  If, within such five (5) day period,
OTR notifies 77 WWLP that it objects to such new matters  (the  "Post-Commitment
Objection  Notice")  then 77 WWLP will have the option,  but not the  obligation
within ten (10) days after delivery of such Post-Commitment  Objection Notice to
remove or cause to be corrected, or to commit to remove or cause to be corrected
prior to Closing,  to OTR's  satisfaction,  all of such new matters  (except for
Disapproved  Encumbrances,  which 77 WWLP must discharge as provided  earlier in
this Section 3.4). If 77 WWLP fails or refuses to cause such new matters  (other
than Disapproved Encumbrances,  which 77 WWLP must discharge as provided earlier
in this Section 3.4) to be removed or  corrected  to OTR's  satisfaction,  or to
become legally  obliged to remove or cause to be corrected such matters to OTR's
satisfaction  (other than Disapproved  Encumbrances) prior to Closing, in either
event  within  such ten (10) day  period,  then OTR may  elect,  as its sole and
exclusive remedy under this Agreement,  at law or in equity,  on or prior to the
date and time that is ten (10) days after the  delivery  of the  Post-Commitment
Objection Notice, at 5:00 p.m.,  E.D.T., to (i) terminate this Agreement or (ii)
accept the Property  subject to such new matters and proceed to Closing.  If OTR
so elects to terminate or accept this  Agreement,  such election  shall be OTR's
sole and exclusive remedy under the Agreement,  at law or in equity with respect
to such matter arising after the expiration of the Due Diligence  Period (except
for Disapproved  Encumbrances,  which 77 WWLP must discharge as provided earlier
in this Section  3.4).  If OTR makes no such  election  within such ten (10) day
period to terminate  or so to accept the  Property  subject to such new matters,
OTR shall be deemed to have elected to terminate this Agreement.

     If  necessary,  the  Closing  Date  shall be  extended  the  number of days
necessary  to give  effect  to the  notice  and cure  periods  set forth in this
Section 3.4.

     If OTR terminates this Agreement as provided in this Section 3.4 or if this
Agreement is deemed  terminated  pursuant to this Section 3.4, the Deposit shall
be immediately  returned to OTR, and no party shall have any further obligations
hereunder, except as specifically set forth in this Agreement.

     Section 3.5 Intentionally deleted.

     Section 3.6 Intentionally deleted.

     Section  3.7 TENANT  ESTOPPELS.  OTR shall not be  obliged  to perform  its
obligations at Closing unless the following condition is satisfied: at least two
(2) business  days prior to the Closing,  the LLC and OTR receive duly  executed
estoppel certificates from (i) Jones Day Reavis & Pogue, (ii) Everen Securities,
Inc., (iii) R.R.  Donnelley & Sons Company,  and (iv) other tenants under Leases
that  collectively  comprise not less than (a) ninety-five  percent (95%) of the
rentable  square  feet  of the  Property  or,  (b)  if  duly  executed  estoppel
certificates  are received from each tenant  occupying at least one entire floor
of the  Improvements,  eighty-five  percent (85%) of the rentable square feet of
the  Property.  Such  estoppels  shall be in the forms set forth in Appendix 3.7
attached hereto and  incorporated  herein (the "Tenant  Estoppels").  The Tenant
Estoppels  must be (i) dated no  earlier  than  thirty  (30)  days  prior to the
Closing,  (ii)  consistent  in all  material  respects  with the  Leases and the
statements of the tenants in the tenant interviews  conducted as contemplated in
Section 3.1 and (iii) be consistent with the following statements: (a) the Lease
is in full force and effect; (b) except as disclosed in Appendix 7.1(a), neither
77 WWLP nor the tenant is in default under the Lease; (c) except as disclosed in
Appendix 7.1(c), the tenant has not asserted, and the tenant has no, defenses or
offsets to rent  accruing  after the  Closing  Date;  (d) except as set forth in
Appendices 6.10(a), 6.10(b), or 7.1(c) hereto, all of the landlord's obligations
to construct tenant improvements or reimburse the tenant for tenant improvements
under the Lease have been paid or performed in full; and (e) except as set forth
in the Lease, all concessions (other than any unexpired rent abatement set forth
in the Lease) from the landlord have been paid and performed in full.

                                      -14-
<PAGE>
     Prime  and 77 WWLP  shall  have  provided  OTR with  copies  of the  Tenant
Estoppels for OTR's review and comment before delivering the Tenant Estoppels to
tenants.  Prime and 77 WWLP shall use the following efforts to obtain the Tenant
Estoppels  from all tenants under Leases in a timely  manner:  (i) 77 WWLP shall
mail proposed Tenant Estoppels to each tenant of the Property;  and (ii) 77 WWLP
shall follow up  telephonically  once every three business days prior to Closing
to encourage such tenants to execute and deliver such Tenant  Estoppels.  If the
required  Tenant  Estoppels  are not timely  delivered  to OTR, or if any Tenant
Estoppel either does not meet the foregoing  requirements or discloses any facts
inconsistent  with  the  Leases  and  objectionable  to OTR  in  its  reasonable
discretion,  OTR may elect on or before the  earlier of (i) one (1) day prior to
the Closing Date or (ii) ten (10) days following  receipt of the relevant Tenant
Estoppel,  to either:  (i) terminate this Agreement by delivering written notice
to Prime one (1) day prior to  Closing,  in which  event  the  Deposit  shall be
promptly returned to OTR, and neither party shall have any further  obligations,
except as specifically set forth herein;  or (ii) waive the satisfaction of this
condition and proceed with Closing.  If OTR fails to make such election at least
one day prior to the  Closing  Date,  OTR shall be  deemed  to have  elected  to
terminate this Agreement.

     Section  3.8 AIR  RIGHTS  LEASE.  OTR shall not be  liable to  perform  its
obligations  at Closing  unless the following  condition is satisfied:  prior to
Closing, 77 WWLP shall deliver to OTR an estoppel  certificate  addressed to OTR
and the LLC, in the form attached as Appendix 3.8 and incorporated herein, or if
not in such form, in such form as is otherwise  reasonably  satisfactory to OTR,
from the landlord under the Air Rights Lease.


                                   ARTICLE IV

                           OPERATIONS AND RISK OF LOSS

     Section 4.1 ONGOING OPERATIONS. From the Effective Date through the Closing
Date:

               (a) OPERATION OF PROPERTY. 77 WWLP shall maintain the Property in
          substantially  its  current  condition  and  in  compliance  with  all
          applicable   laws  and   regulations.   77  WWLP  shall  maintain  the
          Appurtenances  and the Appurtenant  Improvements in substantially  the
          current  condition of each,  and in the condition  required by the Air
          Rights  Lease.  Except  as  necessary  to  comply  with the  preceding
          sentence,  77 WWLP  shall  not make any  material  alterations  to the
          Property,  the  Appurtenances  or the Appurtenant  Improvements or any
          portion  thereof  without OTR's prior written  consent.  77 WWLP shall
          perform its obligations under all Leases,  Service Contracts and other
          agreements  that may affect the  Property,  the  Appurtenances  or the
          Appurtenant Improvements.

               (b) NEW CONTRACTS. 77 WWLP shall not amend,  terminate,  exercise
          any rights or options under,  grant  concessions  regarding,  or enter
          into any contract or agreement  that will be an  obligation  affecting
          the Property,  the  Appurtenances  or the Appurtenant  Improvements or
          binding  on the LLC after  Closing  (other  than a Lease,  as to which
          Section 4.1(g) applies), except contracts entered into in the ordinary
          course of business  that are  terminable  without  cause or penalty on
          30-days' notice, without OTR's prior consent.

               (c)  LISTINGS  AND  OTHER  OFFERS.  77 WWLP  shall  not  list the
          Property,  the Appurtenances or the Appurtenant  Improvements with any
          broker other than the Brokers or  otherwise  make or accept any offers
          to sell  all or any part of the  Property,  the  Appurtenances  or the
          Appurtenant  Improvements,  engage in any  discussions or negotiations


                                      -15-
<PAGE>
          with any third party with respect to the sale or other  disposition of
          the Property,  the  Appurtenances  or the Appurtenant  Improvements or
          enter  into any  contracts  or  agreements  (whether  binding  or not)
          regarding  any  disposition  of all or any part of the  Property,  the
          Appurtenances or the Appurtenant Improvements.

               (d) REMOVAL AND  REPLACEMENT OF TANGIBLE  PERSONAL  PROPERTY.  77
          WWLP shall not remove any Personal  Property except as may be required
          for necessary  repair or replacement or on account of  obsolescence of
          such Personal  Property.  Any such repair and replacement  shall be of
          equal quality and quantity as existed as of the time of its removal.

               (e)  MAINTENANCE OF INSURANCE.  77 WWLP shall carry its insurance
          in effect  as set forth in the  Property  Information,  or  equivalent
          substitute insurance, through the Closing Date.

               (f)  MAINTENANCE OF PERMITS.  77 WWLP shall maintain (or cause to
          be  maintained)  in  existence  all  licenses,  permits and  approvals
          necessary or reasonably  appropriate  to the  ownership,  operation or
          improvement  of the Property,  the  Appurtenances  or the  Appurtenant
          Improvements.

               (g)  LEASING.   77  WWLP  shall  not  amend,   terminate,   grant
          concessions  regarding,  or enter into any Lease of space in excess of
          10,000  square feet of net rentable  area without  OTR's prior written
          consent. OTR shall not unreasonably  withhold or delay its consent. If
          OTR fails to object or  otherwise  reply to a request  for  consent by
          Prime or 77 WWLP within five (5)  business  days after  receipt of (i)
          any  such  request  by  Prime  or 77 WWLP  and  (ii)  all  information
          requested  by OTR  that is  reasonably  required  in  order to make an
          informed  decision,  OTR  shall be deemed  to have  consented  to such
          proposed  action.  OTR acknowledges and agrees that the economic terms
          of the Leases  provided in the memorandum from Scott McKibben to Steve
          Huber attached to Appendix 6.1(e) are satisfactory to OTR and that OTR
          consents to the entering of Leases to the  proposed  tenants set forth
          in such memorandum provided such Leases contain the economic terms set
          forth  in such  memorandum  and are  substantially  in the form of the
          standard form of Lease contained in the Property Information.

     Section 4.2 DAMAGE.  77 WWLP shall bear risk of loss to the  Property,  the
Appurtenances  and the Appurtenant  Improvements  from the Effective Date to and
including the Closing Date.  77 WWLP shall  promptly give OTR written  notice of
any damage to the Property,  the  Appurtenances or the Appurtenant  Improvements
describing such damage, stating whether such damage and loss of rents is covered
by insurance and the estimated  cost of repairing  such damage.  In the event of
any material  damage  (described  below) to or  destruction  of the Property the
Appurtenances or the Appurtenant  Improvements or any portion thereof,  OTR may,
at its option, by notice to 77 WWLP given within ten (10) business days after 77
WWLP  provides the above  described  notice to OTR (and if necessary the Closing
Date shall be extended to give OTR the full ten (10) business day period to make
such election):  (i) terminate this Agreement,  in which event the Deposit shall
be immediately  returned to OTR, or (ii) proceed under this Agreement,  in which
event 77 WWLP  shall  cause  any  insurance  proceeds  (including  any rent loss
insurance  applicable  to any  period on and after  the  Closing  Date) due as a
result of such damage or  destruction  to be paid to the LLC,  and the LLC shall
assume responsibility for such repair. If OTR fails to timely make such election
to terminate or proceed,  OTR shall be deemed to have elected to terminate  this
Agreement  with  respect to the Property as provided  above.  If OTR elects (ii)
above,  OTR may extend the Closing Date for up to an additional 30 day period in
which to obtain insurance settlement agreements with the insurers of 77 WWLP. 77
WWLP will  cooperate  with OTR in  obtaining  the  insurance  proceeds  and such
agreements from the insurers of 77 WWLP. If the Property,  the  Appurtenances or


                                      -16-
<PAGE>
the Appurtenant Improvements are not materially damaged, then OTR shall not have
the right to terminate this Agreement, but 77 WWLP shall commence and diligently
pursue the repair of the damage before the Closing using the insurance  proceeds
in a  manner  reasonably  satisfactory  to  OTR,  or,  if  such  repairs  cannot
reasonably  be  completed  before  the  Closing,  at  Closing  77 WWLP shall (i)
contribute to the LLC any and all insurance  proceeds  received by it on account
of such  damage  that 77 WWLP has not  expended  to make such  repairs  and (ii)
assign  to the LLC all of 77  WWLP's  rights  in,  to and  under  any  insurance
policies  covering such damage and proceeds  thereof  payable on account of such
damage, in which event, the LLC shall thereafter complete such repair. "Material
damage" and  "materially  damaged"  means  damage  that (x) in OTR's  reasonable
estimation  exceeds  $5,000,000 to repair,  (y) entitles any tenant occupying in
excess of 10,000 net  rentable  square feet to  terminate  its Lease,  or (z) in
OTR's reasonable estimation, will take longer than 120 days to repair.

         Section 4.3  CONDEMNATION.  If from and after the Effective Date to and
including the Closing Date, 77 WWLP obtains  Knowledge  that any  proceedings in
eminent domain are contemplated, threatened or instituted by any body having the
power of eminent domain with respect to the Property,  the  Appurtenances or the
Appurtenant  Improvements  or any portion  thereof,  77 WWLP shall notify OTR in
writing.  OTR may,  at its  option,  by notice to 77 WWLP given  within ten (10)
business days after 77 WWLP notifies OTR of such  proceedings  (and if necessary
the Closing  Date shall be extended to give OTR the full ten (10)  business  day
period to make such election):  (i) terminate this Agreement, in which event the
Deposit  shall be  immediately  returned  to OTR,  or (ii)  proceed  under  this
Agreement.  If OTR elects (ii) above, 77 WWLP shall,  at the Closing,  assign to
the LLC its entire right, title and interest in and to any condemnation award in
which event, the LLC shall thereafter  assume  responsibility  for any necessary
repair.  During the  pendency of this  Agreement  OTR and 77 WWLP shall  jointly
negotiate and otherwise  deal with the  condemning  authority in respect of such
matter.  If OTR fails to timely make such election,  OTR shall be deemed to have
elected to terminate this Agreement as provided above.


                                    ARTICLE V

                                     CLOSING

     Section 5.1 CLOSING.  The  consummation  of the  transactions  contemplated
herein  ("Closing")  shall occur on the Closing  Date through an escrow with the
Escrow  Agent at the  offices  of the Escrow  Agent in  Chicago,  Illinois.  The
parties  shall,  and  shall  cause  the  LLC  to,  execute  supplemental  escrow
instructions  as may be appropriate  to enable Escrow Agent to cause  compliance
with  the  terms  of this  Agreement,  so long as such  instructions  are not in
conflict with this Agreement. Such instructions shall provide that if the Escrow
Agent has  authority  from the  other  parties  to  disburse  funds and  deliver
documents of all parties  delivered into escrow with Escrow Agent on the Closing
Date,  the Escrow  Agent  shall  disburse  all such funds and  deliver  all such
documents  concurrently.  The  transactions  described herein shall be closed by
means of concurrent  delivery of the  documents of title,  transfer of interest,
delivery of the Title Policy,  disbursement  of the Loan proceeds and payment of
the OTR Contribution and satisfaction of the Existing Debt, customarily referred
to as a "New York Style" closing.

     Section 5.2 CONDITIONS TO THE PARTIES' OBLIGATIONS TO CLOSE.

          (a) MUTUAL  CONDITIONS.  In addition to all other conditions set forth
     herein,  no party  shall be liable to perform  its  obligations  at Closing
     unless one of the following  conditions is satisfied:  (i) Lender disburses
     the  proceeds  of the  Loan to 77 WWLP  prior  to  Closing  or (ii)  Lender
     disburses the proceeds of the Loan to the LLC at Closing.



                                      -17-
<PAGE>
          (b) OTR CONDITIONS. OTR shall not be liable to perform its obligations
     at Closing unless as of the Closing Date:

               (i) no notice shall have been issued after the  expiration of the
          Due Diligence Period of any violation or alleged violation of any Law,
          including   building  code  (but  excluding  possible  sprinkler  head
          violations,  as to which Section 10.27  applies),  with respect to the
          Property,  the Appurtenances or the Appurtenant  Improvements the cost
          of which  to  correct,  alone or with  other  such  violations  in the
          aggregate,  would  reasonably  exceed  $250,000 and which has not been
          corrected to the satisfaction of the issuer of the notice;

               (ii) at Closing 77 WWLP shall not be in  material  default  under
          any  agreement to be assigned to, or  obligation to be assumed by, the
          LLC under this Agreement;

               (iii)  the  Leases  shall  be in full  force  and  effect  and no
          material  default or claim by landlord  or tenant  shall exist or have
          arisen  under any Leases that was not  specifically  disclosed  in the
          initial Rent Roll and no tenant  leasing space in excess of 10,000 net
          rentable square feet shall have initiated or had initiated  against it
          any insolvency, bankruptcy, receivership or other similar proceeding;

               (iv) the  representations  and  warranties  of 77 WWLP  contained
          herein  shall be true and correct in all  material  respects,  without
          giving effect to Knowledge based qualifications;

               (v) as of the  Closing  Date,  77 WWLP shall have  performed  its
          obligations hereunder; and

               (vi) no  moratorium,  statute,  order,  regulation,  ordinance or
          judgment  of any court or  Governmental  Authority  has been  enacted,
          adopted,  issued or  initiated  since the  Effective  Date that  would
          materially and adversely affect the Property;

               (vii)  the  Property,   the  Appurtenances  and  the  Appurtenant
          Improvements are delivered to the LLC at Closing free and clear of any
          occupants or rights to  possession  other than those of tenants  under
          the Leases, the Loan Documents and the Permitted Exceptions;

               (viii)  the  Title   Company  has  issued  or   irrevocably   and
          unconditionally  committed  to issue the Title Policy  within  fifteen
          (15) days following Closing;

               (ix) 77 WWLP shall have  delivered all other  documents and other
          deliveries required in this Agreement;

               (x) no  circumstance  has  occurred  since  the  end  of the  Due
          Diligence  Period that would  permit OTR to terminate  this  Agreement
          under  Section 4.2 or Section 4.3, as to which Section 4.2 and Section
          4.3, respectively, govern;

               (xi)  77 WWLP  shall  have  entered  into a Lease  of  2,122  net
          rentable  square  feet of space on the 40th floor of the  Improvements
          with  Peregrin  Capital as lessee for a term of five years  commencing
          October 1, 1999 on a net basis at a base rent of $23 per square  foot,
          increasing $1 per square foot on each  anniversary of the commencement
          of the  term  (the  "Peregrin  Lease")  that is  substantially  in the
          standard  form of Lease  included  in the  Property  Information  (the
          "Standard Lease Form");




                                      -18-
<PAGE>
               (xii)  77  WWLP   shall   have   provided   evidence   reasonably
          satisfactory  to OTR that the total  tenant  finish  costs and leasing
          commissions incurred by 77 WWLP for the Peregrin Lease will not exceed
          $40 per  square  foot of net  rentable  area  leased  pursuant  to the
          Peregrin  Lease,  or to the  extent  that the  costs  and  commissions
          incurred by 77 WWLP exceed such  amount,  Prime is legally  obliged to
          indemnify the LLC and hold it harmless from such excess;

               (xiii) 77 WWLP  shall have  entered  into a  modification  of the
          Lease with Zevnik & Horton as lessee  pursuant to which (i) the lessee
          leases an  additional  5,958 square feet of net  rentable  area on the
          33rd floor of the  Improvements  for a term commencing on July 1, 2000
          on a net basis at a base rent of $20 per square foot,  increasing  35?
          per square foot on each  anniversary of the  commencement  of the term
          (the "Z&H  Expansion") and that is substantially in the Standard Lease
          Form;

               (xiv) 77 WWLP shall have  entered  into an extension of the Lease
          with  Zevnik & Horton  pursuant  to  which  the term of such  lease is
          extended from July 1, 2000 through June 30, 2003 at a base rent of $20
          per square foot,  increasing 35? per square foot each July 1 (the "Z&H
          Lease  Extension")  and that is  substantially  in the Standard  Lease
          Form;

               (xv) 77 WWLP shall have provided evidence reasonably satisfactory
          to OTR that no tenant  finish  costs shall be  incurred in  connection
          with  the  Z&H  Expansion  or  the  Z&H  Extension  and  that  leasing
          commissions for the same shall not exceed $2.85 per square foot, or to
          the extent that the costs and  commissions  incurred by 77 WWLP exceed
          such amount, Prime is legally obliged to indemnify the LLC and hold it
          harmless from such excess;

               (xvi) 77 WWLP shall have entered into a  modification  (the "MWBB
          Modification")  of the lease  with  McGuire  Woods  Battle & Booth LLP
          ("MWBB")  pursuant to which the space leased is expanded by 22,617 net
          rentable square feet on the 44th floor of the  Improvements  effective
          February 1, 2000, the term of the lease to MWBB is extended to January
          31, 2010,  the Lease is on a net rent basis,  at a base rent of $21.50
          per square foot,  increasing on each February 1 by 65? per square foot
          and that is substantially in the Standard Lease Form;

               (xvii)  77  WWLP  shall   have   provided   evidence   reasonably
          satisfactory  to OTR that no tenant  finish costs shall be incurred in
          connection with the MWBB Modification and that leasing commissions for
          the costs and commissions shall not exceed $8.55 per square foot or to
          the extent that the same incurred by 77 WWLP exceed such amount, Prime
          is legally obliged to indemnify the LLC and hold it harmless from such
          excess;

               (xviii) 77 WWLP shall have entered into a lease of 3,155 rentable
          square  feet on the 41st  floor of the  Improvements  with  Carvill as
          lessee (the  "Carvill  Lease") for a term of five years  commencing on
          October  1, 1999 on a net basis at a base  rent of $23.00  per  square
          foot,  increasing  75?  per  square  foot  on each  October  1 that is
          substantially in the Standard Lease Form;

               (xix)  77  WWLP   shall   have   provided   evidence   reasonably
          satisfactory  to OTR that tenant finish costs and leasing  commissions
          incurred  for the  Carvill  Lease  shall not exceed  $13.94 per square
          foot, or, to the extent that the costs and commissions  incurred by 77
          WWLP exceed such  amount,  that Prime is legally  obliged to indemnify
          and hold harmless the LLC from such excess;


                                      -19-
<PAGE>
               (xx) 77 WWLP shall have entered into alternate  arrangements  for
          the  sub-leasing of the space demised to it pursuant to the Air Rights
          Lease  satisfactory  to OTR so that OTR  shall not  receive  unrelated
          business income in connection with such space;

               (xxi) 77 WWLP shall cause Prime to  undertake  liability  for and
          indemnify the LLC against the  obligations of 77 WWLP under Section 29
          of the  Lease  to  Jones  Day  Reavis  & Pogue  LLP  ("Jones  Day") to
          indemnify Jones Day against  liability in connection with its lease of
          space at 225 West Washington Street, Chicago, Illinois;

               (xxii) good,  indefeasible,  marketable  and insurable fee simple
          absolute title to the Property,  free, clear and  unencumbered  except
          for the  Permitted  Exceptions,  and  otherwise on the terms set forth
          herein,  shall have  vested in the LLC or been  tendered by 77 WWLP to
          the LLC;

               (xxiii) good, marketable and insurable title to the Appurtenances
          and the Appurtenant Improvements,  free, clear and unencumbered except
          for the Permitted  Exceptions  (including  any Permitted  Appurtenance
          Liens as defined in Section 3.4) and  otherwise on the terms set forth
          herein shall have vested in the LLC or been tendered by 77 WWLP to the
          LLC; and

               (xxiv) all other  conditions to OTR's  obligations  to proceed to
          Closing which are set forth in this Agreement are satisfied.

          (c) 77 WWLP  CONDITIONS.  77 WWLP shall not be liable to  perform  its
     obligations at Closing unless, as of the Closing Date:

               (i) all of OTR's  representations  and  warranties  hereunder are
          true and correct in all material respects;

               (ii) OTR has performed all of its covenants hereunder required to
          be performed on or before Closing;

               (iii) OTR has tendered payment of the OTR Contribution;

               (iv)  OTR  has  delivered  all  documents  and  other  deliveries
          required of it under this Agreement; and

               (v) no notice shall have been issued after the  expiration of the
          Due Diligence Period of any violation or alleged violation of any law,
          including  building  codes  (but  excluding  possible  sprinkler  head
          violations,  as to which Section 10.27 applies),  the cost of which to
          correct,  alone or with other such violations in the aggregate,  would
          reasonably  exceed  $250,000,  except  that  in no  event  shall  this
          condition  apply  in the  case  of any  such  violation  that  77 WWLP
          intentionally caused to occur;

               (vi) OTR has  authorized the LLC to distribute to or on behalf of
          77 WWLP (A) the amount provided in Section 2.9 and (B) an amount,  not
          in excess of the sum of (I) the principal  amount of $170,000,000  and
          (II) an amount equal to one month of interest on the Existing Debt, in
          order to satisfy the Existing Debt in full;

               (vii) no moratorium,  statute,  order,  regulation,  ordinance or
          judgment  of any court or  Governmental  Authority  has been  enacted,
          adopted,  issued or  initiated  since the  Effective  Date that  would
          materially and adversely affect the Property; and

               (viii) all other  conditions to 77 WWLP's  obligations to proceed
          to Closing which are set forth in this Agreement are satisfied.

                                      -20-
<PAGE>

          (d) APPROVAL OF PRIME LENDERS. Neither 77 WWLP nor OTR shall be liable
     to perform their respective  obligations at Closing if 77 WWLP gives notice
     to OTR that 77 WWLP has been  unable to obtain  approval  on or before  the
     fourteenth (14th) day following  execution of this Agreement of the lenders
     providing a line of credit to Prime or Prime Group Realty Trust, a Maryland
     real estate investment trust (the "REIT"), to the transaction  contemplated
     by this  Agreement,  and 77 WWLP  gives  notice  to OTR  prior  to 5:00 pm,
     Central  Daylight  Time  within  such  fourteen  (14) day period  that such
     lenders have not so approved such  transaction.  If such notice is given or
     if this Agreement  terminates pursuant to Section 2.6, the last grammatical
     paragraph of Section 3.1 or Section  3.7, (i) the Deposit  shall be paid to
     OTR,  and (ii) 77 WWLP shall pay to OTR the lesser of (A)  $100,000 and (B)
     the aggregate amount of costs and expenses incurred by OTR to third parties
     in connection with negotiating  this Agreement,  performing its obligations
     under it and  exercising its rights and powers under it (the "Due Diligence
     Expenses").  77 WWLP shall pay such  amount to OTR within  thirty (30) days
     following OTR's furnishing to 77 WWLP of evidence reasonably substantiating
     the incurring of Due Diligence Expenses.

          (e) FAILURE OF CONDITION.  So long as a party is not in default in the
     performance of any obligation  hereunder,  if any condition to such party's
     obligation to perform  obligations  at Closing set forth in this  Agreement
     has not been satisfied as of the Closing Date,  such party may, in its sole
     discretion,  (i) terminate this Agreement,  by delivering written notice to
     the other parties on or before the Closing  Date,  (ii) elect to extend the
     time available for the  satisfaction  of such condition by up to a total of
     10 business  days or (iii)  elect on or before the  Closing  Date to close,
     notwithstanding the non-satisfaction of such condition, in which event such
     party  shall be deemed to have  waived  any such  condition.  If such party
     elects to proceed pursuant to clause (ii) above, and such condition remains
     unsatisfied  after the end of such  extension  period,  then, at such time,
     such  party may elect to  proceed  pursuant  to either  clause (i) or (iii)
     above.  Any failure to timely elect to proceed  under  clauses (i), (ii) or
     (iii) above, shall be deemed an election to proceed under clause (i) above.
     In the event of a termination  pursuant to this section,  the Deposit shall
     be returned to OTR.

     Section 5.3  DELIVERIES  BY 77 WWLP IN ESCROW.  At least one  business  day
prior to the Closing  Date,  77 WWLP shall deliver in escrow to the Escrow Agent
or outside of escrow to OTR the following and in the case of the following  that
are documents, each duly executed and, where appropriate, in recordable form and
notarized:

          (a)  OPERATING  AGREEMENT.  A counterpart  of the Operating  Agreement
     executed by Prime;

          (b) DEED. A special  warranty deed  substantially in the form attached
     hereto  as  Appendix   5.3(b)  and   incorporated   herein,   executed  and
     acknowledged  by 77 WWLP in its individual  capacity,  conveying to the LLC
     good,  indefeasible,  marketable and insurable fee absolute simple title to
     the Real Property, subject only to the Permitted Exceptions (the "Deed");

          (c) BILL OF SALE AND ASSIGNMENT. A counterpart of the Bill of Sale and
     Assignment   in  the  form  of  Appendix   5.3(c)   attached   hereto  (the
     "Assignment"),  executed  and  acknowledged  by 77 WWLP  in its  individual
     capacity  vesting in the LLC good title to the property  described  therein
     free of any claims except for Permitted Exceptions;

          (d) NOTICE TO TENANTS AND VENDORS. A notice to each tenant in the form
     attached as Appendix 5.3(d) attached hereto and incorporated herein as well
     as a notice to each vendor under the Service Contracts in the form attached
     as Appendix 5.3(d) attached hereto and incorporated herein;

                                      -21-
<PAGE>
          (e)  STATE  LAW  DISCLOSURES.  Such  disclosures  and  reports  as are
     required  by  applicable  state  and  local  law  in  connection  with  the
     conveyance of real property;

          (f)  FIRPTA.  An  affidavit  of  77  WWLP  (the  "FIRPTA   Affidavit")
     substantially   in  the  form  of  Appendix   5.3(f)  attached  hereto  and
     incorporated  herein.  If 77 WWLP fails to provide the necessary  affidavit
     and/or  documentation  of  exemption  on the  Closing  Date,  the LLC shall
     proceed in accordance  with the withholding  provisions  imposed by Section
     1445 of the Internal Revenue Code of 1986, as amended;

          (g) TENANT  ESTOPPELS.  Tenant Estoppels  satisfying the conditions in
     Section 3.7;

          (h) GROUND LESSOR'S ESTOPPEL. The ground lessor's estoppel as provided
     in Section 3.8;

          (i) AUTHORITY.  Evidence of the existence,  organization and authority
     of 77 WWLP and of the  authority  of the  persons  executing  documents  on
     behalf of 77 WWLP reasonably  satisfactory to OTR, the Escrow Agent and the
     Title Company;

          (j) DELINQUENT TAX LETTER  AGREEMENT.  A counterpart of the Delinquent
     Tax Letter Agreement.

          (k) TITLE DOCUMENTS. The documents specified in Appendix 2.7(3);

          (l) PRIME UNDERTAKING.  An undertaking in writing executed by Prime in
     favor of the LLC and OTR, reasonably satisfactory to OTR, pursuant to which
     Prime  agrees to perform  those  obligations  of 77 WWLP that  survive  the
     Closing,  including without  limitation,  the obligations of 77 WWLP (i) to
     satisfy in full the  Existing  Indebtedness  and to obtain a release of the
     Existing  Mortgage as provided in Section 2.8 herein,  (ii) provided in the
     Delinquent Tax Letter  Agreement,  (iii) to pay Leasing  Commissions and TI
     Obligations  as provided in  Sections  6.1(e) and 6.10 herein and,  (iv) if
     required in Section 10.27,  to replace  sprinkler  heads at the Property as
     provided in Section 10.27 herein;

          (m) MANAGEMENT  AGREEMENT.  A counterpart of the Management  Agreement
     executed by the Manager;

          (n)  OPINION.   the  opinion  of  Winston  &  Strawn  as  to  the  due
     authorization  and execution by 77 WWLP of the  documents  that 77 WWLP are
     required by this  Agreement to deliver that is reasonably  satisfactory  to
     OTR; and

          (o)  OTHER   DELIVERIES.   Such  other  documents,   certificates  and
     instruments  reasonably  necessary  in order  to  effect  the  transactions
     described herein, including without limitation,  transfer tax declarations,
     broker lien waivers,  bulk sale  clearances and any documents  necessary to
     comply with any applicable  environmental  transfer disclosure laws and any
     other Closing deliveries  required to be made by or on behalf of 77 WWLP as
     provided in this Agreement.

     Section  5.4  OTR'S  DELIVERIES  IN  ESCROW.  (a)  Documents.  At least one
business  day prior to the  Closing  Date,  OTR shall  deliver  in escrow to the
Escrow Agent or outside of escrow to Prime or 77 WWLP the  following,  each duly
executed and, where appropriate, in recordable form and notarized:

               (i) OPERATING AGREEMENT. A counterpart of the Operating Agreement
          executed by OTR;



                                      -22-
<PAGE>
               (ii)  DELINQUENT  TAX  LETTER  AGREEMENT.  A  counterpart  of the
          Delinquent Tax Letter Agreement;

               (iii) OPINION. The opinion of Taft, Stettinius & Hollister LLP as
          to the due  authorization  and execution by OTR of the documents  that
          OTR is  required  by this  Agreement  to  deliver  that is  reasonably
          satisfactory to 77 WWLP; and

               (iv) OTHER  DELIVERIES.  Such other  documents,  certificates and
          instruments  reasonably  necessary in order to effect the  transaction
          described herein and any other closing deliveries  required to be made
          by or on behalf of OTR as provided in this Agreement.

          (b) FUNDS.  On the Closing  Date,  OTR shall  deliver in escrow to the
     Escrow Agent the OTR Contribution.

     Section 5.5 LLC'S  DELIVERIES IN ESCROW.  (a) Except as specified below, at
least one business day prior to the Closing Date,  each of 77 WWLP and OTR shall
or if Prime is or shall be a member of the LLC,  as of  Closing,  77 WWLP  shall
cause Prime to, and OTR shall,  execute counterparts of the following as members
on behalf of the LLC and shall deliver them in escrow to the Escrow Agent:

               (i) LOAN  DOCUMENTS.  The Loan  Documents in the form required by
          Lender and approved by OTR and 77 WWLP,  unless the Loan Documents are
          executed and delivered prior to Closing, in which event, an assumption
          of the Loan  Documents,  if any,  required  by Lender  and  reasonably
          satisfactory  to OTR  and 77  WWLP,  except  that  if  this  Agreement
          terminates  pursuant to Section  2.6  hereof,  neither OTR nor 77 WWLP
          shall have any such obligation;

               (ii) BILL OF SALE AND ASSIGNMENT. Counterpart of Bill of Sale and
          Assignment;

               (iii) STATE LAW DISCLOSURES.  Such disclosures and reports as are
          required  by  applicable  state and local law in  connection  with the
          conveyance of real property;

               (iv)  MANAGEMENT  AGREEMENT.  A  counterpart  of  the  Management
          Agreement; and

               (v) OTHER  DELIVERIES.  Such other  documents,  certificates  and
          instruments  reasonably  necessary in order to effect the transactions
          described  herein,  including  any documents  reasonably  necessary to
          cause the Title  Company to issue a loan policy of title  insurance to
          Lender insuring the lien of the Loan Documents  (except that OTR shall
          not be obliged to sign any counterpart of any such document).

          (b) FUNDS.  On the Closing Date,  OTR and 77 WWLP shall each authorize
     and empower  the LLC to deliver  the  proceeds of the Loan in escrow to the
     Escrow  Agent to the extent not already  delivered  in escrow to the Escrow
     Agent by Lender.

     Section  5.6 CLOSING  STATEMENTS.  At least one  business  day prior to the
Closing  Date,  77 WWLP and OTR shall  deposit  with the  Escrow  Agent  closing
statements for the Property  consistent with this Agreement  executed by 77 WWLP
in its individual capacity and by 77 WWLP and OTR on behalf of the LLC.

     Section 5.7 POSSESSION.  77 WWLP shall deliver  possession of the Property,
the Appurtenances and the Appurtenant Improvements to the LLC at the Closing.





                                      -23-
<PAGE>
     Section 5.8  DELIVERY  OF BOOKS AND  RECORDS.  Pursuant  to the  Management
Agreement, subsequent to Closing, Prime shall retain at its offices the original
documents and instruments assigned to the LLC pursuant to the Assignment; copies
or originals of all books and records of account,  copies of correspondence with
tenants and suppliers,  receipts for deposits,  unpaid bills and other papers or
documents that pertain to the Property,  the  Appurtenances  or the  Appurtenant
Improvements; all advertising materials, booklets, keys and other items, if any,
pertaining to the Property,  the Appurtenances or the Appurtenant  Improvements;
and,  if in the  possession  or  control  of  Prime  or 77  WWLP,  the  original
"as-built"  plans  and   specifications   and  all  other  available  plans  and
specifications.

                                   ARTICLE VI

                                PRORATIONS; COSTS

     Section  6.1  PRORATIONS.  Not less than three (3)  business  days prior to
Closing,  77  WWLP  shall  provide  to OTR  such  information  and  verification
reasonably necessary to support the prorations under this Section 6.1. The items
in this  Section  6.1 shall be  prorated  between  77 WWLP and the LLC as of the
close of business on the day immediately preceding the Closing Date, the Closing
Date being a day of income and  expense to the LLC. 77 WWLP shall pay to the LLC
at Closing the amount, if any, by which credits in favor of the LLC shall exceed
credits in favor of 77 WWLP. 77 WWLP and OTR shall authorize and empower the LLC
at Closing to pay to 77 WWLP at Closing the amount,  if any, by which credits in
favor of 77 WWLP shall exceed credits in favor of the LLC.

          (a) TAXES AND ASSESSMENTS.  OTR and 77 WWLP acknowledge and agree that
     the tenants are obliged  under the Leases to pay  substantially  all of any
     accrued but unpaid ad valorem real property taxes and assessments ("Taxes")
     in accordance with the Leases.  Accordingly, no adjustment shall be made in
     respect of such Taxes incurred by LLC or 77 WWLP.

          (b) COLLECTED RENT. At Closing, any Rent and other income under Leases
     collected  by 77 WWLP  before  Closing  that  applies to any  period  after
     Closing  shall be  prorated  so that the LLC shall  receive a credit in the
     amount  equal to the product of such Rent and other  income and a fraction,
     the numerator of which is the number of days in the period  covered by such
     payment from and after the day of Closing and the  denominator  of which is
     the total number of days in the period covered by such payment. Uncollected
     rent and other uncollected  income shall not be prorated at Closing.  After
     Closing,  77 WWLP and OTR shall  cause the LLC to apply all rent and income
     collected  by the LLC from a tenant,  whether  through a normal  collection
     effort,  litigation,  or otherwise,  first to such tenant's current monthly
     rental and then to  arrearages in the reverse order in which they were due,
     remitting  to 77  WWLP,  after  deducting  collection  costs,  any  balance
     properly allocable to 77 WWLP's period of ownership.  77 WWLP and OTR shall
     authorize,  empower  and  direct  the  LLC to  bill  and  use  commercially
     reasonable  efforts to collect such rent  arrearages in the ordinary course
     of business,  but the LLC need not engage a collection agency or take legal
     action to collect any rent arrearages.  77 WWLP shall not have the right to
     seek  collection  of any rents or other  income  applicable  to any  period
     before the Closing,  except that 77 WWLP may use collection efforts against
     Cafe Baci that do not involve  litigation or interference  with Cafe Baci's
     possession of the space currently  leased to it at the Property.  Except as
     otherwise  provided  in this  Section  6.1(b),  any  Rents or other  income
     received by 77 WWLP after  Closing  which are owed to the LLC shall be held
     in trust and remitted to the LLC promptly  after receipt for allocation and
     disbursement  as  provided in this  Section  6.1.  Any Rents or  settlement
     amounts received by 77 WWLP or the LLC from Cafe Baci for a period prior to
     Closing belong to 77 WWLP.



                                      -24-
<PAGE>
          (c) OPERATING EXPENSE PASS-THROUGHS.  This subparagraph shall apply to
     any  additional  rent  (collectively,  "Operating  Expense  Pass-Throughs")
     payable under the Leases to cover taxes, insurance, utilities,  maintenance
     and other operating costs and expenses (collectively  "Operating Expenses")
     incurred by the owner of the  Property in  connection  with the  ownership,
     operation,  maintenance  and  management of the  Property.  OTR and 77 WWLP
     acknowledge  and agree that the tenants at the Property  are obliged  under
     the Leases to pay substantially all of the Operating Expenses in accordance
     with the Leases.  Accordingly,  no  adjustment  shall be made in respect of
     Operating Expenses incurred by the LLC or 77 WWLP, and, at Closing, 77 WWLP
     shall pay to the LLC an amount  equal to the  amount of  Operating  Expense
     Pass-throughs  that it has collected  prior to Closing that it has not used
     to pay Operating Expenses prior to Closing.

          (d) TENANT DEPOSITS. At Closing, 77 WWLP shall transfer to the LLC all
     tenant  security  deposits  (and  interest  thereon if  required  by law or
     contract to be earned thereon). At Closing, 77 WWLP shall initiate transfer
     to the LLC of any letters of credit  furnished as tenant security  deposits
     and  thereafter  diligently  pursue such transfer.  As of Closing,  the LLC
     shall assume 77 WWLP's obligations related to tenant security deposits, but
     only to the extent that they are  transferred  as provided in this  Section
     6.1(d).

          (e)  LEASING  COMMISSIONS.  On or before the date that the same become
     due and  payable,  77 WWLP  shall  pay in full  those  leasing  commissions
     specified in Appendix 6.1(e) attached hereto and  incorporated  herein that
     77 WWLP is to pay.  Leasing  commissions  arising  in  connection  with any
     renewal or expansion  rights  under  Leases that are  properly  exercisable
     after the date of this Agreement and disclosed in the Commission  Schedule,
     if any, shall be the LLC's obligation to pay as and when due. The LLC shall
     pay these  leasing  commissions  specified  in Exhibit A that the LLC is to
     pay.

          (f) OTHER REVENUES AND INCOME AND OTHER EXPENSES.  At Closing, any and
     all revenues and income in  connection  with the operation at the Property,
     the Appurtenances or the Appurtenant  Improvements not otherwise covered in
     this Article VI and collected by or on behalf of 77 WWLP before the Closing
     and applicable to the LLC's period of ownership  shall be prorated  between
     77 WWLP and the LLC so that 77 WWLP  receives  the same to the extent  they
     accrued and are  allocable  with respect to the period of its  ownership of
     the  Property and the LLC receives the same to the extent that they accrued
     and are  allocable  with  respect  to the  period of its  ownership  of the
     Property,  the Appurtenances or the Appurtenant  Improvements.  At Closing,
     any and all expenses in  connection  with the operation of the Property the
     Appurtenances  or the  Appurtenant  Improvements  paid  by 77  WWLP  before
     Closing,  not otherwise  covered in this Article VI, and  applicable to the
     LLC's  period  of  ownership  of the  Property,  the  Appurtenances  or the
     Appurtenant  Improvements shall be prorated between 77 WWLP so that 77 WWLP
     pays for such expenses to the extent that they accrued and are allocable to
     the period of its  ownership  of the  Property,  the  Appurtenances  or the
     Appurtenant  Improvements  and the LLC pays for such expenses to the extent
     that they  accrued  and are  allocable  with  respect  to the period of its
     ownership  of  the  Property,   the   Appurtenances   or  the   Appurtenant
     Improvements.  If any such amount  cannot be  determined  at Closing,  such
     payment  shall be based upon an estimate.  In  addition,  (i) 77 WWLP shall
     promptly  remit or cause to be  remitted to the LLC any such  revenues  and
     income  not  covered  in this  Article  VI and  collected  by 77 WWLP after
     Closing that are  applicable to the LLC's period of ownership,  and (ii) 77
     WWLP and OTR shall authorize,  empower and direct the LLC to remit or cause
     to be remitted to 77 WWLP such revenues and income not otherwise covered in
     this Article VI collected by the LLC after  Closing that are  applicable to
     77 WWLP's period of ownership.  In addition,  77 WWLP shall pay its prorata


                                      -25-
<PAGE>
     share  of any  such  expenses  in  connection  with  the  operation  of the
     Property,  the Appurtenances or the Appurtenant  Improvements not otherwise
     covered by this Article VI within ten (10) days  following  written  notice
     from the LLC that such  amount is due to the  extent  that the LLC pays for
     any such expense that is applicable to 77 WWLP's period of ownership.

          (g)  INTEREST  ON THE DEBT.  Interest  accrued  and unpaid on the Debt
     prior to Closing  shall be a credit in favor of the LLC.  Interest  paid on
     the Debt prior to Closing with respect to the day of Closing and thereafter
     shall be a credit in favor of 77 WWLP.

     Section 6.2 POST-CLOSING CORRECTIONS.  77 WWLP, in its individual capacity,
on the one hand, and the LLC, on the other,  shall be entitled to a post-Closing
adjustment for any incorrect proration or adjustment, whether made at Closing or
within one year thereafter,  including any payments or adjustments made pursuant
to this Article VI, provided such adjustment is claimed by such party within one
year after  Closing.  No expense  related to the  ownership  or operation of the
Property, the Appurtenances or the Appurtenant  Improvements shall be charged to
or paid or  assumed  by OTR or the LLC under  this  Agreement,  other than those
obligations expressly assumed by the LLC.

     Section  6.3  UTILITIES.  OTR and 77 WWLP  acknowledge  and agree  that the
tenants  are  obliged  under  the  Leases  to pay for  substantially  all of the
utilities  consumed at the Property in accordance with the Leases.  Accordingly,
no adjustment shall be made in respect of the expense of such utilities incurred
by the LLC or 77 WWLP.

     Section 6.4 SERVICE  CONTRACTS.  OTR and 77 WWLP acknowledge and agree that
the tenants are obliged under the Leases to pay substantially all of the charges
incurred  by 77 WWLP under  Service  Contracts  in  accordance  with the Leases.
Accordingly,  no adjustment shall be made in respect of the expenses incurred by
the LLC or 77 WWLP under the Service Contracts.

     Section 6.5 COSTS.  OTR shall pay (i) one-half of the Escrow Agent?s escrow
fee,  closing  charges,  and any  cancellation  fee,  (ii) the cost of the Title
Policy  and the  Endorsements,  and (iii) the costs  associated  with  OTR's due
diligence  activities.  77 WWLP shall pay (i)  one-half  of the  Escrow  Agent's
escrow fee,  closing  charges  and any  cancellation  fee,  (ii) the cost of the
Survey,  and (iii) all recording  fees or other  charges  incurred in connection
with the recording of the Deed and clearing title,  including without limitation
any  prepayment or release  fees.  Each party shall be  responsible  for its own
attorney's and other professional fees.

     Section 6.6 SALES,  TRANSFER,  AND DOCUMENTARY TAXES. 77 WWLP shall pay all
sales, gross receipts, compensating, stamp, excise, documentary,  transfer, deed
or similar  taxes and fees imposed in  connection  with this  transaction  under
applicable state, county or local Law. 77 WWLP in its individual capacity shall,
and 77 WWLP or Prime and OTR, as members of the LLC,  shall  authorize,  empower
and direct the LLC to execute any applicable city, county and state transfer tax
returns or other declarations.

     Section 6.7 UTILITY DEPOSITS.  77 WWLP shall transfer to the LLC at Closing
any deposits with utility companies that are transferable.

     Section 6.8 SALES  COMMISSIONS.  77 WWLP, on the one hand,  and OTR, on the
other, represent and warrant each to the other that they have not dealt with any
real estate broker,  sales person or finder in connection with this  transaction
other than Brokers.  If Closing occurs,  77 WWLP shall pay Brokers in accordance
with its separate  agreement with Brokers.  Brokers are independent  contractors
and are not  authorized  to make any  agreement or  representation  on behalf of
either party. Except as expressly set forth above, in the event of any claim for
broker's or finder's fees or  commissions  in connection  with the  negotiation,


                                      -26-
<PAGE>
execution or  consummation  of this Agreement or the  transactions  contemplated
hereby,  each party shall indemnify,  defend and hold harmless the other parties
from and  against  any such claim  based  upon any actual or alleged  statement,
representation  or agreement of such party.  This  provision  shall  survive any
termination of this Agreement and the Closing.

     Section 6.9 WAGES. Intentionally deleted.

     Section  6.10  TENANT  IMPROVEMENTS  AND  ALLOWANCES.   Tenant  improvement
expenses (including all hard and soft construction costs, whether payable to the
contractor  or  the  tenant),  tenant  allowances,  moving  expenses  and  other
out-of-pocket  costs that are the  obligation of the landlord  under Leases ("TI
Obligations") shall be allocated between 77 WWLP, in its individual capacity, on
the one hand,  and the LLC, on the other hand, in  accordance  with this Section
6.10.

          (a) EXISTING TI OBLIGATIONS. 77 WWLP shall pay all TI Obligations that
     are specified as obligations of 77 WWLP in Appendix 6.10(a) attached hereto
     and  incorporated  herein to the obligee of such TI Obligations as and when
     the same are due.

          (b) OTHER TI  OBLIGATIONS.  The LLC shall pay all TI Obligations  that
     are specified as obligations of the LLC in Appendix 6.10(b) attached hereto
     and  incorporated  herein to the obligee of such TI Obligations as and when
     the same are due.

          (c) Intentionally deleted.

          (d) ASSIGNMENT OF CONTRACTS. If tenant improvement work required under
     any Lease is not complete at Closing,  77 WWLP shall at Closing  assign the
     architect, contractor and other agreements relating to such improvements to
     the  LLC,  and the LLC  shall  assume  obligations  under  such  agreements
     occurring from and after Closing, except for payment obligations of 77 WWLP
     set  forth  in  Section  6.10(a).  Such  assignment  shall  be in form  and
     substance reasonably acceptable to OTR and shall be accompanied by consents
     to such assignment from the parties obligated under such agreements.

          (e) CHANGE  ORDERS.  77 WWLP  shall not agree to any change  orders or
     additions  to  tenant  improvements  or  changes  in the  scope  of work or
     specifications  with  respect to TI  Obligations  that the LLC must  assume
     under  Section  6.1(d)   without  OTR's  prior  written   approval  if  (i)
     modification  of the  Lease  to which  such TI  Obligations  pertain  would
     require OTR's approval under this Agreement or (ii) such modification would
     require OTR's approval under the Operating  Agreement,  if the same were in
     effect.

                                   ARTICLE VII

                         REPRESENTATIONS AND WARRANTIES

     Section  7.1  REPRESENTATIONS  AND  WARRANTIES  OF 77 WWLP.  As a  material
inducement to OTR to execute this Agreement and consummate this transaction,  77
WWLP represents and warrants to OTR that:

          (a) ORGANIZATION AND AUTHORITY. 77 WWLP has been duly organized and is
     validly  existing  under the laws of the state under which it is organized,
     and is in good standing and  qualified to do business in Illinois.  77 WWLP
     has the full right and authority and, except as provided in Section 5.2(d),
     has obtained any and all  consents  required to enter into this  Agreement,
     all of the  documents  to be  delivered  by 77 WWLP at the  Closing  and to
     consummate or cause to be consummated the transactions contemplated hereby.
     At Closing,  77 WWLP shall have  obtained any and all consents  required to


                                      -27-
<PAGE>
     enter this  Agreement,  all of the  documents to be delivered by 77 WWLP at
     the Closing and to consummate or cause to be consummated  the  transactions
     contemplated  hereby.  This Agreement has been, and all of the documents to
     be  delivered by 77 WWLP at the Closing  will be,  authorized  and properly
     executed and constitute, or will constitute, as appropriate,  the valid and
     binding obligation of 77 WWLP, enforceable in accordance with their terms.

          (b)  CONFLICTS  AND  PENDING  ACTIONS  OR  PROCEEDINGS.  There  is  no
     agreement  to which  either 77 WWLP is a party or, to the  Knowledge  of 77
     WWLP,  which is binding on 77 WWLP which is in conflict with this Agreement
     other than the  Existing  Mortgage  or as provided  in Section  5.2(d).  At
     Closing, there shall be no agreement to which 77 WWLP is a party, or to the
     Knowledge of 77 WWLP which is binding on 77 WWLP which is in conflict  with
     this  Agreement.  Except as disclosed in the  Property  Information  or the
     Supplemental Property Information, there is no action or proceeding pending
     or,  to 77 WWLP's  Knowledge,  threatened  in  writing  against  77 WWLP or
     relating  to  the   Property,   the   Appurtenances   or  the   Appurtenant
     Improvements,  and no basis exists for any such action or proceeding to the
     extent  that the same could  result in a claim  against  the LLC or a claim
     against the Property,  the  Appurtenances  or the Appurtenant  Improvements
     sounding in contract  (as opposed to tort).  77 WWLP has not  received  any
     written notice that any condemnation, eminent domain or similar proceedings
     are pending or threatened with regard to the Property, the Appurtenances or
     the Appurtenant Improvements.  Except as disclosed in the Title Commitment,
     77 WWLP has not received any written notice and has no Knowledge of (i) any
     pending or threatened Liens,  special assessments or impositions to be made
     against the Property, (ii) any pending or threatened special assessments or
     impositions  to be  made  against  the  Appurtenances  or  the  Appurtenant
     Improvements that would not be subordinate to the rights of 77 WWLP therein
     (other than the lien of taxes not yet due and payable),  or (iii) any liens
     against the Appurtenances or the Appurtenant Improvements that would not be
     subordinate  to the rights of 77 WWLP therein (other than the lien of taxes
     not yet due and payable or as may be set forth in Appendix 2.7(2)).

          (c) LEASES.  The documents  constituting the Leases that are delivered
     to OTR pursuant to Section 3.2 are true, correct and complete copies of all
     of the Leases affecting the Property,  the Appurtenances or the Appurtenant
     Improvements including any and all amendments and guarantees. Except as set
     forth in the Property  Information,  the Supplemental  Property Information
     and Appendix 6.1(e), there are no leasing or other fees or commissions due,
     nor will any become  due,  in  connection  with any Lease or any renewal or
     extension or expansion of any Lease, and no understanding or agreement with
     any party exists as to payment of any leasing commissions or fees regarding
     future leases or as to the procuring of tenants. To 77 WWLP's Knowledge the
     Leases are in full force and effect.  Neither 77 WWLP nor, to the Knowledge
     of 77 WWLP and except as disclosed in Appendix  7.1(c)  attached hereto and
     incorporated  herein or in the Tenant Estoppels,  are 77 WWLP or any of the
     tenants in default under the Leases. To the Knowledge of 77 WWLP, except as
     disclosed in Appendix 7.1(c) attached hereto and incorporated herein or the
     Tenant  Estoppels,  no tenants have  asserted nor are there any defenses or
     offsets to rent  accruing  after the Closing  Date.  Except as set forth in
     Appendix 6.10(a),  Appendix 6.10(b) and Appendix 7.1(c) attached hereto and
     incorporated herein, all of the landlord's  obligations to construct tenant
     improvements  or reimburse  the tenants for tenant  improvements  under the
     Leases have been paid and performed in full, and except as set forth in the
     Leases or the Tenant Estoppels,  all concessions  (other than any unexpired
     rent  abatement set forth in the Leases) from the landlord under the Leases
     have been paid and performed in full.  Except for the Existing Mortgage and
     collateral  assignments  being fully  released at Closing,  77 WWLP has not
     assigned or pledged the Leases or Rents or any interest therein.




                                      -28-
<PAGE>
          (d) SERVICE CONTRACTS.  The list of Service Contracts delivered to OTR
     pursuant to this Agreement is true,  correct,  and complete as of its date.
     The documents  constituting the Service Contracts that are delivered to OTR
     as a part of the initial Property Information and the Supplemental Property
     Information  are true,  correct  and  complete  copies  of all the  Service
     Contracts  affecting the Property,  the  Appurtenances  or the  Appurtenant
     Improvements.  Neither 77 WWLP nor, to the Knowledge of 77 WWLP,  any other
     party is in material default under any Service Contract.

          (e) FINANCIAL  STATEMENTS.  The Financial  Statements delivered to OTR
     pursuant to this Agreement show all items of income and expense  (operating
     and capital)  incurred in connection  with the  ownership,  operation,  and
     management  of  the  Property,   the   Appurtenances  and  the  Appurtenant
     Improvements for the periods indicated and are true, correct,  and complete
     in all material respects.

          (f)  PERMITS,  LEGAL  COMPLIANCE,   AND  NOTICE  OF  DEFECTS.  To  its
     Knowledge, 77 WWLP has all licenses, permits and certificates necessary for
     the  use  and  operation  of  the  Property,   the  Appurtenances  and  the
     Appurtenant Improvements including, without limitation, all certificates of
     occupancy  necessary for the occupancy of the Property,  the  Appurtenances
     and the Appurtenant Improvements all of which are in full force and effect.
     77 WWLP has not taken or failed to take any  action  that  would  result in
     their revocation,  or received any written notice of an intention to revoke
     any of  them.  To the  Knowledge  of 77 WWLP,  neither  the  Property,  the
     Appurtenances or the Appurtenant  Improvements nor the use thereof violates
     any Law or any covenants or  restrictions  encumbering  the  Property,  the
     Appurtenances or the Appurtenant Improvements. To the Knowledge of 77 WWLP,
     except  as  disclosed  in the  Property  Information  and the  Supplemental
     Property  Information,  there  are  no  material  physical  defects  in the
     Improvements or the Appurtenant Improvements. Except to the extent, if any,
     specified  in  the  Property  Information  or  the  Supplemental   Property
     Information, 77 WWLP has not received any written notice from any insurance
     company or  underwriter  and has no  Knowledge  of any  defects  that would
     materially   adversely  affect  the  insurability  of  the  Property,   the
     Appurtenances  or the  Appurtenant  Improvements  or cause an  increase  in
     insurance  premiums.  77 WWLP  has not  received  written  notice  from any
     Governmental  Authority  or other  person of, and has no  Knowledge  of any
     violation of zoning, building, fire, health, environmental,  Law (including
     those respecting the Americans with Disabilities  Act), or any restriction,
     condition, covenant or consent in regard to the Property, the Appurtenances
     or the  Appurtenant  Improvements  or any part thereof  which have not been
     corrected to the satisfaction of such Governmental Authority.

          (g) ENVIRONMENTAL. 77 WWLP has no Knowledge of the presence or Release
     of Hazardous  Materials on or from the Property,  the  Appurtenances or the
     Appurtenant  Improvements  such that applicable  Environmental Law requires
     the remedy of the effect on the environment of such presence or release, or
     of any  violation  of  Environmental  Laws  related  to the  Property,  the
     Appurtenances or the Appurtenant Improvements. To the Knowledge of 77 WWLP,
     no tenant or other  occupant  has  manufactured,  introduced,  Released  or
     discharged from or onto the Property,  the Appurtenances or the Appurtenant
     Improvements any Hazardous Materials such that applicable Environmental Law
     requires the remedy of the effect on the  environment  of the same.  To the
     Knowledge of 77 WWLP,  no tenant or other  occupant has used the  Property,
     the  Appurtenances or the Appurtenant  Improvements or any part thereof for
     the generation,  treatment,  storage, handling or disposal of any Hazardous
     Materials such that applicable Environmental Law requires the remedy of the
     effect on the  environment of the same.  There are no  underground  storage
     tanks  located  on the  Property,  the  Appurtenances  or  the  Appurtenant
     Improvements.  77 WWLP has  furnished  to OTR a true,  correct and complete
     copy of all  Environmental  Assessments  and/or  studies  pertaining to the


                                      -29-
<PAGE>
     Property,  the  Appurtenances  or  the  Appurtenant   Improvements  in  the
     possession or control of either. To the Knowledge of 77 WWLP, no additional
     environmental  assessments  or studies  exist with respect to the Property,
     the Appurtenances or the Appurtenant Improvements.

          (h) DISCLOSURE.  Other than this Agreement, the documents delivered at
     Closing pursuant hereto, the Permitted  Exceptions,  the Service Contracts,
     the Leases,  the Air Rights Lease,  the Parking  Agreement,  the agreements
     pertaining  to the  health  club in the Air  Rights  Parcel  and any  other
     contracts  or  agreements  included  in  the  Property  Information  or the
     Supplemental Property Information,  there are no contracts or agreements of
     any kind relating to the Property,  the  Appurtenances  or the  Appurtenant
     Improvements  to which 77 WWLP,  or its agents or affiliates is a party and
     which  would be binding on either or both of the LLC or the  Property,  the
     Appurtenances or the Appurtenant  Improvements  after Closing.  77 WWLP has
     delivered  to OTR or made  available  to OTR  for  inspection  all  written
     materials in the possession or control of 77 WWLP which contain information
     or disclose facts or conditions  that would have a material  adverse impact
     on the use,  operation or marketability of the Property,  the Appurtenances
     or  the  Appurtenant  Improvements.  Copies  of  Property  Information  and
     Supplemental  Property Information delivered to OTR pursuant to Section 3.2
     hereof are or will be true,  correct and  complete  copies.  77 WWLP has no
     Knowledge  of  any  material   inaccuracy   or  omission  in  the  Property
     Information or Supplemental  Property Information delivered as contemplated
     in Section  3.2 or in that  certain  Memorandum  dated  August 5, 1999 from
     Scott McKibben to Stephen Huber attached to Appendix 6.1(e).

          (i) Intentionally deleted.

          (j)  DISTRIBUTIONS  AND DISCLOSURES.  To the Knowledge of Prime and 77
     WWLP,  all  obligations,   disclosures,   consents  and   distributions  in
     connection with the contribution of the Property,  the Appurtenances or the
     Appurtenant Improvements that under applicable law or any applicable, valid
     and  binding  agreements  are  required to be  performed,  given or made or
     received  with respect to any person or entity that  directly or indirectly
     holds an  interest  in 77 WWLP shall be,  and at  Closing  shall have been,
     performed, given and made.

          (k) Intentionally deleted.

          (l) Intentionally deleted.

          (m) Intentionally deleted.

          (n) Intentionally deleted.

          (o)  LITIGATION.  To the Knowledge of 77 WWLP,  except as set forth in
     Appendix  7.1(o)  attached hereto and  incorporated  herein,  no pending or
     threatened (in writing)  litigation or governmental  proceeding  affects 77
     WWLP or the Property, the Appurtenances or the Appurtenant Improvements.

          (p) Intentionally deleted.

          (q) GOVERNMENTAL  ACTIONS. 77 WWLP has not received any written notice
     that any rent controls or  governmental  moratoria  affecting the Property,
     the Appurtenances or the Appurtenant  Improvements are threatened,  pending
     or proposed.



                                      -30-
<PAGE>
          (r) BANKRUPTCY  MATTERS.  To the Knowledge of 77 WWLP, no tenant under
     any Lease of more than 10,000  square feet of net rentable  area has made a
     general  assignment  for the  benefit  of  creditors,  filed any  voluntary
     petition in bankruptcy or suffered the filing of an involuntary petition by
     its creditors, suffered the appointment of a receiver to take possession of
     substantially all of its assets,  suffered the attachment or other judicial
     seizure of substantially  all of its assets,  admitted its inability to pay
     its debts as they come due, or made an offer of  settlement,  extension  or
     composition to its creditors generally.

          (s) Intentionally deleted.

          (t) Intentionally deleted.

          (u) INSURANCE. 77 WWLP carries insurance with respect to the Property,
     the Appurtenances or the Appurtenant Improvements required to be carried by
     the owner of the Property.  All such insurance is in full force and effect.
     To the  Knowledge  of 77 WWLP,  the  Property,  the  Appurtenances  and the
     Appurtenant  Improvements  materially  comply with all requirements of each
     such  policy,  and 77  WWLP  has  not  received  from  any of the  insurers
     thereunder  any  written  notice  requiring  work or  suggesting  that  any
     material  work be  performed  at the  Property,  the  Appurtenances  or the
     Appurtenant Improvements. To the Knowledge of 77 WWLP, there are no defects
     or  inadequacies  in the Property,  the  Appurtenances  or the  Appurtenant
     Improvements  that would adversely  affect the  insurability of the same or
     cause the  imposition of  extraordinary  premiums  therefor or create or be
     likely  to  create  a  hazard,  excessive  maintenance  costs  or  material
     operating deficiencies,  except as disclosed in the Property Information or
     the Supplemental Property Information.

          (v)  KNOWLEDGE.  James  Runnion  has been the person  responsible  for
     managing the Property,  the Appurtenances and the Appurtenant  Improvements
     for 77 WWLP since the completion of the  Improvements  and the  Appurtenant
     Improvements.

          (w) EMPLOYEES. 77 WWLP has no employees.

          (x) PERSONAL  PROPERTY.  The Personal  Property  includes the personal
     property  necessary  to operate the  Property,  the  Appurtenances  and the
     Appurtenant Improvements in the manner currently operated.

     Section 7.2 OTR'S REPRESENTATIONS AND WARRANTIES.  As a material inducement
to 77 WWLP to execute  this  Agreement  and  consummate  this  transaction,  OTR
represents and warrants to 77 WWLP that:

          (a)  ORGANIZATION  AND  AUTHORITY.  OTR has been duly organized and is
     validly  existing  as an  Ohio  partnership.  OTR has the  full  right  and
     authority and has obtained any and all consents required to enter into this
     Agreement  and to consummate or cause to be  consummated  the  transactions
     contemplated  hereby.  This Agreement has been, and all of the documents to
     be  delivered  by OTR at the  Closing  will  be,  authorized  and  properly
     executed and constitute, or will constitute, as appropriate,  the valid and
     binding obligation of OTR, enforceable in accordance with their terms.

          (b) CONFLICTS AND PENDING ACTION. No agreement to which OTR is a party
     or  which  to  OTR's  Knowledge  is  binding  on OTR  conflicts  with  this
     Agreement.  No action or  proceeding  is  pending  or, to OTR's  Knowledge,
     threatened against OTR which challenges or impairs OTR's ability to execute
     or perform its obligations under this Agreement.

     Section 7.3 SURVIVAL OF REPRESENTATIONS AND WARRANTIES. The representations
and  warranties  set  forth  in this  Article  7 are made as of the date of this
Agreement  and are remade as of the  Closing  Date and shall not be deemed to be
merged  into or waived by the  instruments  of  Closing,  but shall  survive the
Closing except as otherwise specifically provided in this Agreement.  Subject to
the terms and provisions of Section 10.19 hereof, the representations in Section


                                      -31-
<PAGE>
7.1(a)  through (f) and (h),  and  Section  7.2 shall  survive the Closing for a
period of  eighteen  (18)  months,  unless a suit is filed  within  such  period
alleging the inaccuracy of such  representations  or warranties,  in which event
such  representations and warranties alleged in such suit to be inaccurate shall
survive until the final resolution of such suit. The  representations in Section
7.1(g) shall survive the Closing for a period of seven (7) years,  unless a suit
is filed within such period alleging the inaccuracy of such  representations  or
warranties,  in which case such  representations  and  warranties  shall survive
until the final resolution of such suit.

                                  ARTICLE VIII

                              DEFAULT AND REMEDIES

     Section 8.1  DEFAULT BY 77 WWLP.  If this  transaction  fails to close as a
result of default by 77 WWLP in the performance of its obligations  hereunder or
any  representation  or warranty of 77 WWLP is inaccurate (all conditions to the
obligations of 77 WWLP having been satisfied or waived)  (herein,  a "default"),
the Escrow  Agent shall  return the Deposit to OTR.  In  addition,  OTR shall be
entitled to the remedy of specific performance. OTR shall not be entitled to any
other  remedy  if this  transaction  fails to close  as a  result  of 77  WWLP's
default.

     Section 8.2 OTR's DEFAULT.  If this transaction  fails to close as a result
of the failure of OTR to perform its obligations hereunder or any representation
or warranty of OTR is inaccurate  (herein a "default")  (all conditions to OTR's
obligations having been satisfied or waived),  then the sole remedies of 77 WWLP
in such event shall be (i) to terminate  this Agreement or (ii) to the remedy of
specific performance.  77 WWLP shall not be entitled to any other remedy if this
transaction fails to close as a result of OTR's default.

     Section 8.3 OTHER  EXPENSES.  If this  Agreement is  terminated  due to the
default  of a party,  then the  defaulting  party  shall pay any fees due to the
Escrow  Agent for holding the Deposit and any fees due to the Title  Company for
cancellation of the Title Commitment, and the Deposit shall be paid to OTR.

                                   ARTICLE IX

                                 INDEMNIFICATION

     Section 9.1 INDEMNITY OF 77 WWLP. 77 WWLP shall indemnify,  defend and hold
the LLC and OTR harmless from any liability,  claim,  demand,  loss,  expense or
damage  (collectively,  "loss")  that is:  suffered by, or asserted by any third
party  against the LLC or OTR arising  from any act or omission of 77 WWLP,  its
respective  agents,  employees or  contractors  or otherwise  arising out of the
ownership or operation of the Property,  the  Appurtenances  and the Appurtenant
Improvements  arising or  occurring  prior to the  Closing,  except that the LLC
shall not be entitled to indemnification with respect to matters as to which the
LLC is specifically  obliged pursuant to this Agreement,  any document delivered
at Closing, or under Section 9.2 to indemnify 77 WWLP.

     Section 9.2 LLC'S INDEMNITY.  77 WWLP and OTR shall take all necessary acts
as members of the LLC to  authorize  and  empower the LLC to agree to, and shall
direct the LLC to  indemnify,  defend and hold 77 WWLP  harmless of and from any
loss that is:  suffered  by, or  asserted by any third  party  against,  77 WWLP
arising  from  any  act or  omission  of  the  LLC,  its  agents,  employees  or
contractors  or  otherwise  arising out of the  ownership  or  operation  of the
Property,  the Appurtenances and the Appurtenant  Improvements  first arising or
occurring  on or after  Closing,  except  that 77 WWLP shall not be  entitled to
indemnification  with  respect to matters as to which 77 WWLP in its  individual
capacity is  specifically  obliged  pursuant  to this  Agreement,  any  document



                                      -32-
<PAGE>
delivered at Closing or under Section 9.1 to indemnify the LLC or OTR and except
that the LLC shall have no liability to indemnify 77 WWLP in connection with the
obligations  of Lessor under Section 29 of the Lease to Jones Day Reavis & Pogue
LLP.

     Section 9.3  PROCEDURE.  The  following  provisions  govern all actions for
indemnity  under  this  Article 9 and any  other  provision  of this  Agreement.
Promptly after receipt by an indemnitee of notice of any claim,  such indemnitee
will,  if a claim in  respect  thereof  is to be made  against  the  indemnitor,
deliver to the indemnitor  written notice thereof and the indemnitor  shall have
the right to  participate  in and, if the  indemnitor  agrees in writing that it
will be responsible  for any costs,  expenses,  judgments,  damages,  and losses
incurred by the  indemnitee  with  respect to such claim,  to assume the defense
thereof,  with counsel mutually satisfactory to the parties. An indemnitee shall
have the right to retain its own counsel,  with the fees and expenses to be paid
by the indemnitee,  if the indemnitee reasonably believes that representation of
such indemnitee by the counsel retained by the indemnitor would be inappropriate
due to actual or potential  differing  interests between such indemnitee and any
other  party  represented  by such  counsel in such  proceeding.  The failure of
indemnitee to deliver written notice to the indemnitor  within a reasonable time
after indemnitee receives notice of any such claim shall relieve such indemnitor
of any  liability  to the  indemnitee  under this  indemnity  only if and to the
extent that such failure is  prejudicial to the  indemnitor's  ability to defend
such action,  and the omission so to deliver  written  notice to the  indemnitor
will not relieve it of any liability  that it may have to any  indemnitee  other
than under this  indemnity.  If an indemnitee  settles a claim without the prior
written  consent of the indemnitor,  then the indemnitor  shall be released from
liability  with respect to such claim  unless the  indemnitor  has  unreasonably
withheld such consent.

     Section  9.4  SURVIVABILITY.  The  obligations  of the  parties  under this
Article 9 shall survive the Closing.

                                    ARTICLE X

                                  MISCELLANEOUS

     Section 10.1 PARTIES BOUND. No party may assign this Agreement  without the
prior written consent of the other, and any such prohibited  assignment shall be
void,   except  that  concurrent  with  Closing,   77  WWLP  may  assign  to  an
"intermediary,"  as such term is contemplated  under  regulations  issued by the
Service to implement  Section 1031 of the Code,  any right of 77 WWLP under this
Agreement to payment that 77 WWLP may deem  necessary so that 77 WWLP may try to
take  advantage of Section 1031 of the Code in  connection  with the transfer of
the Property to the LLC.  Neither OTR nor the LLC shall have any liability to 77
WWLP in any way  connected  with the  attempt  by 77 WWLP to take  advantage  of
Section 1031 of the Code in connection  with the transfer of the  Property,  the
Appurtenances or the Appurtenant Improvements.  OTR shall cooperate with 77 WWLP
in effecting such  exchange.  OTR shall not be obliged to incur any liability or
expense in order to perform such  cooperation  obligation.  Except as limited by
the foregoing,  this Agreement shall be binding upon and inure to the benefit of
the respective successors and assigns of the parties.

     Section 10.2 HEADINGS. The article and paragraph headings of this Agreement
are for convenience  only and in no way limit or enlarge the scope or meaning of
the language hereof.

     Section 10.3  INVALIDITY;  NO WAIVER.  If any portion of this  Agreement is
held  invalid or  inoperative,  then so far as is  reasonable  and  possible the
remainder of this  Agreement  shall be deemed valid and  operative,  and, to the
greatest extent legally possible, effect shall be given to the intent manifested
by the portion  held  invalid or  inoperative.  The  failure by either  party to


                                      -33-
<PAGE>
enforce  against the other any term or provision of this Agreement  shall not be
deemed to be a waiver of such party's  right to enforce  against the other party
the same or any other such term or provision in the future.

     Section 10.4  GOVERNING  LAW. This  Agreement  shall,  in all respects,  be
governed,  construed,  applied,  and enforced in accordance  with the law of the
state of Illinois.

     Section 10.5 SURVIVAL.  The  provisions of this Agreement that  contemplate
performance  after  the  Closing,  the  obligations  of the  parties  not  fully
performed at the Closing and not expressly  waived in writing in connection with
the Closing or  specifically  deemed to have been waived in accordance with this
Agreement,  and all  indemnities  set forth in this Agreement  shall survive the
Closing and shall not be deemed to be merged  into or waived by the  instruments
delivered at Closing.

     Section 10.6 NO THIRD PARTY BENEFICIARY.  This Agreement is not intended to
give or confer any benefits, rights, privileges, claims, actions, or remedies to
any  person  or  entity  (other  than  the  LLC) as a third  party  beneficiary,
designee, or otherwise.

     Section 10.7 ENTIRETY AND  AMENDMENTS.  This Agreement  embodies the entire
agreement   between  the  parties  and  supersedes  all  prior   agreements  and
understandings  relating  to the  Property.  This  Agreement  may be  amended or
supplemented only by an instrument in writing executed by the party against whom
enforcement is sought.

     Section  10.8  TIME.  Time is of the  essence  in the  performance  of this
Agreement.

     Section 10.9  CONFIDENTIALITY.  No party shall make or authorize the LLC to
make any  public  announcement  or other  disclosure  of this  Agreement  or any
information  related  to this  Agreement  to outside  brokers or third  parties,
before or after the Closing,  without the prior written  specific consent of all
the  parties,  except  that a  party  or the  LLC may  make  disclosure  of this
Agreement to its lenders, creditors, officers, employees and agents as necessary
to perform its  obligations  hereunder or to the extent  required by  applicable
Laws.

     Notwithstanding  the foregoing,  this  confidentiality  provision shall not
apply to information:  (a) that is as of the date of this Agreement or hereafter
enters the public domain (other than in violation of this  Agreement),  (b) that
is compelled to be disclosed by law or a court or other binding  order,  and (c)
any  information  required to be disclosed  to any  governmental  bodies  and/or
regulatory agencies,  including, without limitation, the Securities and Exchange
Commission.  Further,  Prime,  77 WWLP and OTR shall  each have the right to (i)
disclose the  existence  of this  Agreement  and the contents  hereof to (1) its
partners, advisers,  underwriters,  analysts, employees,  affiliates,  officers,
directors,  consultants,  potential lenders, tenants and investors,  counsel and
accountants  (and the employees  and agents of such  parties)  provided that the
disclosing  party  advises  such  persons  of the  confidential  nature  of this
Agreement and the transaction  contemplated  hereby,  and (2) analysts  covering
OTR, Prime, 77 WWLP (or its partners), as applicable,  or the REIT industry, and
(ii) file any applicable forms with the Securities and Exchange  Commission that
accurately reflect such factual  information  pertaining to the Property and the
transaction  contemplated  hereby that 77 WWLP  determines  to be  necessary  or
prudent in complying with 77 WWLP's legal disclosure obligations.

     Section 10.10 ATTORNEYS' FEES. Should any party employ attorneys to enforce
any of the  provisions  hereof,  the party  against  whom any final  judgment is
entered  shall pay the  prevailing  party all  reasonable  costs,  charges,  and
expenses,   including  attorneys'  fees  and  costs,  expended  or  incurred  in
connection therewith.

                                      -34-
<PAGE>
     Section 10.11 NOTICES. All notices required or permitted hereunder shall be
in  writing  and shall be served on the  parties at the  addresses  set forth in
Appendix 10.11. Any such notices shall be either (a) sent by overnight  delivery
using a nationally  recognized  overnight courier, in which case notice shall be
deemed  delivered one business day after deposit with such courier,  or (b) sent
by  personal  delivery,  in which case  notice  shall be deemed  delivered  upon
receipt or  refusal  to accept  delivery.  A party's  address  may be changed by
written notice to the other party,  except that no notice of a change of address
shall be effective  until actual  receipt of such notice.  Copies of notices are
for informational  purposes only, and a failure to give or receive copies of any
notice shall not be deemed a failure to give notice. Notices given by counsel to
OTR shall be deemed  given by OTR and  notices  given by  counsel to the 77 WWLP
shall be deemed given by 77 WWLP.

     Section 10.12  CONSTRUCTION.  The parties  acknowledge that the parties and
their counsel have  reviewed and revised this  Agreement and the documents to be
executed at the Closing  and agree that the normal rule of  construction  to the
effect that any ambiguities are to be resolved  against the drafting party shall
not be employed in the  interpretation  of this  Agreement,  the documents to be
delivered at Closing or any exhibits or amendments thereto.

     Section 10.13 CALCULATION OF TIME PERIODS.  Unless otherwise specified,  in
computing any period of time described herein, the day of the act or event after
which the designated  period of time begins to run is not to be included and the
last day of the period so computed is to be included at, unless such last day is
a Saturday,  Sunday or legal  holiday for national  banks in Illinois,  in which
event the  period  shall  run  until the end of the next day which is  neither a
Saturday, Sunday, or legal holiday. The last day of any period of time described
herein shall be deemed to end at 5 p.m. E.D.T.

     Section  10.14  INFORMATION  AND AUDIT  COOPERATION.  At OTR's or the LLC's
request,  at any time before or within two years following the Closing,  77 WWLP
shall provide to any independent  auditor designated by OTR or the LLC access to
the books and records of the Property.

     Section 10.15 EXECUTION IN COUNTERPARTS.  This Agreement may be executed in
any number of counterparts, each of which shall be deemed to be an original. All
of such counterparts shall constitute one Agreement.  To facilitate execution of
this  Agreement,  the parties may execute and  exchange by  telephone  facsimile
counterparts of the signature pages.

     Section  10.16  EXCULPATION.  (a) This  Agreement  is  executed  by certain
general partners of OTR, not  individually,  but solely on behalf of, and as the
authorized  nominee and agent for The State  Teachers  Retirement  Board of Ohio
("STRBO"), and in consideration for entering into this Agreement, 77 WWLP hereby
waives any rights to bring a cause of action against the  individuals  executing
this  Agreement on behalf of OTR (except for any cause of action based upon lack
of  authority  or fraud),  and all persons  dealing with OTR must look solely to
STRBO's assets for the enforcement of any claim against OTR, and the obligations
hereunder are not binding upon, nor shall resort be had to the private  property
of any of, the trustees, officers, directors, employees or agents of STRBO.

          (b)  This   Agreement   is  executed  by  certain   individuals,   not
     individually, but solely on behalf of, and as the authorized representative
     for 77 WWLP and its general partners. OTR hereby waives any rights to bring
     a cause of action  against the  individuals  executing  this  Agreement  on
     behalf  of 77 WWLP  (except  for any  cause of  action  based  upon lack of
     authority or fraud),  and all persons dealing with 77 WWLP must look solely
     to the assets of 77 WWLP and its general partner and such general partner's
     general  partner for the  enforcement of any claim against 77 WWLP, and the
     obligations  hereunder are not binding upon, nor shall resort be had to the
     private property of any of the trustees, officers, directors,  employees or


                                      -35-
<PAGE>
     agents  of (i) 77 WWLP  or  (ii)  the  general  partner  of 77 WWLP or such
     general partner's general partners.

     Section 10.17 FURTHER ASSURANCES. In addition to the acts and deeds recited
herein and contemplated to be performed, executed and/or delivered by each party
at Closing,  each party shall  perform,  execute  and  deliver,  but without any
obligation to incur any additional liability or expense, on or after the Closing
any  further  deliveries  and  assurances  as may  be  reasonably  necessary  to
consummate  the  transactions  contemplated  hereby or to  further  perfect  the
conveyance, transfer and assignment of the Property to the LLC.

     Section 10.18 BULK SALES. If any applicable  provisions of law require that
any  state  or  local  taxation  authorities  be  notified  of the  transactions
contemplated  herein, or if clearance is required of such  authorities,  each in
order  to  permit  the  transfer  of the  Property,  the  Appurtenances  and the
Appurtenant Improvements as contemplated herein without liability to 77 WWLP for
any state or local taxes  required to be paid or  collected  by 77 WWLP prior to
the Closing  Date, a condition  precedent to the  obligations  of OTR  hereunder
shall be that all such notification and clearance  requirements  shall have been
complied with and OTR and the LLC shall have  received the requisite  clearances
and  releases  from further  liability or the amount  included on any bulk sales
form shall have been  withheld  from amounts  payable to 77 WWLP. 77 WWLP shall,
within ten (10) days after the date hereof, make all filings necessary to obtain
such clearances and shall contemporaneously  provide OTR with copies of all such
filings.

     Section 10.19  NOTIFICATION OF CERTAIN  MATTERS.  77 WWLP shall give prompt
notice to OTR upon  becoming  aware of, and OTR shall give  prompt  notice to 77
WWLP upon becoming aware of, (a) the occurrence or  non-occurrence  of any event
the  occurrence or  non-occurrence  of which would cause any  representation  or
warranty  contained in this Agreement to be untrue or inaccurate in any material
respect at or prior to the Closing Date and (b) any material  failure of 77 WWLP
or OTR, as the case may be, to comply with or satisfy any covenant, condition or
agreement to be complied with or satisfied by it hereunder.  The delivery of any
notice  pursuant to this Section  10.19 shall not limit or otherwise  affect the
remedies available hereunder to the party receiving such notice.

     If OTR becomes aware of the occurrence or  non-occurrence of any event, the
occurrence or non-occurrence of which would cause any representation or warranty
contained in this  Agreement to be untrue or inaccurate in any material  respect
at or prior to the Closing,  OTR shall immediately  notify 77 WWLP of such event
or information,  and if OTR nonetheless performs its obligations under Article 5
of this  Agreement  and acquires a membership  interest in the LLC, OTR shall be
deemed to have waived all claims  resulting from any such untruth or inaccuracy,
and 77 WWLP  shall  not be  liable  to OTR for  damages  as a result of any such
untruth or  inaccuracy.  77 WWLP  shall have the burden of proving  that OTR was
aware on or before  Closing  of the  occurrence  or  non-occurrence  of any such
event.

     Section 10.20  TERMINATION.  This Agreement may be terminated and abandoned
at any time prior to the Closing:

          (a) By the mutual written consent of 77 WWLP and OTR; and

          (b)  In  the  circumstances  otherwise  specified  elsewhere  in  this
     Agreement.

     Section  10.21  PROCEDURE  AND EFFECT OF  TERMINATION.  In the event of the
termination  and  abandonment  of this Agreement  contemplated  in Section 10.20
hereof:

          (a) Each party will  redeliver  all  documents,  work papers and other
     material  of any other  party  relating  to the  transactions  contemplated

                                      -36-
<PAGE>
     hereby,  whether so obtained before or after the execution  hereof,  to the
     party furnishing the same;

          (b) All  confidential  information  received by any party  hereto with
     respect to the  business  of any other party or its  subsidiaries  shall be
     held in confidence as provided in Section 10.9; and

          (c) the Deposit shall be returned to OTR.

     Section 10.22 REMEDIES  CUMULATIVE;  EQUITABLE RELIEF.  Except as otherwise
provided  in  Article  VIII and  elsewhere  in this  Agreement,  all  rights and
remedies which any party may be entitled to exercise under this Agreement may be
exercised cumulatively,  successively, and without prejudice to any other rights
and remedies to which such party may be entitled,  at law or in equity.  Without
limitation of the foregoing, the parties hereto agree that irreparable damage to
OTR and 77 WWLP would occur in the event that the  provisions of this  Agreement
were not performed in accordance  with their  specific  terms or were  otherwise
breached.  Accordingly,  both OTR and 77 WWLP shall be entitled to an injunction
or injunctions to prevent breaches of this Agreement and to enforce specifically
the terms and  provisions  hereof in any court of the United States or any state
having jurisdiction,  this being in addition to any other remedy to which OTR or
77 WWLP is entitled at law or in equity.

     Section  10.23  WAIVER  OF  COMPLIANCE;   CONSENTS.   Except  as  otherwise
specifically  provided in this  Agreement,  any failure of Prime and 77 WWLP, on
the one  hand,  or OTR,  on the  other  hand,  to  comply  with any  obligation,
covenant,  agreement  or  condition  herein  may be  waived  by OTR or 77  WWLP,
respectively,  only by a written  instrument  signed by the party  granting such
waiver,  but such waiver or failure to insist upon strict  compliance  with such
obligation,  covenant,  agreement or condition shall not operate as a waiver of,
or estoppel  with respect to, any  subsequent  or other  failure.  Whenever this
Agreement requires or permits consent by or on behalf of any party hereof,  such
consent shall be given in writing in a manner  consistent with the  requirements
for a waiver of compliance as set forth in this Section 10.23.

     Section 10.24 Intentionally deleted.

     Section 10.25 WAIVER OF JURY TRIAL.  TO THE EXTENT  PERMITTED BY APPLICABLE
LAW, THE PARTIES HEREBY  IRREVOCABLY WAIVE ANY AND ALL RIGHT TO TRIAL BY JURY IN
ANY LEGAL  PROCEEDING  ARISING  OUT OF OR  RELATING  TO THIS  AGREEMENT,  OR THE
TRANSACTIONS CONTEMPLATED HEREBY.

     Section 10.26 LIKE KIND EXCHANGE.

          (a) OTR agrees to  cooperate  with Prime and 77 WWLP,  as described in
     subsection  (b) below,  to  accommodate  the desire of 77 WWLP to treat the
     transfer  of  the  Property,   the   Appurtenances   and  the   Appurtenant
     Improvements and distribution to 77 WWLP  contemplated by this Agreement as
     part of a tax deferred  exchange by 77 WWLP under Section 1031 of the Code;
     however,  OTR and 77 WWLP  acknowledge  and agree  that OTR  shall  have no
     responsibility for the tax treatment to 77 WWLP or Prime.

          (b) In order to  accommodate  77 WWLP,  OTR agrees that (i) consistent
     with Section 10.26(a) hereof,  it shall make payment of, as requested by 77
     WWLP, to the person or persons  designated by 77 WWLP, which person will be
     intended to be a "qualified  escrow" or  "qualified  trust" for purposes of
     Section 1.031(k)-1(g)(3) of the Treasury Regulations, and (ii) as requested
     by 77 WWLP,  OTR will  consent to the  assignment  of this  Agreement on or
     after the date  hereof  to a person,  who is  intended  to be a  "qualified
     intermediary"  for  purposes of Section  1.1031(k)-1(g)(3)  of the Treasury
     Regulations.  Notwithstanding such assignment, 77 WWLP shall remain jointly
     and  severally  liable  for  performance  of  the  obligations  of 77  WWLP
     hereunder  and for  the  representations  and  warranties  of 77 WWLP  made
     hereunder.
                                      -37-
<PAGE>
     Section 10.27  SPRINKLER  HEADS. 77 WWLP shall obtain on or before December
31, 1999 a letter from a testing laboratory  reasonably  satisfactory to OTR and
recognized by Underwriter's Laboratories to the effect that such laboratory does
not  recommend  that  any  further  action  (other  than  ordinary   repair  and
maintenance)  is  necessary  to address  issues  raised by the type of sprinkler
heads currently installed in the fire suppression system in the Improvements and
the Additional Improvements.  If 77 WWLP is unable to obtain such letter by such
date, 77 WWLP at its sole cost and expense shall  replace such  sprinkler  heads
with sprinkler  heads as to which 77 WWLP receives a letter as  contemplated  in
the  previous  sentence as soon as  reasonably  possible  and in any event on or
before  September 30, 2000. The  obligations of 77 WWLP under this section 10.27
shall survive Closing.

     OTR  acknowledges  and agrees that 77 WWLP may pursue claims and recoveries
at its expense  relating  to the  sprinkler  heads.  Any such  recovery  that it
receives shall be the sole property of 77 WWLP, and not that of the LLC or OTR.

     Section 10.28  HOLIDAYS.  Whenever  under the terms and  provisions of this
Agreement  the time for  performance  falls  upon a  Saturday,  Sunday  or legal
holiday, such time for performance shall be extended to the next business day.

                             77 WEST WACKER LIMITED PARTNERSHIP

                             By Prime Group Realty, L.P., a limited partnership
                             organized under the laws of Delaware, its general
                             partner

                             By Prime Group Realty Trust, a real estate
                             investment trust organized under the laws of
                             Maryland, its managing general partner


                             By: /s/ Jeffrey A. Patterson
                                ------------------------------------------------

                             Name:   Jeffrey A. Patterson
                                   ---------------------------------------------

                             Title:  Executive Vice President
                                   ---------------------------------------------

                             OTR


                             By: /s/ Stephen A. Mitchell
                                ------------------------------------------------
                                     Stephen A. Mitchell, general partner
                                ------------------------
















                                      -38-
<PAGE>
                                    EXHIBIT A
                                    ---------

             LEASING COMMISSIONS AFTER CLOSING - OBLIGATIONS OF LLC
             ------------------------------------------------------


The LLC shall pay the following leasing commission:

- ---------------------------  ---------  ----------------  ---------------------
           Tenant               RSF     Leasing Comm/RSF   Leasing Commissions
- ---------------------------  ---------  ----------------  ---------------------
A.  Zevnich & Horton           22,067       $  2.85            $   62,891

B.  McGuire Woods Bottle       22,617       $  8.55            $  193,375
    & Boothe LLP Expansion

                             ---------                         ------------
                  Total        44,684                          $  256,266

The LLC pays all  commissions  due and payable to leasing  brokers in connection
with extension  and/or renewal of Leases  following the Closing Date,  except as
provided in Appendix 6.1(e) to the contrary.









































                                      -39-
<PAGE>
                                   EXHIBIT B-1
                                   -----------

                        PROPERTY SUBJECT TO APPURTENANCES
                        ---------------------------------

TO THE  EXTENT OF ANY  INCONSISTENCY  BETWEEN  THE LEGAL  DESCRIPTIONS  SHOWN IN
APPENDIX  2.7(2) AND THIS EXHIBIT B-1, THAT SHOWN IN THE APPENDIX SHALL CONTROL.
THE LEASEHOLD ESTATE CREATED BY THE INSTRUMENT  HEREIN REFERRED TO AS THE LEASE,
EXECUTED BY:  AMERICAN  NATIONAL BANK AND TRUST  COMPANY OF CHICAGO,  AS TRUSTEE
UNDER TRUST  AGREEMENT  DATED NOVEMBER 26, 1985 AND KNOWN AS TRUST NUMBER 66121,
AS  LESSOR,  AND  77  WEST  WACKER  LIMITED  PARTNERSHIP,  AN  ILLINOIS  LIMITED
PARTNERSHIP AS LESSEE,  DATED MARCH 7, 1991,  WHICH LEASE WAS RECORDED MARCH 18,
1991 AS  DOCUMENT  91119739  WHICH  DEMISED  PARCEL 7 FOR A TERM OF YEARS AS SET
FORTH  THEREIN,  AND DEMISES THE  "APPURTENANT  RIGHTS" SET FORTH IN PARCEL B OF
EXHIBIT  'B' TO SAID LEASE OVER PARCEL 10 FOR SAID TERM,  SAID  PARCELS 7 AND 10
BEING DESCRIBED AS FOLLOWS:

PARCEL 7:

THE  PROPERTY AND SPACE WHICH LIES  BETWEEN  HORIZONTAL  PLANES WHICH ARE +50.63
FEET AND +80.63 FEET,  RESPECTIVELY  ABOVE THE CHICAGO CITY DATUM,  AND WHICH IS
ENCLOSED BY VERTICAL PLANES EXTENDING UPWARD FROM THE BOUNDARIES, AT THE SURFACE
OF THE EARTH,  OF THAT PART OF BLOCK 17 IN THE ORIGINAL TOWN OF CHICAGO,  IN THE
SOUTHEAST  1/4 OF  SECTION 9,  TOWNSHIP  39 NORTH,  RANGE 14,  EAST OF THE THIRD
PRINCIPAL MERIDIAN, BOUNDED AND DESCRIBED AS FOLLOWS:

ALL OF  SUB-LOTS  1 TO 7 AND THE ALLEY IN THE  ASSESSOR'S  DIVISION  OF LOT 5 IN
BLOCK 17 IN THE  ORIGINAL  TOWN OF CHICAGO;  ALSO,  LOT 6 (EXCEPT THE EAST 20.00
FEET  THEREOF) IN BLOCK 17 IN THE ORIGINAL  TOWN OF CHICAGO ALL IN THE SOUTHEAST
1/4 OF SECTION  9,  TOWNSHIP  39 NORTH,  RANGE 14,  EAST OF THE THIRD  PRINCIPAL
MERIDIAN, IN COOK COUNTY, ILLINOIS.

PARCEL 10:

THAT PART OF THE LAND DESCRIBED BELOW WHICH IS DEMISED AS APPURTENANT  RIGHTS IN
THE LEASE NOTED ABOVE:

THAT PART OF THE LAND DESCRIBED BELOW WHICH IS DEMISED AS APPURTENANT  RIGHTS IN
THE LEASE NOTED ABOVE:

THAT PART OF BLOCK 17 IN THE ORIGINAL  TOWN OF CHICAGO IN THE  SOUTHEAST  1/4 OF
SECTION 9,  TOWNSHIP 39 NORTH,  RANGE 14 EAST OF THE THIRD  PRINCIPAL  MERIDIAN,
BOUNDED AND DESCRIBED AS FOLLOWS:

ALL OF  SUB-LOTS 1 TO 7, AND THE ALLEY IN THE  ASSESSOR'S  DIVISION  OF LOT 5 IN
BLOCK 17 IN THE ORIGINAL TOWN OF CHICAGO; ALSO LOT 6 (EXCEPT THE EAST 20.00 FEET
THEREOF) IN BLOCK 17 IN THE ORIGINAL  TOWN OF CHICAGO;  ALL IN THE SOUTHEAST 1/4
OF SECTION 9, TOWNSHIP 39 NORTH, RANGE 14, EAST OF THE THIRD PRINCIPAL MERIDIAN,
EXCEPT THAT PART WHICH LIES BETWEEN HORIZONTAL PLANES,  WHICH ARE 50.63 FEET AND
80.63 FEET, RESPECTIVELY, ABOVE CHICAGO DATUM.

I.  RIGHT TO PART 169 CARS ON THOSE  PORTIONS  OF  PARCEL  11B,  AS SET FORTH IN
PARKING AGREEMENT DATED OCTOBER 22, 1991 AND RECORDED APRIL 17, 1992 AS DOCUMENT
92280477  AMONG  AMERICAN  NATIONAL BANK AND TRUST COMPANY OF CHICAGO AS TRUSTEE
UNDER TRUST  AGREEMENT  DATED JUNE 18, 1991 AND KNOWN AS TRUST NUMBER 52947,  77
WEST WACKER LIMITED PARTNERSHIP,  AND OTHERS, SAID PARCEL 11 BEING DESCRIBED, AS
FOLLOWS:

PARCEL 11:

11A.  ALL OF  SUBLOTS 1 TO 7 AND THE ALLEY IN  ASSESSOR'S  DIVISION  OF LOT 5 IN
BLOCK 17 IN THE ORIGINAL TOWN OF CHICAGO;

                                      -40-
<PAGE>
ALSO

LOT 6 (EXCEPT THE EAST 20 FEET THEREOF) IN SAID BLOCK 17;

ALSO

ALL OF SUB-LOTS 1 TO 8 IN THE  SUBDIVISION  OF LOT 8 IN SAID BLOCK 17 ALL IN THE
SOUTHEAST  1/4 OF  SECTION 9,  TOWNSHIP  39 NORTH,  RANGE 14,  EAST OF THE THIRD
PRINCIPAL MERIDIAN, IN COOK COUNTY, ILLINOIS.

ALSO

THE NORTH  111.00  FEET OF THE EAST 1/2 OF LOT 7 (AS SUCH  EAST 1/2 IS  MEASURED
ALONG  THE  SOUTH  LINE OF LOT 7),  LYING  ABOVE A  HORIZONTAL  PLANE  HAVING AN
ELEVATION OF +22.00 FEET ABOVE CHICAGO CITY DATUM;

THE SOUTH 16.00 FEET OF THE NORTH  127.00 FEET OF THE EAST 1/2 OF LOT 7 (AS SUCH
EAST 1/2 IS MEASURED  ALONG THE SOUTH LINE OF LOT 7),  LYING ABOVE A  HORIZONTAL
PLANE HAVING AN ELEVATION OF +14.66 FEET ABOVE CHICAGO CITY DATUM;

THAT PART OF THE EAST 1/2 OF LOT 7 (AS SUCH EAST 1/2 IS MEASURED ALONG THE SOUTH
LINE OF LOT 7) EXCEPT THE NORTH  127.00 FEET  THEREOF,  LYING ABOVE A HORIZONTAL
PLANE HAVING AN ELEVATION OF +12.66 FEET ABOVE CHICAGO CITY DATUM;

THE  EAST 20  FEET  OF LOT 6 AND THE  WEST  1/2 OF LOT 7 (AS  SUCH  WEST  1/2 IS
MEASURED  ALONG THE SOUTH LINE OF LOT 7), LYING ABOVE A HORIZONTAL  PLANE HAVING
AN ELEVATION OF +29.00 FEET ABOVE CHICAGO CITY DATUM;

ALL IN BLOCK 17 IN THE ORIGINAL  TOWN OF CHICAGO IN THE SOUTHEAST 1/4 OF SECTION
9,  TOWNSHIP 39 NORTH RANGE 10, EAST OF THE THIRD  PRINCIPAL  MERIDIAN,  IN COOK
COUNTY, ILLINOIS.

11B. LOT 27 IN LOOP  TRANSPORTATION  CENTER  SUBDIVISION  OF PART OF BLOCK 18 IN
ORIGINAL  TOWN OF CHICAGO IN THE  SOUTHEAST 1/4 OF SECTION 9, TOWNSHIP 39 NORTH,
RANGE 14, EAST OF THE THIRD PRINCIPAL MERIDIAN, IN COOK COUNTY, ILLINOIS.





























                                      -41-
<PAGE>
                                   EXHIBIT B-2
                                   -----------

                               Description of Land
                               -------------------

TO THE  EXTENT OF ANY  INCONSISTENCY  BETWEEN  THE LEGAL  DESCRIPTIONS  SHOWN IN
APPENDIX 2.7(2) AND THIS EXHIBIT, THAT SHOWN IN THE APPENDIX SHALL CONTROL.

PARCEL 1:

LOT 3 (EXCEPT THE EAST 20.50 FEET THEREOF); TOGETHER WITH THE NORTH 1.00 FOOT OF
THE ORIGINAL  18-FOOT  ALLEY LYING SOUTH OF AND ADJOINING THE SOUTH LINE OF SAID
LOT 3 IN BLOCK 17 IN THE  ORIGINAL  TOWN OF CHICAGO IN  SECTION 9,  TOWNSHIP  39
NORTH, RANGE 14, EAST OF THE THIRD PRINCIPAL MERIDIAN, IN COOK COUNTY, ILLINOIS.

AND

LOT 1 TO 9, BOTH INCLUSIVE, IN THE SUBDIVISION OF LOT 4; TOGETHER WITH THE NORTH
1.50 FEET OF THE ORIGINAL  18-FOOT  ALLEY LYING SOUTH OF AND ADJOINING THE SOUTH
LINE OF SAID SUBDIVISION OF LOT 4 IN BLOCK 17 IN THE ORIGINAL TOWN OF CHICAGO IN
SECTION 9, TOWNSHIP 39 NORTH, RANGE 14, EAST OF THE THIRD PRINCIPAL MERIDIAN, IN
COOK COUNTY, ILLINOIS.

PARCEL 2:

THAT PART OF THE WEST 1/2 OF NORTH  GARVEY  COURT (SAID NORTH GARVEY COURT BEING
THE WEST 1/2 OF LOT 2 AND THE EAST 20.50 FEET OF LOT 3;  TOGETHER WITH THE NORTH
1.00 FOOT OF THE ORIGINAL  18-FOOT  ALLEY LYING SOUTH OF AND ADJOINING THE SOUTH
LINE OF THE AFORESAID  PARTS OF LOTS 2 AND 3; THE SOUTH OF SAID 1.00 FOOT STRIP,
BEING THE NORTH LINE OF WEST HADDOCK PLACE AS  ESTABLISHED  BY ORDINANCE  PASSED
SEPTEMBER 17, 1852) LYING ABOVE AN INCLINED  PLANE HAVING AN ELEVATION OF +17.26
FEET ABOVE THE CHICAGO CITY DATUM, MEASURED ALONG THE NORTH LINE OF BLOCK 17 AND
HAVING AN ELEVATION OF +21.23 FEET ABOVE THE CHICAGO CITY DATUM,  MEASURED ALONG
THE NORTH LINE OF WEST HADDOCK PLACE ALL IN BLOCK 17, (AS VACATED BY THE CITY OF
CHICAGO IN AN ORDINANCE  PASSED  MARCH 21, 1990 AND  RECORDED  APRIL 11, 1990 AS
DOCUMENT  90164868),  IN THE ORIGINAL  TOWN OF CHICAGO IN SECTION 9, TOWNSHIP 39
NORTH, RANGE 14, EAST OF THE THIRD PRINCIPAL MERIDIAN, IN COOK COUNTY, ILLINOIS.

PARCEL 4:

THAT PART OF WEST HADDOCK PLACE AS ESTABLISHED BY ORDINANCE PASSED SEPTEMBER 17,
1852;  TOGETHER  WITH THE SOUTH 1.50 FEET OF THE  ORIGINAL  18-FOOT  ALLEY LYING
NORTH OF AND ADJOINING THE NORTH LINE OF LOT 1 IN THE ASSESSOR'S DIVISION OF LOT
5 IN BLOCK 17; ALSO,  THE SOUTH 1.00 FOOT OF SAID  ORIGINAL  18-FOOT ALLEY LYING
NORTH OF AND  ADJOINING  THE NORTH  LINE OF LOT 6 IN BLOCK 17,  ALL TAKEN AS ONE
TRACT, LYING WEST OF THE SOUTHERLY  EXTENSION OF THE WEST LINE OF THE EAST 20.50
FEET OF LOT 3 IN SAID  BLOCK 17 AND LYING  EAST OF THE WEST LINE OF BLOCK 17 AND
ITS EXTENSIONS,  (AS VACATED BY THE CITY OF CHICAGO IN AN ORDINANCE PASSED MARCH
21, 1990 AND RECORDED APRIL 11, 1990 AS DOCUMENT  90164868) IN THE ORIGINAL TOWN
OF  CHICAGO  IN  SECTION  9,  TOWNSHIP  39 NORTH,  RANGE  14,  EAST OF THE THIRD
PRINCIPAL MERIDIAN, IN COOK COUNTY, ILLINOIS.

EASEMENT  APPURTENANT  TO AND FOR THE  BENEFIT OF PARCELS 1, 2, AND 4 CREATED BY
THE GRANT OF  EASEMENT  RECORDED  AS  DOCUMENT  90164870  AS AMENDED BY DOCUMENT
91096330 FOR  INGRESS,  EGRESS,  CONSTRUCTION,  USE AND  MAINTENANCE  OF A PLAZA
WALKWAY OVER PARCELS 3 AND 5, SAID PARCELS 3 AND 5 BEING DESCRIBED AS FOLLOWS:

PARCEL 3:

THAT PART OF THE EAST 1/2 OF NORTH  GARVEY  COURT (SAID NORTH GARVEY COURT BEING
THE WEST 1/2 OF LOT 2 AND THE EAST 20.50 FEET OF LOT 3;  TOGETHER WITH THE NORTH
1.00 FOOT OF THE ORIGINAL  18-FOOT  ALLEY LYING SOUTH OF AND ADJOINING THE SOUTH

                                      -42-
<PAGE>
LINE OF THE  AFORESAID  PARTS OF LOTS 2 AND 3, THE SOUTH  LINE OF SAID 1.00 FOOT
STRIP BEING THE NORTH LINE OF WEST  HADDOCK  PLACE AS  ESTABLISHED  BY ORDINANCE
PASSED  SEPTEMBER 17, 1852) LYING ABOVE AN INCLINED PLANE HAVING AN ELEVATION OF
+17.26 FEET ABOVE THE CHICAGO CITY DATUM, MEASURED ALONG THE NORTH LINE OF BLOCK
17 AND HAVING AN ELEVATION OF +21.23 FEET ABOVE THE CHICAGO CITY DATUM, MEASURED
ALONG THE NORTH LINE OF WEST  HADDOCK  PLACE AND LYING BELOW AN  INCLINED  PLANE
HAVING AN ELEVATION OF 47.26 FEET ABOVE CHICAGO CITY DATUM,  MEASURED  ALONG THE
NORTH LINE OF SAID BLOCK 17 AND HAVING AN ELEVATION OF +51.23 FEET ABOVE CHICAGO
CITY DATUM, MEASURED ALONG THE NORTH LINE OF WEST HADDOCK PLACE, ALL IN BLOCK 17
IN THE ORIGINAL TOWN OF CHICAGO, IN SECTION 9, TOWNSHIP 39 NORTH, RANGE 14, EAST
OF THE THIRD PRINCIPAL MERIDIAN, IN COOK COUNTY, ILLINOIS.

PARCEL 5

THAT PART OF WEST HADDOCK PLACE AS ESTABLISHED BY ORDINANCE PASSED SEPTEMBER 17,
1852;  TOGETHER  WITH THE SOUTH 1.00 FOOT OF THE  ORIGINAL  18-FOOT  ALLEY LYING
NORTH OF AND  ADJOINING  THE  NORTH  LINE OF THE WEST 1/2 OF LOT 7 AND THE NORTH
LINE OF THE EAST  20.50  FEET OF LOT 6 ALL TAKEN AS ONE TRACT  LYING EAST OF THE
SOUTHERLY EXTENSION OF THE WEST LINE OF THE EAST 20.50 FEET OF LOT 3 IN BLOCK 17
IN THE ORIGINAL TOWN OF CHICAGO,  LYING WEST OF THE  SOUTHERLY  EXTENSION OF THE
EAST LINE OF THE WEST 1/2 OF LOT 2 IN SAID  BLOCK 17,  LYING  ABOVE AN  INCLINED
PLANE,  HAVING AN  ELEVATION OF +21.23 FEET ABOVE  CHICAGO CITY DATUM,  MEASURED
ALONG THE NORTH LINE OF WEST HADDOCK PLACE AFORESAID, AND HAVING AN ELEVATION OF
+21.72  FEET ABOVE  CHICAGO  CITY  DATUM,  MEASURED  ALONG THE SOUTH LINE OF THE
ORIGINAL 18-FOOT ALLEY AFORESAID,  AND LYING BELOW AND INCLINED PLANE, HAVING AN
ELEVATION OF +71.23 FEET ABOVE CHICAGO CITY DATUM, MEASURED ALONG THE NORTH LINE
OF WEST HADDOCK  PLACE  AFORESAID,  AND HAVING AN ELEVATION OF +71.72 FEET ABOVE
CHICAGO CITY DATUM,  MEASURED ALONG THE SOUTH LINE OF THE ORIGINAL 18-FOOT ALLEY
AFORESAID,  ALL IN SECTION 9,  TOWNSHIP  39 NORTH,  RANGE 14,  EAST OF THE THIRD
PRINCIPAL MERIDIAN, IN COOK COUNTY, ILLINOIS.

EASEMENTS  FOR  SUPPORT AS CREATED BY GRANT OF  EASEMENT  RECORDED  AS  DOCUMENT
90164870  AS AMENDED BY  DOCUMENT  91096330  OVER  PARCEL 6, SAID PARCEL 6 BEING
DESCRIBED AS FOLLOWS:

PARCEL 6:

THAT PART OF GARVEY  COURT  DEPICTED  IN  EXHIBIT  "B" OF THE GRANT OF  EASEMENT
RECORDED AS DOCUMENT 90164870 AS AMENDED BY DOCUMENT 91096330.

RECIPROCAL  EASEMENT  AGREEMENT  DATED DECEMBER 5, 1990 AND RECORDED AS DOCUMENT
91092145 MADE BY AND BETWEEN  CHICAGO TITLE AND TRUST COMPANY,  AS TRUSTEE UNDER
TRUST  AGREEMENT  DATED  NOVEMBER 12, 1986 AND KNOWN AS TRUST NO. 1088617 AND 77
WEST WACKER LIMITED PARTNERSHIP,  AN ILLINOIS LIMITED  PARTNERSHIP,  FOR A JOINT
ACCESS STAIRWAY  CONNECTING THE TWO PARTIES' PROPERTY AS SPECIFICALLY  DESCRIBED
IN SAID INSTRUMENT OVER PARCEL 8, SAID PARCEL 8 BEING DESCRIBED AS FOLLOWS:

PARCEL 8:

THAT PORTION OF THE LAND  DESCRIBED  BELOW (THE  STAIRWAY  LAND)  SUBJECT TO THE
EASEMENT  SET  FORTH  ABOVE:  LOT 1 AND THE EAST 1/2 OF LOT 2 IN BLOCK 17 OF THE
ORIGINAL TOWN OF CHICAGO IN SECTION 9, TOWNSHIP 39 NORTH,  RANGE 14, EAST OF THE
THIRD PRINCIPAL MERIDIAN, IN COOK COUNTY, ILLINOIS.

AND

A STRIP OF LAND LYING SOUTH OF AND  ADJOINING LOT 1 AND THE EAST 1/2 OF LOT 2 IN
BLOCK 17 OF THE ORIGINAL TOWN OF CHICAGO  BOUNDED ON THE NORTH BY THE SOUTH LINE
OF SAID LOTS AND ON THE SOUTH BY THE NORTH LINE OF PUBLIC  ALLEY AS  NARROWED BY
ORDINANCE  OF THE COMMON  COUNCIL OF THE CITY OF CHICAGO  PASSED  SEPTEMBER  17,
1852, ALL IN COOK COUNTY, ILLINOIS.



                                      -43-
<PAGE>
EASEMENTS OVER PARCEL 9 AS SET FORTH IN AGREEMENT BY AND AMONG AMERICAN NATIONAL
BANK AND TRUST  COMPANY OF  CHICAGO,  AS TRUSTEE  UNDER  TRUST  AGREEMENT  DATED
NOVEMBER  26,  1985  AND  KNOWN  AS  TRUST  NUMBER  66121,  200  NORTH  DEARBORN
PARTNERSHIP,  AMERICAN  NATIONAL BANK AND TRUST  COMPANY OF CHICAGO,  AS TRUSTEE
UNDER TRUST AGREEMENT DATED DECEMBER 19, 1989 AND KNOWN AS TRUST NUMBER 11025-08
AND 77 WEST WACKER  LIMITED  PARTNERSHIP,  DATED  DECEMBER 31, 1990 AND RECORDED
MARCH 18, 1991 AS DOCUMENT  91119736,  FOR WALL OPENINGS;  USING,  CONSTRUCTING,
MAINTAINING, REPAIRING, RECONSTRUCTING AND RENEWING THE PLAZA, AND EXTENDING AND
CONTINUING  THE PLAZA;  AND FOR "WALL  WORK" AS THEREIN  DEFINED,  SAID PARCEL 9
BEING DESCRIBED AS FOLLOWS:

PARCEL 9

THAT  PORTION  OF THE LAND  DESCRIBED  BELOW  (THE  WALL  LAND)  SUBJECT  TO THE
EASEMENTS  SET  FORTH  ABOVE:  ALL  OF  SUB-LOTS  1 TO 7 AND  THE  ALLEY  IN THE
ASSESSOR'S  DIVISION OF LOT 5 IN BLOCK 17 IN THE ORIGINAL TOWN OF CHICAGO;  ALSO
LOT 6 (EXCEPT THE EAST 20.00 FEET  THEREOF) IN BLOCK 17 IN THE ORIGINAL  TOWN OF
CHICAGO ALL IN THE SOUTHEAST 1/4 OF SECTION 9, TOWNSHIP 39 NORTH, RANGE 14, EAST
OF THE THIRD PRINCIPAL MERIDIAN, IN COOK COUNTY, ILLINOIS.

SUPPORT AND INGRESS AND EGRESS  EASEMENTS AS CREATED BY AGREEMENT  DATED OCTOBER
22, 1991,  AND RECORDED  MARCH 26, 1992,  AS DOCUMENT  92199746  AMONG  AMERICAN
NATIONAL  BANK AND TRUST COMPANY OF CHICAGO,  AS TRUSTEE  UNDER TRUST  AGREEMENT
DATED JUNE 18,  1991,  AND KNOWN AS TRUST  NUMBER  52947,  AND OTHERS OVER THOSE
PORTIONS OF PARCELS  11A AND 11B,  WHICH ARE SET FORTH IN SAID  AGREEMENT;  SAID
PARCEL 11 BEING DESCRIBED IN EXHIBIT B-1 TO THIS CONTRIBUTION AGREEMENT.

CONSTRUCTION,  REPAIR,  SUPPORT,  AND INGRESS AND EGRESS EASEMENTS AS CREATED BY
AGREEMENT  DATED  OCTOBER 22, 1991,  AND RECORDED  NOVEMBER 12, 1991 AS DOCUMENT
91591893 AMONG AMERICAN  NATIONAL BANK AND TRUST COMPANY OF CHICAGO,  AS TRUSTEE
UNDER TRUST AGREEMENT DATED NOVEMBER 26, 1985,  KNOWN AS TRUST NUMBER 66121M AND
OTHERS OVER THOSE PORTIONS OF PARCEL 11A, WHICH ARE SET FORTH IN SAID AGREEMENT,
SAID PARCEL 11 BEING DESCRIBED IN EXHIBIT B-1 TO THIS CONTRIBUTION AGREEMENT.































                                      -44-
<PAGE>
                                    EXHIBIT C
                                    ---------

                              Management Agreement
                              --------------------

     77 WWLP and OTR shall  negotiate the terms of the Management  Agreement for
fourteen (14) days  following the Effective  Date. If 77 WWLP and OTR are unable
to reach  agreement on the form of the Management  Agreement by such time,  this
Agreement shall be deemed to have terminated.






















































                                      -45-
<PAGE>
                                    EXHIBIT D
                                    ---------











                              AMENDED AND RESTATED

                               OPERATING AGREEMENT

                                       OF

                          77 WEST WACKER DRIVE, L.L.C.




                         Dated as of September 30, 1999







































                                      -46-
<PAGE>
                                TABLE OF CONTENTS

                                                                            PAGE
                                                                            ----

ARTICLE I  DEFINITIONS....................................................   1
    Section 1.1    Certain Definitions....................................   1

ARTICLE II  FORMATION.....................................................   6
    Section 2.1    Formation of Company...................................   6
    Section 2.2    Name of Company........................................   6
    Section 2.3    Purposes and Objectives................................   6
    Section 2.4    Term...................................................   6
    Section 2.5    Principal Place of Business............................   6

ARTICLE III  REPRESENTATIONS, WARRANTIES, AND ACKNOWLEDGMENTS.............   7
    Section 3.1    Representations of the Members.........................   7
            3.1.1  Due Organization.......................................   7
            3.1.2  Authorization..........................................   7
            3.1.3  Effect of this Agreement...............................   7
            3.1.4  Litigation.............................................   8
    Section 3.2    Indemnification by 77 WWLP.............................   8

ARTICLE IV  CAPITAL CONTRIBUTIONS.........................................   8
    Section 4.1    Capital Account........................................   8
            4.1.1  Establishment of Capital Accounts......................   8
    Section 4.2    Capital Contributions..................................   8
            4.2.1  Members' Initial Contributions.........................   8
            4.2.2  Other Contributions....................................   9
    Section 4.3    Consequences of Default in the Payment of Capital
                     Contributions........................................   9
            4.3.1  Non-Recourse...........................................   9
            4.3.2  Withdrawal of Contribution.............................   9
            4.3.3  Other Alternatives.....................................   9
    Section 4.4    Return of Capital......................................   10

ARTICLE V  ALLOCATIONS AND DISTRIBUTIONS..................................   11
    Section 5.1    Cash Distribution......................................   11
    Section 5.2    Distributions of Distributable Cash....................   11
    Section 5.3    Net Sale or Refinancing Proceeds.......................   11
    Section 5.4    Allocations of Profit..................................   12
    Section 5.5    Losses.................................................   12

ARTICLE VI  ACCOUNTING, TAXATION, AND OTHER MATTERS.......................   12
    Section 6.1    Company Taxable Year...................................   12
    Section 6.2    Location of Records; Inspection........................   13
    Section 6.3    Books of Account.......................................   13
    Section 6.4    Reports................................................   13
    Section 6.5    Taxation...............................................   13
    Section 6.6    Tax Returns and Audits.................................   16
    Section 6.7    Other Reports..........................................   16
    Section 6.8    Bank Accounts; Investments.............................   17
    Section 6.9    Insurance..............................................   17
    Section 6.10   Record Retention.......................................   17
    Section 6.11   UBTI...................................................   17


ARTICLE VII  MANAGEMENT OF THE COMPANY....................................   19
    Section 7.1    Administrative Member..................................   19
    Section 7.2    Duties of Administrative Member; Agents................   20
    Section 7.3    Major Decisions........................................   20
    Section 7.4    Non-Delegation.........................................   21


                                      -47-
<PAGE>
ARTICLE VIII  OTHER BUSINESS..............................................   22
    Section 8.1    Prime..................................................   22
    Section 8.2    OTR....................................................   23

ARTICLE IX  TRANSFERABILITY...............................................   23
    Section 9.1    General................................................   23
    Section 9.2    Transferee Not Member in Absence of Consent............   24
    Section 9.3    Sale of Membership Interest............................   24
    Section 9.4    Change of Control......................................   25

ARTICLE X  DISSOLUTION AND TERMINATION....................................   25
    Section 10.1   Dissolution............................................   25
    Section 10.2   Continuance of Company.................................   25
    Section 10.3   Termination............................................   26
    Section 10.4   Activities During Wind Up..............................   26
    Section 10.5   Liquidation............................................   26

ARTICLE XI  NO WAIVER.....................................................   27

ARTICLE XII  NO RIGHT TO PARTITION........................................   27

ARTICLE XIII  GENERAL.....................................................   27
    Section 13.1   Entirety of Agreement..................................   27
    Section 13.2   Notices................................................   27
    Section 13.3   Further Assurances.....................................   29
    Section 13.4   Applicable Law and Choice of Forum.....................   29
    Section 13.5   Counterparts...........................................   29
    Section 13.6   Headings...............................................   29
    Section 13.7   Waiver.................................................   29
    Section 13.8   Pronouns and Plurals...................................   29
    Section 13.9   Force Majeure..........................................   29
    Section 13.10  Section Numbers........................................   30
    Section 13.11  Notice of Litigation...................................   30
    Section 13.12  Severability...........................................   30
    Section 13.13  No Drafting Presumption................................   30
    Section 13.14  Third-Party Beneficiaries..............................   30
    Section 13.15  Remedies...............................................   30
    Section 13.16  Designation of Forum and Consent to Jurisdiction.......   30
    Section 13.17  Waiver of Jury Trial...................................   31
    Section 13.18  Binding Agreement......................................   31
    Section 13.19  Exculpation............................................   31
    Section 13.20  Like Kind Exchange.....................................   31
    Section 13.21  Performance/Holiday....................................   32

EXHIBIT A  Loan Agreements
EXHIBIT B  Determination of Fair Market Value
EXHIBIT C  Property Description
EXHIBIT D  Property Management and Leasing Agreement
EXHIBIT E  Annual Plans















                                      -48-
<PAGE>
                              AMENDED AND RESTATED
                               OPERATING AGREEMENT


     This Amended and Restated Operating Agreement ("Agreement") is entered into
as of the 30th day of September,  1999 (the "Effective  Date"),  between OTR, an
Ohio general  partnership  acting as nominee on behalf of and legally binding on
THE STATE TEACHERS  RETIREMENT SYSTEM OF OHIO ("OTR"), an instrumentality of the
State of Ohio, and PRIME GROUP REALTY,  L.P.  ("Prime"),  a limited  partnership
organized under the laws of the State of Illinois, both of which are referred to
as the "Members" and  individually as a "Member." In consideration of the mutual
promises contained herein the Members agree as follows:

                                    ARTICLE I

                                   DEFINITIONS

     Section 1.1 CERTAIN DEFINITIONS. Without limitation of the applicability of
other  defined terms used herein,  the following  terms shall have the following
meanings when used in this Agreement:

          1.1.1 "77WWLP" means 77 West Wacker Limited  Partnership,  an Illinois
     limited partnership.

          1.1.2  "77WWLP  Contributed  Assets" means all assets  contributed  by
     77WWLP to the Company pursuant to the Contribution Agreement.

          1.1.3 "Act" means the Delaware Limited Liability Company Act.

          1.1.4 "Additional  Capital  Contributions"  shall have the meaning set
     forth in Section 4.2.2.

          1.1.5  "Administrative  Member"  shall have the  meaning  set forth in
     Section 7.1.

          1.1.6 "Affiliate" means any Person directly or indirectly controlling,
     controlled by or under common control with another Person,  with control in
     such context meaning the possession,  directly or indirectly,  of the power
     to direct or cause the direction of the management and policies of another,
     whether  through  the  ownership  of  voting  securities,  by  contract  or
     otherwise.

          1.1.7  "Annual  Plans"  shall  have the  meaning  set forth in Section
     7.2(b).

          1.1.8  "Capital  Account"  shall have the meaning set forth in Section
     4.1.

          1.1.9 "Capital  Contribution"  means, with respect to any Member,  the
     amount of money and the initial fair market  value of any  property  (other
     than  money),  net of the  amount  of any debt to which  such  property  is
     subject,  contributed  to the Company  with  respect to the Interest in the
     Company held by such Member.

          1.1.10  "Capital  Transaction"  shall  mean (a) any  event or  Company
     transaction  (other  than  receipt  of a Capital  Contribution)  not in the
     ordinary  course of the Company's  business,  including (i) a sale or other
     disposition of all or substantially all of the Property, (ii) receipt of an
     installment of the outstanding  principal amount of or interest on purchase
     money obligations  accepted by the Company on any sale or other disposition
     of all or substantially all of the Company's assets, (iii) any damage to or


                                      -49-
<PAGE>
     condemnation,  destruction  or loss of all or any portion of the  Company's
     assets  resulting  in receipt  by the  Company  of  condemnation  awards or
     insurance proceeds on the basis of actual or constructive total loss (other
     than business interruption  insurance proceeds),  in excess of the amounts,
     if  any,  of  such  awards  or  proceeds  applied  to  the  acquisition  or
     reconstruction  of Company assets;  and (b) any financing or refinancing of
     all or substantially  all of the Company's assets or of indebtedness of the
     Company.

          1.1  "City  Agreement"  means  that  certain  restated   redevelopment
     agreement  dated  September  30, 1987 between the City of Chicago and Baird
     and  Warner-Higginbottom-Stein  & Company Venture as amended,  modified and
     supplemented as of the date hereof.

          1.1.11 "Code" means the Internal Revenue Code of 1986, as amended,  or
     any successor or replacement statute.

          1.1.12 "Common Equity" shall initially be $22,000,000 for each Member.

          1.1.13 "Company" means the limited  liability  company formed pursuant
     to this Agreement.

          1.1.14  "Contributing  Member"  shall  have the  meaning  set forth in
     Section 4.3.

          1.1.15 "Contribution Agreement" means the Contribution Agreement dated
     as of September 30, 1999, among OTR and 77WWLP.

          1.1.16  "Depreciation"  means for each  Company  taxable year or other
     period,  an amount equal to the depreciation,  amortization,  or other cost
     recovery  deduction  allowable for federal income tax purposes with respect
     to an asset for such year or other  period,  except that if an asset of the
     Company  is  reflected  on the books of the  Company  at a book  value that
     differs  from the  adjusted  tax basis of such  asset  pursuant  to Section
     1.704-1(b)(2)(iv)(d)    or   1.704-1(b)(2)(iv)(f)   of   the   Regulations,
     depreciation,  amortization,  or other cost  recovery  deductions  shall be
     computed for book purposes  with respect to such asset  pursuant to Section
     1.704-1(b)(2)(iv)(g) of the Regulations.

          1.1.17  "Distributable  Cash"  shall  have the  meaning  set  forth in
     Section 5.1.

          1.1.18  "Distribution  Date"  means the date which is twenty (20) days
     after the end of each month.

          1.1.19  "Effective  Date"  means September 30, 1999, which is the date
     closing occurs pursuant to Section 5.1 of the Contribution Agreement.

          1.1.20  "Fair  Market  Value"  means  the  value  of the  Property  as
     determined pursuant to Exhibit B hereto.

          1.1.21  "Interest"  or  "Percentage   Interest"  means  the  ownership
     interest of each Member in the Company and shall include its right to share
     in income, gain, profits,  losses and expense and to receive  distributions
     of  Company  assets  pursuant  to this  Agreement.  Immediately  after  the
     distribution  set  forth  in the  first  sentence  of  Section  5.1 and the
     contribution  of the  77WWLP  Contributed  Assets  and the OTR  Contributed
     Assets, the respective Interests of the Members shall be:

                  OTR                 50%
                  Prime               50%

          1.1.22 "Loan Agreements" means the loan documents set forth in Exhibit
     A.

                                      -50-
<PAGE>
          1.1.23  "Lock Out Period"  shall have the meaning set forth in Section
     9.3.

          1.1.24  "Member"  means each party  executing this Agreement and their
     successors  and  assigns  who are  admitted  pursuant  to the terms of this
     Agreement.

          1.1.25 "Net Sale or Refinancing  Proceeds" shall mean the net proceeds
     remaining from any Capital  Transaction  (including  any interest  received
     under any purchase money obligations accepted by the Company on any sale or
     other disposition of Company assets) after providing for the payment of all
     costs  and  expenses   related   thereto,   the  payment  for  any  capital
     expenditures  or  expenses  for which  such  proceeds  are to be used,  the
     satisfaction  of any  debt,  and the  setting  aside  of any  reserves  for
     creditors as reasonably determined by the Administrative Member.

          1.1.26  "Non-Contributing  Member" shall have the meaning set forth in
     Section 4.3.

          1.1.27 "OTR  Contributed  Assets" means the cash contributed by OTR to
     the Company pursuant to the Contribution Agreement.

          1.1.28 "Person" means an individual,  corporation,  limited  liability
     company, general partnership,  limited partnership,  voluntary association,
     joint stock company,  business  trust,  joint venture,  proprietorship,  or
     other legal entity, however constituted.

          1.1.29   "Preferred   Equity"  means   $66,000,000  of  OTR's  Capital
     Contribution less cumulative distributions pursuant to Section 5.3.2.

          1.1.30 "Priority Return" means an annual cumulative,  compounded, nine
     and one-half percent (9-1/2%) preferred return on the Preferred Equity.

          1.1.31  "Profits"  and "Losses"  and  reference to any item of income,
     gain,  loss or deduction  thereof mean,  for each Company  taxable year, an
     amount  equal to the  Company's  taxable  income  or loss for such  Company
     taxable  year,  determined  in  accordance  with Code  Section  703(a) (but
     including in taxable income or loss, for this purpose, all items of income,
     gain, loss or deduction  required to be stated separately  pursuant to Code
     Section 702(a)), with the following adjustments:

          i.   any income of the Company  exempt from federal income tax and not
               otherwise  taken  into  account  in  computing  Profits or Losses
               pursuant to this definition shall be added to such taxable income
               or loss;

          ii.  any  expenditures  of  the  Company  described  in  Code  Section
               705(a)(2)(B)  (or  treated  as  expenditures  described  in  Code
               Section    705(a)(2)(B)    pursuant   to   Regulations    Section
               1.704-1(b)(2)(iv)(i))  and not  otherwise  taken into  account in
               computing  Profits or Losses pursuant to this definition shall be
               subtracted from such taxable income or loss;

          iii. in the event the gross fair market value of any Company  asset is
               adjusted in accordance with the  Regulations,  the amount of such
               adjustment  shall be taken into  account as gain or loss from the
               disposition  of such asset for purposes of  computing  Profits or
               Losses;

          iv.  gain or loss resulting  from any  disposition of any asset of the
               Company  with  respect  to which gain or loss is  recognized  for
               federal income tax purposes shall be computed by reference to the


                                      -51-
<PAGE>
               gross fair market value of the asset disposed of, notwithstanding
               that the adjusted tax basis of such asset  differs from its gross
               fair market value;

          v.   in lieu of the depreciation,  amortization and other cost recover
               deductions taken into account in computing such taxable income or
               loss,  there shall be taken into  account  Depreciation  for such
               Company taxable year or other period;

          vi.  to the  extent an  adjustment  to the  adjusted  tax basis of any
               Property   is   required   pursuant   to   Regulations    Section
               1.704-1(b)(2)(iv)(m)(4)  to be taken into account in  determining
               Capital Accounts,  the amount of such adjustment shall be treated
               either as an item of gain (if the adjustment  increases the basis
               of the asset) or an item of loss (if the adjustment decreases the
               basis of the  asset) in  respect of such asset and shall be taken
               into account for purposes of computing Profits and Losses; and

          vii. notwithstanding   any  other  provision  of  this  definition  of
               "Profits" and  "Losses," any items which are specially  allocated
               pursuant to Section 6.5 hereof shall not be taken into account.

          1.1.32.  "Property"  means the  fifty  story  Class A office  building
     located at the southeast corner of West Wacker Drive and North Clark Street
     in Chicago,  Illinois  and  containing  approximately  944,556 net rentable
     square feet of office  space,  an  approximately  12,288 square foot health
     club  facility  in an  air  rights  parcel  adjacent  to the  Property,  an
     approximately  4,800  square foot  cafeteria  style  restaurant,  45 indoor
     parking  spaces,  certain air rights and the  benefits of a parking  rights
     agreement and a skywalk agreement more fully described in Exhibit C hereto.

          1.1.33.   "Property   Management  and  Leasing  Agreement"  means  the
     agreement set forth in Exhibit D hereto.

          1.1.34.  "Readjusted  Equity"  shall  mean the  Common  Equity  of the
     Members restated to reflect the Fair Market Value of the Property.

          1.1.35.   "Regulations"  mean  the  temporary  and  final  income  tax
     regulations promulgated under the Code from time to time.

                                   ARTICLE II

                                    FORMATION

     Section  2.1  FORMATION  OF  COMPANY.  The  Company was formed as a limited
liability  company  pursuant to the Act,  effective August 9, 1999. The original
Member now desires to admit OTR as a Member, to distribute its interest to Prime
(its  sole  member),  to  confirm  Prime  as  a  Member  as  a  result  of  such
distribution,  to withdraw as a Member  itself as a result of such  distribution
and to confirm,  amend and restate the  Agreement in its  entirety.  The rights,
privileges,  liabilities  and obligations of the Members shall be as provided in
the Act, except as herein expressly stated to the contrary in this Agreement.

     Section  2.2  NAME OF  COMPANY.  The name of the  Company  shall be 77 West
Wacker Drive,  L.L.C.  The  Administrative  Member shall cause a certificate  of
formation  that complies with the  requirements  of the Act to be properly filed
with the Delaware Secretary of State. In the future,  the Administrative  Member
shall execute such further  documents  (including  amendments to the articles of
organization)  and take such further action as shall be appropriate or necessary
to comply with the  requirements  of law for the  formation  and  operation of a
limited liability company in all states and counties where the Company elects to
carry on its business.


                                      -52-
<PAGE>
     Section 2.3 PURPOSES AND  OBJECTIVES.  The purposes of the Company shall be
to engage  primarily in the ownership,  leasing and operation of the Property in
accordance with the terms and provisions of this Agreement and to engage in such
other activities as may be related, incident or ancillary thereto.

     Section  2.4 TERM.  The  Company  shall  commence as of the date hereof and
continue in existence in perpetuity,  or until terminated in accordance with the
terms of this Agreement.

     Section 2.5 PRINCIPAL PLACE OF BUSINESS. The principal place of business of
the Company  shall be at 77 West Wacker  Drive,  Suite 3900,  Chicago,  Illinois
60601 or such other location as the Administrative  Member shall determine.  The
Administrative  Member shall give reasonable  prior written notice of any change
in such principal place of business to the Members.  The name and address of the
registered agent in Delaware is Corporation  Trust Company,  1209 Orange Street,
Wilmington, New Castle County, Delaware 19801.

                                   ARTICLE III

                REPRESENTATIONS, WARRANTIES, AND ACKNOWLEDGMENTS

     Section 3.1  REPRESENTATIONS  OF THE MEMBERS.  Each Member  represents  and
warrants to the other:

          3.1.1  Due  Organization.  Such  Member  is  duly  organized,  validly
     existing  and  in  good  standing  under  the  laws  of  the  state  of its
     organization  and has the requisite power and authority (a) to carry on its
     business  as  presently  conducted  and to  own or  hold  under  lease  its
     properties, where the failure to have such power and authority would have a
     material  adverse  effect on its ability to perform its  obligations  under
     this  Agreement,  and (b) to enter into and perform its  obligations  under
     this Agreement.

          3.1.2 Authorization.  The execution,  delivery and performance by such
     Member of this Agreement have been duly authorized by all necessary  action
     on the  part of such  Member.  This  Agreement  has been  duly  authorized,
     executed  and  delivered  by such Member and is a legal,  valid and binding
     obligation  of such Member,  enforceable  against such Member in accordance
     with its terms,  except as such enforceability may be limited by applicable
     bankruptcy, insolvency, reorganization,  liquidation, moratorium or similar
     laws affecting  creditors' or lessors'  rights  generally and except as the
     application of general  equitable  principles may limit the availability of
     certain remedies.

          3.1.3 Effect of this Agreement.  Neither the execution and delivery of
     this  Agreement,  nor the  consummation  of the  transactions  contemplated
     hereby nor  compliance  by such Member with any of the  provisions  hereof,
     will:  (a)  conflict  with or result in a breach  of any  provision  of the
     constituent  documents of such Member;  (b) require the approval or consent
     of, or filing or registration with, any foreign,  federal,  state, local or
     other  governmental  or  regulatory  body or the approval or consent of any
     other  Person the failure of which to make or obtain  would have a material
     adverse  effect on the ability of such  Member to perform  its  obligations
     under this Agreement; (c) violate any provision of any law or regulation or
     violate,  breach  or,  with  the  giving  of  notice  or  passage  of time,
     constitute  an event of default (or give rise to any right of  termination,
     cancellation  or  acceleration)  under  any of  the  terms,  conditions  or
     provisions of any note, bond, mortgage,  indenture,  license,  agreement or
     other instrument or obligation to which such Member is a party, or by which
     it  may  be  bound,  which  violation,  breach  or  default  (or  right  of
     termination,  cancellation or  acceleration)  would have a material adverse



                                      -53-
<PAGE>
     effect on the ability of such Member to perform its obligations  under this
     Agreement and the transactions  contemplated hereby,  except in the case of
     (b) and (c) as to which requisite waivers or consents have been obtained.

          3.1.4 Litigation.  There is no action,  suit or proceeding pending or,
     to the knowledge of such Member,  threatened  against such Member which, if
     adversely determined could, individually or in the aggregate, reasonably be
     expected to materially  and adversely  affect the ability of such Member to
     perform its obligations under this Agreement.

     3.2  INDEMNIFICATION  BY PRIME.  Prime shall  indemnify OTR for any and all
expenses, costs and liability with respect to activity of the Company which have
accrued  prior to the  Effective  Date of this  Amended and  Restated  Operating
Agreement of the Company.

                                   ARTICLE IV

                              CAPITAL CONTRIBUTIONS

     Section 4.1 CAPITAL ACCOUNT.

          4.1.1  Establishment  of  Capital  Accounts.  A capital  account  (the
     "Capital Account") shall be established and maintained for each Member. The
     Capital Account of each Member shall be (a) credited with any income of the
     Company  allocated to such Member  pursuant to the terms of this  Agreement
     and the amount of cash and net fair  market  value (as set forth in Section
     4.2 for the initial Capital  Contributions and as reasonably  determined by
     the   Administrative   Member  in  writing  for  any   subsequent   Capital
     Contributions)  of any  property  contributed  by such  Member  under  this
     Agreement;  (b)  debited  with the  amount of cash and the net fair  market
     value (as reasonably determined by the Administrative Member in writing) of
     any property  distributed to such Member by the Company  (including without
     limitation the  distribution to 77WWLP described in Section 5.1 hereto) and
     with any deductions,  losses and  expenditures of the Company  allocated to
     such Member pursuant to the terms of this Agreement, and (c) otherwise kept
     in conformance with Regulations Sections 1.704-1(b) and 1.704-2.

     Section 4.2 CAPITAL  CONTRIBUTIONS.  The Members  shall make the  following
Capital Contributions to the Company:

          4.2.1 Members' Initial Contributions

               (a) 77WWLP has contributed to the Company all of its right, title
          and  interest  in and to the  77WWLP  Contributed  Assets.  77WWLP was
          credited with a Capital  Contribution  equal to $110,000,000,  as such
          amount may be adjusted in accordance with the Contribution  Agreement,
          such  amount  representing  the net fair  market  value of the  77WWLP
          Contributed Assets.

               (b) OTR has contributed on the date hereof to the Company the OTR
          Contributed Assets. OTR shall be credited with a Capital  Contribution
          equal to  $88,000,000,  as such amount may be  adjusted in  accordance
          with the Contribution  Agreement,  such amount representing the amount
          of the OTR Contributed Assets. This Capital Contribution shall be made
          in  accordance  with the  terms  and  provisions  of the  Contribution
          Agreement.

               (c)  77WWLP  Interest  was then  transferred  to Prime with Prime
          succeeding to 77WWLP Capital Account.





                                      -54-
<PAGE>
          4.2.2 Other  Contributions.  If additional  capital is required by the
     Company as determined  unanimously  by the Members,  the Members shall make
     such   additional   capital    contributions   (the   "Additional   Capital
     Contribution") in proportion to their respective Interests.

     Section 4.3  CONSEQUENCES OF FAILURE TO PAY CAPITAL  CONTRIBUTIONS.  If any
Member (the "Non Contributing  Member") fails to make any Capital  Contribution,
or any portion  thereof,  which such Member is required to make pursuant to this
Agreement   within  30  days  after   agreement  to  make   Additional   Capital
Contributions,  then the Lock Out Period  shall expire and the other Member (the
"Contributing  Member")  may make such  Capital  Contribution,  or such  portion
thereof  which  the  Non-Contributing   Member  has  failed  to  make,  and  the
Contributing  Member shall have the following remedies as its sole and exclusive
remedies under the Agreement, at law and in equity:

     4.3.1 NON-RECOURSE. The Contributing Member may exercise any and all rights
and remedies  provided in this  Agreement,  but not any other  remedies that are
available  at  law  or in  equity,  to  enforce  the  Non-Contributing  Member's
obligation  to make  such  Capital  Contributions  or for  damages  suffered  or
incurred by the  Contributing  Member or the Company by reason of the failure of
the  Non-Contributing  Member to  contribute.  Notwithstanding  anything  to the
contrary contained in this Agreement,  no assets of the Non-Contributing  Member
other than its Interest  shall be subject to any lien or recourse as a result of
the  failure  of such  Non-Contributing  Member  to  make  such  unpaid  Capital
Contributions.

     4.3.2 WITHDRAWAL OF CONTRIBUTION. In the case of any failure to timely make
any Capital Contribution, the Contributing Member may withdraw its share of such
requested  Capital  Contribution  by  delivery  of notice to such  effect to the
Company and the Non-Contributing Member.

     4.3.3  OTHER  ALTERNATIVES.  In the case of any  failure to timely make any
Capital  Contribution,  as an alternative to the remedies  provided for above in
Section 4.3.2,  any  Contributing  Member may  contribute  the  Non-Contributing
Member's share of such requested  Capital  Contributions,  and the  Contributing
Member may elect treatment of its contribution on behalf of the Non-Contributing
Member  pursuant  to clause (a) or (b),  below,  by  delivery  of notice of such
election to the Company and the Non-Contributing Member.

          (a) Loan: A Contributing  Member may treat such contribution as a loan
     to the Non-Contributing  Member, in which event the Non-Contributing Member
     shall be indebted to the Contributing  Member in the principal amount equal
     to the Capital  Contribution made by such Contributing  Member on behalf of
     the  Non-Contributing  Member, which loan shall bear interest at the lesser
     rate  of  fifteen   percent  (15%)  per  annum  or  the  maximum  rate  the
     Contributing  Partner is  permitted to charge by law,  compounded  monthly,
     which loan shall be due and payable in full on the third  anniversary after
     the  funding  of  such  Capital  Contribution  or  greater  period  as  the
     Contributing  Member may specify in its notice subject however to the terms
     of Section  4.3.1.  Any  Contributing  Member  having  elected to treat its
     contribution  as a loan pursuant to this clause (a) may change its election
     after such third  anniversary,  by written  notice to the  Non-Contributing
     Member, to elect treatment under clause (b) below.

          (b) Squeeze-Down: A Contributing Member may elect to decrease (but not
     below zero) the Percentage Interest of the Non-Contributing Member pursuant
     to this clause  (b). If the  Contributing  Member so elects,  the  Member's
     Percentage Interest shall thereafter by determined for the Non-Contributing
     Member by dividing its Readjusted Equity by the total Readjusted Equity and
     the applicable  Additional Capital  Contribution of the Contributing Member
     and for the  Contributing  Member  by  dividing  the sum of its  Readjusted
     Equity and the applicable Additional Capital Contribution by the sum of the
     total Readjusted Equity and the applicable Additional Capital Contribution.

                                      -55-
<PAGE>
     Section 4.4 RETURN OF CAPITAL.  No Member shall have any personal liability
for the repayment of the Capital Contributions of any Member except as otherwise
provided in this  Article IV. No Member shall be entitled to the  withdrawal  or
return  of  its  Capital  Contributions  except  to the  extent,  if  any,  that
distributions  made  pursuant  to this  Agreement  or upon the winding up of the
Company may be  considered  as such by  operation  of law,  and then only to the
extent  provided  for in this  Agreement.  Except as set forth in  Article V, no
Member  shall have  priority  over any other  Member  either as to the return of
capital or as to profits,  losses or distributions or be entitled to receive any
interest on its Capital  Contributions or to receive or demand any property from
the Company other than cash.

                                    ARTICLE V

                          ALLOCATIONS AND DISTRIBUTIONS

     Section  5.1  CASH  DISTRIBUTION.  The OTR  Contributed  Assets  have  been
distributed to 77WWLP or its Assignee pursuant to Section 13.20 hereof.  Subject
to Section 13.20 hereto, such contribution and distribution shall be treated for
federal  and state  income tax  purposes  as a cash  contribution  by OTR to the
Company  followed by a part sale,  part  capital  contribution  by 77WWLP of the
77WWLP Contributed Assets to the Company. All subsequent  distributions shall be
made from cash of the Company  remaining after repayment of all amounts then due
and payable  pursuant to the Loan Agreements and other expenses,  liabilities of
the Company then due and payable and after establishment of such reserves as the
Administrative  Member may  reasonably  determine  for  specific  purposes  (the
"Distributable  Cash").  During the existence of the Company, no Member shall be
entitled to receive as  distributions  from the Company any asset of the Company
other than cash.

     Section 5.2 DISTRIBUTIONS OF DISTRIBUTABLE  CASH.  Distributable Cash as of
each Distribution Date shall be distributed as follows:

          5.2.1 First, to OTR until the cumulative  distributions to OTR for the
     current and all prior Company taxable years pursuant to this Section 5.2.1,
     and Section 5.3.1 equals the Priority Return; and

               5.2.2 The balance,  if any,  shall be distributed to the Members,
          pro rata, in accordance with their Percentage Interests.

     Section 5.3 NET SALE OR REFINANCING PROCEEDS.  Except as otherwise provided
herein or upon dissolution and termination  under Article X, the  Administrative
Member  shall  cause  the  Company  to  distribute  all Net Sale or  Refinancing
Proceeds  not later than five (5)  business  days after the closing  date of the
Capital  Transaction(s)  giving  rise to such  proceeds  to the  Members  in the
following order and priority:

          5.3.1 First, to OTR until the cumulative  distributions to OTR for the
     current and all prior Company  taxable years pursuant to this Section 5.3.1
     and Section 5.2.1 equals the Priority Return;

          5.3.2 Second, to OTR until the cumulative distributions to OTR for the
     current and all prior Company  taxable years pursuant to this Section 5.3.2
     equals the Preferred Equity; and

          5.3.3 The balance,  if any shall be  distributed  to the Members,  pro
     rata in accordance with their Percentage Interest.

     Section 5.4  ALLOCATIONS OF PROFIT.  Except as otherwise  provided  herein,
Profits of the Company shall be allocated in the following order of priority:




                                      -56-
<PAGE>
          5.4.1 First, to the Members in proportion to the cumulative unreversed
     Losses  allocated  to each  Member  pursuant  to  Section  5.5.3  until the
     cumulative Profit allocated pursuant to this Section 5.4.1 are equal to the
     cumulative  Losses  allocated to such Members  under  Section 5.5.3 for all
     prior Company taxable years;

          5.4.2 Second, to OTR, in an amount equal to the excess, if any, of the
     Priority  Return  as of the end of  such  Company  taxable  year  over  the
     cumulative  allocations of Profit allocated  pursuant to this Section 5.4.2
     (net of  allocations of Losses made to OTR under Section 5.5.2) made to OTR
     for all prior Company taxable years; and

          5.4.3 The balance,  if any, to each Member,  pro rata,  in  accordance
     with such Member's Interest.

     Section 5.5 LOSSES.  Except as  otherwise  provided  herein,  Losses of the
Company shall be allocated in the following order and priority:

          5.5.1 First, to each Member in accordance with such Member's  Interest
     until the cumulative  Losses  allocated  pursuant to this Section 5.5.1 for
     the current  and all prior  Company  taxable  years  equals the  cumulative
     Profits,  if any, allocated pursuant to Section 5.4.3 for all prior Company
     taxable years;

          5.5.2 Second,  to OTR,  until the cumulative  Losses  allocated to OTR
     pursuant  to this  Section  5.5.2 for the  current  and all  prior  Company
     taxable years equals the cumulative  Profits allocated  pursuant to Section
     5.4.2 for all prior Company taxable years; and

          5.5.3 The balance,  if any, shall be allocated  fifty percent (50%) to
     OTR and fifty percent (50%) to Prime.

                                   ARTICLE VI

                     ACCOUNTING, TAXATION, AND OTHER MATTERS

     Section 6.1 COMPANY  TAXABLE YEAR. The taxable year of the Company shall be
the calendar year. The first taxable year of the Company shall begin on the date
hereof and end on December 31, 1999.

     Section  6.2  LOCATION  OF  RECORDS;  INSPECTION.  The books,  records  and
accounts for the Company shall be kept and maintained at the principal office of
the Administrative  Member.  Each Member, at its own expense and upon reasonable
notice,  shall have the right and power to examine and  inspect,  or cause to be
examined and inspected,  at any and all reasonable times, the books, records and
accounts of the Company and any tax returns  prepared  for the Company  prior to
the filing thereof.

     Section 6.3 BOOKS OF ACCOUNT. The books of account for the Company shall be
maintained by the  Administrative  Member on an accrual basis in accordance with
generally acceptable accounting principles.

     Section  6.4  REPORTS.  As soon as  practicable  following  the end of each
Company  taxable  year and in any event  within the time  specified  below,  the
Administrative  Member  shall  cause to be  prepared  on both a cash and accrual
basis and delivered to each Member:

          6.4.1 As soon as  practical  but in no event  later  than one  hundred
     twenty (120) days  following the end of such Company  taxable year a report
     containing  financial  statements  of the Company  including a statement of
     each Member's  Capital  Account.  The costs of such report shall be paid by
     the Company.


                                      -57-
<PAGE>
          6.4.2 As soon as  practical  but in no event  later  than one  hundred
     twenty (120) days  following the end of such Company  taxable year (or such
     later time as the Administrative  Member shall permit), a report containing
     information  regarding changes to the Capital Account of each Member during
     such  Company   taxable   year,   including   (a)  the  amount  of  Capital
     Contributions credited to each Member's Capital Account during such Company
     taxable  year,  (b) any  distributions  received  by a Member  during  such
     Company  taxable  year under  this  Agreement,  and (c) any items,  such as
     Profits or Losses from the Company's activities, allocated to each Member's
     Capital Account during such Company taxable year.

          6.4.3  Such other  reports  and  information  as either  Member  shall
     reasonably request.

     Section 6.5 TAXATION.

          6.5.1 The  parties  intend  that the  Company  shall be  treated  as a
     partnership for federal, state and local income and other tax purposes. The
     Members  agree to  cooperate  in the taking of all  action,  including  the
     amendment  of this  Agreement  and the  execution  of other  documents,  if
     required, to qualify for and receive such tax treatment.

          6.5.2 Notwithstanding the provisions of Section 5.3:

               (a) If there is a net  decrease  in  "partnership  minimum  gain"
          (within the meaning of Regulations  Section  1.704-2(d)) for a Company
          taxable year,  then,  there shall be allocated to each Member items of
          income  and gain for that year  (and,  if  necessary,  for  succeeding
          years)  equal to that  Member's  share of the net  decrease in minimum
          gain (within the meaning of Regulations  Section  1.704-2(g)(2)).  The
          foregoing is intended to be a "minimum gain charge back"  provision as
          described in Regulations  Section  1.704-2(f) and shall be interpreted
          and  applied  in all  respects  in  accordance  with that  Regulations
          Section.

               (b) If during a Company  taxable  year there is a net decrease in
          partner  nonrecourse  debt minimum gain (as  determined  in accordance
          with  Regulations  Section  1.704-2(i)(3)),  then,  in addition to the
          amounts,  if any, allocated pursuant to the preceding  paragraph,  any
          Member with a share of that  partner  nonrecourse  debt  minimum  gain
          (determined in accordance with Regulations  Section  1.704-2(i)(5)) as
          of the beginning of the Company  taxable year shall be allocated items
          of income and gain for that year (and,  if necessary,  for  succeeding
          years)  equal  to that  Member's  share  of the net  decrease  in such
          partner  nonrecourse  minimum gain.  The foregoing is intended to be a
          "chargeback of partner  nonrecourse  debt minimum gain" as required by
          Regulations Section 1.704-2(i)(4) and shall be interpreted and applied
          in all respects in accordance with such Regulations Section.

               (c) If during any  Company  taxable  year of the Company a Member
          unexpectedly  receives  an  adjustment,   allocation  or  distribution
          described in Regulations Section 1.704-1(b)(2)(ii)(d)(4), (5), or (6),
          which  causes or increases a deficit  balance in the Member's  Capital
          Account in excess of that which the Member is  obligated to restore or
          deemed  obligated to restore  pursuant to the penultimate  sentence of
          Regulation  Sections   1.704-2(g)  and  1.704-2(i),   there  shall  be
          allocated to such Member items of income and gain (consisting of a pro
          rata portion of each item of Company  income,  including gross income,
          and  gain for  such  year)  in an  amount  and  manner  sufficient  to
          eliminate such deficit  balance as quickly as possible.  The foregoing
          is intended to be a "qualified  income offset"  provision as described
          in Regulations Section 1.704-1(b)(2)(ii)(d),  and shall be interpreted
          and  applied  in all  respects  in  accordance  with such  Regulations
          Section.
                                      -58-
<PAGE>
               (d) If the  allocation  of any item of loss or deduction  for any
          Company  taxable year would cause or increase a deficit balance in the
          Capital  Account of any Member as of the end of such  Company  taxable
          year in excess of that  which the  Member is  obligated  to restore or
          deemed  obligated to restore  pursuant to the penultimate  sentence of
          Regulation Sections 1.704-2(g) and 1.704-2(i), then, to the extent the
          allocation  of such item of loss or deduction  would have such effect,
          it shall  instead be allocated  (a) first,  to the other Member to the
          extent  that such  allocation  reduces  such  other  Member's  Capital
          Account to, but not cause such deficit  Capital  Account to such other
          Member,  and (b)  thereafter,  in accordance  with Section 5.5.3.  For
          purposes of this paragraph (d), a Member's  Capital  Account shall not
          be    reduced    for    items    listed   in    Regulations    Section
          1.704-1(b)(2)(ii)(d)(4),  (5) and (6) for purposes of determining  (i)
          whether the  allocation of any item of loss or deduction for a Company
          taxable year would cause or increase a deficit  balance in the Capital
          Account of any Member as of the end of such Company  taxable year, and
          (ii) the amount of items of loss or  deduction  that can be  specially
          allocated  pursuant to this  paragraph (d) to the other Member without
          reducing such other Member's Capital Account below zero.

               (e)  Notwithstanding  anything to the  contrary  in this  Section
          6.5.2,  any item of  deduction,  loss,  or Code  Section  705(a)(2)(B)
          expenditure that is attributable to "partner  nonrecourse  debt" shall
          be allocated in  accordance  with the manner in which the Members bear
          the economic risk of loss for such debt (determined in accordance with
          Regulations Section 1.704-2(i)).

               (f)  Beginning  in the  first  taxable  year in which  there  are
          allocations  of  "nonrecourse  deductions"  (as  described  in Section
          1.704-2(b) of the  Regulations)  and  throughout  the full term of the
          Company such  deductions  shall be allocated to the Members as part of
          the Profit or Losses allocated for such period.

               (g) All  recapture of income tax  deductions  resulting  from the
          sale or  disposition  of Company  property  shall be  allocated to the
          Member  or  Members  to whom  the  deduction  that  gave  rise to such
          recapture  was  allocated  hereunder to the extent that such Member is
          allocated  any  gain  from  the  sale  or  other  disposition  of such
          property.

               (h) Any  credit  or  charge to the  Capital  Account  of a Member
          pursuant to paragraphs  (a), (b), (c), (d), (e) or (f) of this Section
          6.5.2 shall be taken into account by computing subsequent  allocations
          of Profits and Losses,  so that the net amount of any items charged or
          credited to Capital  Accounts  pursuant  to  Sections  5.4 and 5.5 and
          pursuant to paragraphs (a), (b), (c), (d), (e) and (f) of this Section
          6.5.2 shall, to the extent  possible,  be equal to the net amount that
          would  have been  allocated  to the  Capital  Account  of each  Member
          pursuant  to the  provisions  of  Sections  5.4 and 5.5 if the special
          allocations  required by paragraphs (a), (b), (c), (d), (e) and (f) of
          this Section 6.5.2 had not occurred.

               (i)  In  any  Company  taxable  year  in  which  the  Company  is
          liquidated  pursuant  to Article V,  items of income,  gain,  loss and
          deduction  shall,  to the extent  necessary,  be  reallocated  between
          Members in order to permit the  liquidating  distributions  made under
          Sections 10.5.3 and 10.5.4.

               (j) In  accordance  with  Section  704(c)  of the  Code  and  the
          applicable Regulations  thereunder,  income, gain, loss, deduction and
          tax depreciation  with respect to any property  contributed to capital


                                      -59-
<PAGE>
          of the Company, or with respect to any property which has a book basis
          different  than its  adjusted  tax basis,  shall,  solely for  federal
          income tax  purposes  be  allocated  between the Members so as to take
          into  account any  variation  between the  adjusted  tax basis of such
          property to the Company and the book basis of such property. All items
          of Company  income,  gain,  loss,  deduction and any other  allocation
          otherwise  provided  for shall be divided  between  the Members in the
          same priority in proportion  as they share gain,  income,  or loss, as
          the case may be for such year.

     Section 6.6 TAX RETURNS AND AUDITS. The Administrative Member shall prepare
or cause to be prepared and timely file (after  giving  effect to all  extension
periods) all  federal,  state and local income and other tax returns and reports
as may be required as a result of the business of the Company. If requested by a
Member not less than fifteen (15) days prior to the date (as  extended) on which
the Company  intends to file its federal  income tax return or any state  income
tax return, the return proposed to be filed by the  Administrative  Member shall
be furnished to the Members for review and comments. In addition,  not less than
thirty (30) days after the date on which the Company  actually files its federal
income tax return or any state income tax return,  a copy of the return so filed
by the Administrative Member shall be furnished to the Members.  Prime is hereby
designated  the  tax  matters  partner  under  Section  6231  of the  Code.  The
Administrative  Member  shall  promptly  notify the Members if any tax return or
report of the  Company is  audited or if any  adjustments  are  proposed  by any
governmental body. In addition, the Administrative Member shall promptly furnish
to the Members periodic reports,  not less often than quarterly,  concerning the
status  of any  such  proceeding.  Without  the  written  consent  of all of the
Members,  the tax matters partner, in its capacity as such, shall not extend the
statute of limitations,  file a request for administrative adjustment, file suit
concerning any tax refund or deficiency  relating to any Company  administrative
adjustment or enter into any settlement  agreement  relating to any Company item
of income,  gain, loss,  deduction or credit for any Company taxable year of the
Company.

     Section 6.7 OTHER  REPORTS.  The  Administrative  Member shall  prepare and
file,  or cause to be prepared and filed,  all reports  prescribed  by any other
commission  or  governmental  agency  having  jurisdiction  over the business or
properties of the Company or required by the Loan Agreements, the costs of which
shall be paid by the Company.

     Section 6.8 BANK ACCOUNTS; INVESTMENTS.

          (a) The  Administrative  Member  shall  cause the  Company to open and
     maintain bank accounts at banks selected by the Administrative  Member. All
     funds of every kind and nature received by the Company,  including  Capital
     Contributions,  loan proceeds and operating receipts, shall be deposited in
     such bank  accounts.  The  Administrative  Member  shall  give the  Members
     written  notification  of the  banks at which  Company  bank  accounts  are
     maintained.  Signatories for such accounts shall be authorized from time to
     time in writing by the Administrative Member.

          (b) The  Company  may make such  investments  as are  approved  by the
     Administrative  Member provided such  investments are not prohibited by any
     Member's organizational documents; provided, however, that such investments
     shall not preclude the timely  distribution  of  Distributable  Cash as set
     forth in Article V; and provided,  further,  that any investment of working
     capital shall not preclude the timely payment of Company  obligations  when
     and as due.

     Section 6.9 INSURANCE.  The Administrative  Member shall determine the type
and levels of insurance coverage to be obtained and maintained by the Company to
protect the Company's properties and businesses against loss and liability.


                                      -60-
<PAGE>
     Section 6.10 RECORD RETENTION.  The  Administrative  Member shall cause all
records that are  required  under this  Agreement  or under any other  agreement
entered into  pursuant to this  Agreement to be retained by the Company for such
period of time as required by law, but in no event for less than seven years.

     Section 6.11. UBTI.  Notwithstanding  anything to the contrary contained in
other  Sections  of this  Agreement,  the  Administrative  Member  agrees to use
commercially reasonable efforts not to do any of the following:

          (a) enter into any contract for the acquisition or improvement of real
     property where the price for such acquisition or improvement is not a fixed
     amount  determined as of the date of the  acquisition  or the completion of
     such improvement;

          (b) incur any indebtedness  with respect to the Property the amount of
     which, or of any other amount payable with respect to such indebtedness, or
     the time for making any payment of any such amount, depends, in whole or in
     part, on any revenue, income or profits derived from the Property;

          (c)  subject to the  exception  in Section  514(c)(9)(G)  of the Code,
     lease the Property or any part  thereof to the Person  selling the Property
     to the Company or to any Person  related to the selling  Person  within the
     meaning of Section 267(b) or 707(b) of the Code;

          (d) knowingly lease the Property or any part thereof;

               (i) to any person who is  related,  within the meaning of Section
          4975(e)(2)(C), (E), or (G) of the Code, to OTR; or

               (ii) to any person who is related,  within the meaning of Section
          4975(e)(2)(F)  or (H) of the Code, to any person  described in Section
          6.11(d)(i) above;

          (e) enter into any lease or  arrangement  with respect to the Property
     or any part thereof;

               (i) which would provide for rent or other compensation for use or
          occupancy  of the  Property  that depends in whole or in part upon the
          income or  profits  derived by any  person  from the  leased  property
          (other than an amount based upon a fixed  percentage or percentages of
          receipts or sales;

               (ii) under  which fifty  percent  (50%) or more of the total rent
          receivable by the Company would be attributable to incidental personal
          property within the meaning of Section 512(b) of the Code.

          (f) incur any indebtedness  with respect to the Property from a person
     described in Section  6.11(c)  hereof or knowingly  incur any  indebtedness
     with respect to the  Property  from a person  described in Section  6.11(d)
     hereof; or

          (g) following the date of this  Agreement,  knowingly take any action,
     or permit any action to be taken,  that would  subject any Affiliate of OTR
     to the tax on unrelated  business taxable income under Section 511, et seq.
     of the Code  ("UBTI")  unless in each case OTR has  consented in writing to
     any transaction that might cause such tax to be imposed.  If OTR refuses to
     consent in writing to a particular transaction, and such refusal causes the
     Administrative Member to violate any provision of this Agreement other than
     this Section 6.11,  then such  violation  shall not  constitute a breach of
     this  Agreement.  Upon OTR's refusal to consent,  OTR shall have the rights
     set forth below in this Section 6.11.



                                      -61-
<PAGE>
     The  Administrative  Member shall use  commercially  reasonable  efforts to
comply with such other  requirements in connection with the avoidance of UBTI by
OTR or any Affiliate of OTR as OTR's counsel may  reasonably  request in writing
from time to time, but under no circumstances shall the Administrative Member be
required  to comply  with such  requirements  if doing so would  have a material
adverse effect on the Administrative  Member or Prime;  provided,  however, upon
the Administrative  Member's failure to comply with such requirements,  the Lock
Out Period shall  terminate in one hundred  twenty (120) days from OTR's refusal
to consent.  Because the  provisions of this Section 6.11 are for the benefit of
OTR,  only OTR shall  have the right,  exercisable  in its sole  discretion,  to
approve the waiver of the  application  of this  Section 6.11 to any incident or
transaction  (and no other  Member  shall have the right to approve or otherwise
affect such  waiver).  Any  instrument  purporting  to be such a waiver shall be
invalid  unless it is signed by OTR.  Any such  waiver  shall not  constitute  a
permanent  waiver of this  Section  6.11 and shall apply only to the incident or
transaction  specified in the waiver;  and any subsequent or similar incident or
transaction  shall require  another waiver as specified  above.  Notwithstanding
anything herein to the contrary, if any provision of the Code or Regulations (as
written as of the date of this Agreement) is amended,  superseded,  or otherwise
modified  such that any lease  agreement,  loan  agreement or other  arrangement
(including this Agreement)  existing as of the date of this Agreement  violates,
or causes the  Administrative  Member to violate,  the  provisions  of the first
sentence of this Section 6.11, any adverse consequence shall be born entirely by
OTR; provided,  however,  the Administrative  Member agrees to notify OTR of any
known violation as soon as possible and to use commercially  reasonable  efforts
to  attempt  to cure  such  violation,  but  under no  circumstances  shall  the
Administrative  Member be required to cure any such violation if it would have a
material adverse effect on the Administrative Member or Prime.

                                   ARTICLE VII

                            MANAGEMENT OF THE COMPANY

     Section 7.1  ADMINISTRATIVE  MEMBER.  The  Administrative  Member initially
means Prime and  thereafter  any  successor  manager as may be  appointed by the
Members.  Subject to the express limitations set forth in this Agreement and the
Property Management and Leasing Agreement,  the Administrative Member shall have
(a) the full,  complete and  exclusive  authority  and  discretion to manage the
operations  and affairs of the Company and to make all  decisions  regarding the
business  of the  Company,  (b) all the rights  and  powers of a  Administrative
Member under the Act, and (c) all authority, rights and powers in the management
of the  Company  business to do any and all acts and things  necessary,  proper,
appropriate,  advisable,  incidental or convenient to effectuate the purposes of
this Agreement.  Any action taken by the Administrative  Member on behalf of the
Company,  other than a Major  Decision  as  provided  in  Section  7.3 that both
Members shall have approved in writing,  shall  constitute  the act of and shall
serve to bind the Company.  In dealing with the Administrative  Member acting on
behalf of the Company, no Person shall be required to inquire into the authority
of the Administrative  Member to bind the Company, and such Persons dealing with
the Company shall be entitled to rely conclusively on the power and authority of
the Administrative Member.

     Section 7.2 DUTIES OF ADMINISTRATIVE MEMBER; AGENTS.

          (a) The  Administrative  Member shall cause the affairs of the Company
     to be  conducted in an efficient  and  businesslike  manner and in complete
     compliance with the City Agreement. The Administrative Member shall perform
     its  duties  as a  Administrative  Member  in good  faith,  in a manner  it
     reasonably  believes to be in or not opposed to the best  interests  of the
     Company  and with the care  that an  ordinary  prudent  person in a similar
     position would use under similar  circumstances.  The Administrative Member
     may, by written instrument and at the expense of the Company,  delegate all


                                      -62-
<PAGE>
     or any of its powers,  rights and  obligations  hereunder  and may appoint,
     employ,  contract or otherwise deal with any Person for the  transaction of
     business  of the  Company,  which  Person  may,  under  supervision  of the
     Administrative  Member, perform any acts or services for the Company as the
     Administrative Member may approve.

          (b) Each  year the  Administrative  Member  shall  prepare  an  Annual
     Operating  Budget,  Annual  Leasing Plan and Annual  Capital Plan  ("Annual
     Plans")  for  approval  by  the  Members,   which  approval  shall  not  be
     unnecessarily  conditioned  or  delayed.  A Member  shall be deemed to have
     approved  such  Annual  Plans  unless  such  Member  shall have  stated its
     objections to same within 45 days after receipt of such Annual Plans. Prior
     to approval by the Members of the Annual Plans the  appropriate  provisions
     of the prior  versions of such Annual Plans shall remain in effect with the
     dollar  amounts  increased by the Consumer Price Index ("CPI") for the most
     recently  completed  calendar  year.  The  CPI  shall  be the  CPI-U  index
     published by the U.S. Bureau of Labor Statistics (All Urban Consumers,  All
     Items, All Areas, 1984-86 = 100) or any successor index. The initial Annual
     Plans are attached hereto as Exhibit E.

     Section 7.3 MAJOR DECISIONS.  The Administrative  Member shall not have the
authority to take any of the following  actions on behalf of the Company without
the prior written  approval of all Members  without  regard to their  Percentage
Interest:

               (i) change the  purposes  of the  Company as set forth in Section
          2.3, or take any action which is inconsistent with such purposes;

               (ii)  obligate  the  Company as  guarantor,  endorser,  surety or
          accommodation party except as provided in the Loan Agreements;

               (iii) except as provided in the Annual  Plans,  cause the Company
          to incur or refinance any indebtedness;

               (iv) assign, transfer,  pledge,  compromise or release any claims
          of or debts in amounts in excess of $200,000 due the Company except on
          payment in full;

               (v) enter into any contract or agreement  between the Company and
          any  Affiliate of the  Administrative  Member which is not on terms at
          least as favorable to the Company as an arms-length transaction;

               (vi)  except as  provided  in Article  IX,  admit any Person as a
          Member to the Company;

               (vii)  allow the Company to enter into any lease (A) in which the
          lessee's  two year  average net worth is not equal to or greater  than
          the amount which is ten (10) times the estimated total rent obligation
          of the prospective  lessee; (B) in which lessee shall not have been in
          business  at  least  five  (5)  years;  (C) in  which  the area of the
          premises to be leased is in excess of one full floor of the  Property;
          or (D) which  contains terms which  materially  differ from the Annual
          Leasing Plan then in effect;

               (viii) initiate any renovation,  alteration or  redevelopment  of
          the  Property  or any  single  capital  expenditure  item in excess of
          $200,000, except as included in the Annual Capital Plan then in effect
          or to address a need of the Company in an emergency;

               (ix)  enter into any  property  management  or leasing  agreement
          (except commission agreements with an unrelated third party brokers in
          connection with leasing in the ordinary course of business);


                                      -63-
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               (x) determine not to enforce any material lease of the Property;

               (xi) list the Property for sale;

               (xii) make a direct or  indirect  transfer  of an Interest in the
          Company except as otherwise permitted in this Agreement;

               (xiii) file for bankruptcy; or

               (xiv) sell the Property.

     Section 7.4  NON-DELEGATION.  Each Member shall indemnify and hold harmless
the other Member and the Company  against any and all claims that my be asserted
against  the  other  Member  or  the  Company  arising  out  of or  relating  to
unauthorized  actions  that such  Member or any  Affiliate  of such  Member  has
purported to take on behalf of the other Member or the Company,  or both. Except
as expressly set forth in Article VII of this Agreement or specifically approved
by the Members,  neither any Member nor the Administrative Member shall have the
unilateral authority to act for or to bind the Company.

                                  ARTICLE VIII

                                 OTHER BUSINESS

     Section 8.1 PRIME.  Nothing  herein  shall limit or restrict the ability of
any  Member to engage in any  business  activity,  whether  or not  directly  or
indirectly  competitive with the business of the Company, or whether or not such
activity may be an  opportunity  of a nature that the Company  would  undertake.
Notwithstanding  the  foregoing,  and  except as  provided  in this  Article  in
connection  with  Permitted  Activities  (as  defined  hereinafter),  Prime,  an
Affiliate  or the  property  manager  shall  not have any  discussions  with the
following  three (3) tenants ( the "3 Tenants") of the  Property:  (i) Jones Day
Reavis & Pogue, (ii) Everen  Securities,  Inc., and (iii) R.R.  Donnelley & Sons
Company,  about leasing space in any other building in the downtown Chicago loop
controlled by Prime (and which Prime or an Affiliate has some direct  ownership)
if such discussions  also involve  relocation of any one or more of such tenants
from the Property.

     The foregoing  restrictions  shall not be construed to prohibit  Prime,  an
Affiliate  or the  property  manager  from  engaging in the  ordinary  course of
business discussions regarding building services,  repairs and maintenance items
and other ordinary  day-to-day tenant inquiries including limited discussions in
response  to a direct  inquiry by or on behalf of such  tenant  regarding  space
needs (so long as OTR receives notice of such  discussions  within ten (10) days
of such discussions) or the following activities  (collectively,  the "Permitted
Activities")   with  any  one  or  more  of  the  3  Tenants  following  written
notification to OTR that such activities  would be taking place: (i) discussions
during the last  thirty  (30) months of the lease term  regarding  space  needs,
including, but not limited to, discussions and negotiations regarding relocation
to other properties,  and entering into lease agreements with such tenant at any
other properties,  (ii) substantive negotiations in response to a direct inquiry
by or on behalf of such tenant regarding space needs,  including discussions and
negotiations regarding relocation  opportunities at any time from one or more of
the 3 Tenants  or their  respective  lease or tenant  representative,  including
entering into lease agreements with such tenant for space at any other property,
(iii)  discussions  regarding  additional  space  needs  (in  addition  to space
required at the Property),  including  discussions  and  negotiations  regarding
opportunities at other properties owned by Prime, or (iv) discussions  regarding
space needs at any other time if Prime,  an Affiliate  or the  property  manager
reasonably  believes in good faith that as a result of such  discussions that it
will have lease  opportunities with any tenant or prospective tenants of similar
credit  worthiness  which will not  materially  reduce  the market  value of the
Property based on then current market conditions.

                                      -64-
<PAGE>
     Section 8.2 OTR.  Nothing herein shall limit or restrict the ability of any
Member to engage in any business activity, whether or not directly or indirectly
competitive  with the business of the Company,  or whether or not such  activity
may  be  an  opportunity   of  a  nature  that  the  Company  would   undertake.
Notwithstanding  the  foregoing,  and  except as  provided  in this  Article  in
connection with Permitted  Activities,  OTR shall not have any discussions  with
the 3 Tenants about leasing space in any other building in the downtown  Chicago
loop controlled by OTR (and which OTR or an Affiliate has some direct ownership)
if such discussions  also involve  relocation of any one or more of such tenants
from the Property.

     The  foregoing  restrictions  shall not be  construed  to prohibit OTR from
engaging in the  ordinary  course of  business  discussions  regarding  building
services,  repairs and maintenance  items and other ordinary  day-to-day  tenant
inquiries including limited discussions in response to a direct inquiry by or on
behalf of such tenant regarding space needs (so long as Prime receives notice of
such  discussions  within ten (10) days of such  discussions)  or the  Permitted
Activities with any one or more of the 3 Tenants following written  notification
to Prime that such activities would be taking place.

                                   ARTICLE IX

                                 TRANSFERABILITY

     Section 9.1 GENERAL.  Except as otherwise  provided in this  Agreement,  no
Member may sell,  assign,  exchange  (collectively  "sell" or "sale") all or any
part of its  Membership  Interest to a transferee (a  "Transferee")  without the
prior  written  consent of the other  Member  which may be  withheld in its sole
discretion.  Notwithstanding the foregoing,  no consent shall be required if the
Transferee is an Affiliate of the Transferor.  Transferor  shall not be released
from its obligations in the event of such sale. Each Member hereby  acknowledges
the reasonableness of the restrictions on sale of such interests imposed by this
Agreement  (including this Article IX) in view of the Company's purposes and the
relationship  of the Members.  Accordingly,  the  restrictions on sale contained
herein shall be  specifically  enforceable.  If any Member  pledges or otherwise
encumbers its Membership Interest as security for repayment of a liability,  any
such pledge or hypothecation shall be made pursuant to a pledge or hypothecation
agreement  that  requires  the  pledgee or secured  party to be bound by all the
terms and conditions of this Article IX. The restrictions on transfer  contained
in  this  Article  IX  are   intended  to  comply  (and  shall  be   interpreted
consistently)  with the restrictions on transfer set forth in the ?18-702 of the
Act.

     Section 9.2  TRANSFEREE  NOT MEMBER IN ABSENCE OF CONSENT.  Notwithstanding
anything contained herein to the contrary,  a Transferring  Member may only sell
its Membership  Interest to a Transferee which is not a Member immediately prior
to the sale  upon:  (i) the  reasonable  determination  of legal  counsel to the
Company  that  the sale is  exempt  from the  registration  requirements  of the
Securities  Act of 1933  and  applicable  state  securities  laws  and  does not
jeopardize  any  exemption  from such laws on which the Company  had  previously
relied in selling  Membership  Interests;  (ii) the reasonable  determination of
legal counsel to the Company that the sale will not adversely  affect the status
of the  Company  for tax  purposes  or the  status of the  Company  as a limited
liability  company under applicable laws; (iii) the reasonable  determination of
counsel  to each  Member  that  the  sale  will  not  cause a  violation  of any
applicable  law or  regulation  binding upon it; (iv) the  Transferee's  written
agreement to be bound by the terms of this Agreement;  and (v) the  Transferee's
agreement to pay all reasonable  expenses of the Company in connection  with the
transfer.  Any attempted or purported sale in contravention of the terms of this
Operating  Agreement shall be voidable at the option of the Company. No transfer
of a  Member's  Interest  shall be  effective  unless and until  written  notice
(including the name and address of the proposed transferee or donee and the date
of such  transfer)  has been  provided to the  Company and the  non-transferring
Member.
                                      -65-
<PAGE>
     Section 9.3 SALE OF MEMBERSHIP  INTEREST.  At any time after  September 30,
2001 (the  period  prior to such date  hereinafter  referred to as the "Lock Out
Period")  either OTR or Prime (the  "Initiating  Member")  may, by notice to the
other,  require  the other  (the  "Responding  Member")  to elect  either (x) to
purchase all (but not less than all) of the Initiating  Member's Interest in the
Company,  or (y) to sell to the Initiating Member all (but not less than all) of
the Responding  Member's Interest in the Company,  in either case at a price and
terms set forth in such  notice.  Upon receipt of such  notice,  the  Responding
Member  receiving  such notice shall  notify the  Initiating  Member  within one
hundred twenty (120) days whether the Responding Member elects so to purchase or
sell.  If the  Responding  Member does not notify the  Initiating  Member of the
Responding Member's election in such 120-day period, the Responding Member shall
be deemed to have elected to sell. The purchasing  party shall pay for the other
Member's  Interest in cash. The closing will be held at the principal offices of
the Company within sixty (60) days after the Responding  Member has notified (or
been deemed to have notified) the Initiating  Member of the Responding  Member's
election.  The purchasing  Member agrees to cooperate with the selling Member to
have the sale  structured as a like kind exchange under Section 1031 of the Code
if the selling Member so requests.

     Section 9.4 CHANGE OF CONTROL.  If Prime Group enters into an agreement for
merger,  consolidation,  reorganization  or  similar  transaction  with  another
entity,  and if  immediately  following  the  effective  date  of  such  merger,
consolidation or similar transaction ("Transaction Effective Date") the majority
of the Board of  Directors of Prime is comprised of persons who were not members
of the Board of  Directors  or employees  of Prime  immediately  preceding  such
Transaction  Effective  Date, then the Lock Out Period shall expire on the 180th
day following the Transaction Effective Date.

                                    ARTICLE X

                           DISSOLUTION AND TERMINATION

     Section 10.1 DISSOLUTION. The Company shall continue until dissolved by any
of the following events:

          (a) the unanimous written consent of the Members;

          (b) the bankruptcy or dissolution of a Member or the occurrence of any
     other event that  terminates  the  continued  membership of a Member in the
     Company; or

          (c) any other event causing dissolution of a limited liability company
     under the Act.

     Section  10.2  CONTINUANCE  OF  COMPANY.   Notwithstanding   the  foregoing
provisions of Section 10.1, upon the occurrence of an event described in Section
10.1(b) with respect to a Member (the  "Withdrawing  Member"),  the other Member
shall have the right to continue the business of the Company.  Such right can be
exercised  only if the Member  that is not the  Withdrawing  Member  consents in
writing,  within 90 days after the occurrence of the event  described in Section
10.1(b),  to continue the business of the Company.  If the right to continue the
business of the Company is exercised,  the Withdrawing Member shall no longer be
a Member of the Company but shall  continue to be entitled to the  distributions
such Member would  otherwise be entitled to receive if it was not a  Withdrawing
Member.  If the Member  that is not the  Withdrawing  Member does not consent to
continue the  Company,  the right of the Members to continue the business of the
Company shall expire, the Administrative Member shall file a statement of intent
to dissolve,  and the Company's affairs shall be wound up by the  Administrative
Member.




                                      -66-
<PAGE>
     Section 10.3 TERMINATION.  After an event occurs that requires a winding up
as described in this Article X, the Company will continue in existence until the
winding up and  liquidation  of its  business as  described in this Article X is
completed. When the winding up is completed, the Company will terminate.

     Section 10.4 ACTIVITIES  DURING WIND UP. After the date as of which winding
up is required,  the Company  shall not enter into any contract or undertake any
business  not then subject to contract or which is not related to the winding up
of the  Company.  Upon  winding  up,  a proper  accounting  shall be made of the
Company's assets, liabilities, and operations from the date of the last previous
accounting  to the date as of which  winding up is  required.  The  Profits  and
Losses realized  subsequent to the date as of which winding up is required shall
be allocated in  accordance  with Article V and proper  adjustments  made to the
Capital  Account of each Member.  Profits and Losses realized on the sale of any
Company  asset in the  process of winding up shall be  allocated  as provided in
Article V. Assets not sold will be valued at their fair market value and gain or
loss  allocated  as provided in Article V as if they had been sold at their fair
market value.

     Section 10.5 LIQUIDATION.  As soon as the actions contemplated by preceding
sections of this Article have been  completed,  the cash and other assets of the
Company shall be applied or distributed in the following order of priorities:

          10.5.1 In payment of all liabilities of the Company to creditors other
     the Members.  If any  liability is  contingent,  or uncertain in amount,  a
     reserve equal to the maximum  amount to which the Company could  reasonably
     be  held  liable  will be  established.  Upon  the  satisfaction  or  other
     discharge  of such  contingency,  the amount of the reserve not needed,  if
     any, will be distributed in accordance with the balance of this Section;

          10.5.2 To the Members in payment of any amounts  outstanding to any of
     the Members in payment of any loans made by the Members to the Company;

          10.5.3  To OTR  until  the  cumulative  distributions  to OTR  for the
     current and all prior  Company  taxable years  pursuant to Sections  5.2.1,
     5.3.1 and this Section 10.5.3 equals the Priority Return;

          10.5.4  To OTR  until  the  cumulative  distributions  to OTR  for the
     current and all prior Company  taxable years  pursuant to Section 5.3.2 and
     this Section 10.5.4 equals the Preferred Equity; and

          10.5.5 To the Members in accordance with the positive Capital Accounts
     of the Members.

No Member with a negative  balance in its Capital Account shall be liable to the
Company or any other Member for the amount of such negative balance upon winding
up and liquidation.

                                   ARTICLE XI

                                    NO WAIVER

     The failure of either Member to enforce any provision of this  Agreement or
right  granted  hereby  shall not in any way be construed to be a waiver of such
provision or right,  nor in any way affect the validity of this Agreement or any
part  thereof,  or  limit,  prevent,  or  impair  the  right  of  either  Member
subsequently  to enforce such  provisions  or exercise  such right in accordance
with its terms.






                                      -67-
<PAGE>
                                   ARTICLE XII

                              NO RIGHT TO PARTITION

     The Members  expressly  waive and  release any right to have the  Company's
assets  partitioned or sold for the period during which the Company shall remain
in existence.
                                  ARTICLE XIII

                                     GENERAL

     Section 13.1  ENTIRETY OF  AGREEMENT.  This  Agreement,  together  with the
Contribution  Agreement and Property Management and Leasing Agreement,  reflects
the whole and entire  agreement  among the Members  with  respect to the subject
matter herein and supersedes all previous  agreements and  understandings  among
the Members, and may be amended,  restated,  or supplemented only by the written
agreement of all Members.

     Section  13.2  NOTICES.  Unless  otherwise  specifically  provided  in this
Agreement,  any written  notice or other  communication  given  pursuant to this
Agreement shall be  sufficiently  delivered if delivered  personally  (including
delivery  by a  nationally  recognized  express  delivery  service) or mailed by
registered or certified mail:

          (a) to each of the  Members at the  address set forth below or at such
     other address as may be designated from time to time by a Member by written
     notice to the other Member and to the Company:

                  If to Prime:

                  Prime Group Realty, L.P.
                  77 Wacker Drive, Suite 3900
                  Chicago, IL  60601
                  Attention: President

                  With a copy to:

                  Prime Group Realty, L.P.
                  77 Wacker Drive, Suite 3900
                  Chicago, IL  60601
                  Attention:  General Counsel

                  With a copy to:

                  Winston & Strawn
                  35 W. Wacker Drive
                  Chicago, Il 60601
                  Attention:  William J. Ralph

                  If to OTR:

                  The State Teachers Retirement
                    System of Ohio
                  275 East Broad Street
                  Columbus, OH  43215-3771
                  Attention:  Director, Real Estate Assets

                  With a copy to:

                  Taft, Stettinius & Hollister, L.L.P.
                  1800 Firstar Tower
                  425 Walnut Street
                  Cincinnati, Ohio 45202-3957
                  Attention: Edward D. Diller
                                      -68-
<PAGE>
          (b) to the  Company  at the  principal  office of the  Company or such
     other address as may be designated  from time to time by written  notice to
     each of the Members.

     A notice (i) sent via hand delivery shall be deemed  delivered upon receipt
or  refusal  of  delivery  or (ii) sent via a  nationally  recognized  overnight
courier  shall be deemed  delivered  one  business  day after  deposit with such
courier.

     Any Member may request  that copies of notices be given to an  Affiliate of
the Member at the address  designated  by such  Member by written  notice to the
other Member and to the  Company;  provided,  however,  that any failure to give
such notice  shall not affect the  validity of any notice given to the Member or
to the Company in accordance  with this Section 13.2. Each of the Members agrees
to give such designated notice to any designated Affiliate.

     Section 13.3 FURTHER ASSURANCES.  Each Member agrees to execute and deliver
all such other and  additional  instruments  and  documents and to do such other
acts and things as may be  reasonably  necessary  more fully to  effectuate  the
Company and carry on the Company business in accordance with this Agreement.

     Section 13.4  APPLICABLE LAW AND CHOICE OF FORUM.  This Agreement  shall be
governed  by and  interpreted  in  accordance  with  the  laws of the  State  of
Delaware, except that any conflict of laws rule of such jurisdiction which would
require reference to the laws of some other jurisdiction shall be disregarded.

     Section 13.5 COUNTERPARTS. This Agreement may be executed in
counterparts,  each of  which  shall be  deemed  an  original,  but all of which
together shall constitute but one and the same instrument.

     Section 13.6  HEADINGS.  The headings  contained in this  Agreement are for
reference  purposes only and shall not affect the meaning or  interpretation  of
this Agreement.

     Section 13.7 WAIVER. No waiver or default by either Member in the
performance of any provision,  condition,  or requirement herein shall be deemed
to be a waiver of, or in any manner  release the other Member from,  performance
of any other provision,  condition, or requirement herein, nor shall such waiver
be deemed to be a waiver  of, or in any manner a release  of,  the other  Member
from future performance of the same provision,  condition,  or requirement.  Any
delay or omission of either  Member to exercise  any right  hereunder  shall not
impair the  exercise of any such right,  or any  similar  right,  accruing to it
thereafter.  The failure of either Member to perform its  obligations  hereunder
shall not release the other Member from the performance of such obligation.

     Section 13.8  PRONOUNS AND PLURALS.  Whenever the context may require,  any
pronoun  used in this  Agreement  shall  include  the  corresponding  masculine,
feminine, or neuter forms, and the singular form of nouns,  pronouns,  and verbs
shall include the plural and vice versa.

     Section 13.9 FORCE MAJEURE. If either Member is rendered unable,  wholly or
in part, by force  majeure to carry out its  obligations  under this  Agreement,
other  than the  obligation  to make money  payments,  the  obligations  of such
Member,  so far as they are affected by such force  majeure,  shall be suspended
during the continuance of such force majeure.  The term "force majeure," as used
herein,  shall  mean  an  act of  God,  strike,  lockout,  or  other  industrial
disturbance,  act of public enemy, war, blockade, public riot, lightning,  fire,
storm, flood, explosion, governmental restraint,  unavailability of equipment or
supplies, and any other cause, whether of the kind specifically enumerated above
or otherwise,  which is not  reasonably  within the control of such Member.  The
requirement that any force majeure shall not be reasonably within the control of
such Member shall not require  settlement of strikes,  lockouts,  or other labor
difficulty  by such Member,  contrary to its wishes;  and all such  difficulties
shall be handled entirely at the discretion of such Member.
                                      -69-
<PAGE>
     Section 13.10 SECTION NUMBERS.  Unless otherwise  indicated,  references to
Section numbers are to Sections of this Agreement.

     Section 13.11 NOTICE OF LITIGATION. Either Member that becomes aware of any
litigation  pending  against the Company shall give timely notice of such to the
Company  and the  other  Member.  Additionally,  any  Member  against  which any
litigation  is filed in its capacity as a Member shall give the other Member and
the Company timely notice of such litigation.

     Section 13.12 SEVERABILITY.  Any provision of this Agreement  prohibited by
applicable  law shall be invalid to the extent of such  prohibition  and severed
from this  Agreement  unless it is determined  by the Members by unanimous  vote
that such  prohibition  invalidates the purpose or intent of this Agreement,  in
which case the Company shall be dissolved and its business and affairs wound up,
liquidated, and terminated.

     Section  13.13 NO DRAFTING  PRESUMPTION.  No  presumption  shall operate in
favor of or against any Party hereto as a result of any responsibility  that any
Party may have had for drafting this Agreement.

     Section 13.14 THIRD-PARTY BENEFICIARIES.  The representations,  warranties,
covenants,  and  obligations  of the  Parties  hereto  are made for the  express
benefit of the  Parties  hereto,  and Persons  that are not express  signatories
hereto are not intended to have, nor shall have, the benefit of, or any right to
seek enforcement or recovery under, any of such covenants or obligations.

     Section  13.15  REMEDIES.  Except as otherwise  expressly  provided in this
Agreement,  all rights and remedies  under this  Agreement are cumulative and in
addition to other rights or remedies under this Agreement or any applicable law.

     Section 13.16 DESIGNATION OF FORUM AND CONSENT TO JURISDICTION. The parties
hereto (a) designate the United States District Court for the Northern  District
of Illinois as the forum where all matters  pertaining to this  Agreement may be
adjudicated,  and (b) by the  foregoing  designation,  consent to the  exclusive
jurisdiction and venue of such court for the purpose of adjudicating all matters
pertaining to this Agreement

     Section 13.17 WAIVER OF JURY TRIAL. As a specifically  bargained inducement
for each other party to enter into this  Agreement,  each of the parties  hereto
waives any right it may have to have a jury participate in resolving any dispute
arising out of or related to this Agreement,  the Contribution Agreement and the
Property Management and Leasing Agreement.  Instead,  any such disputes resolved
in court shall be resolved in a bench trial without a jury.

     Section 13.18 BINDING  AGREEMENT.  This Agreement shall be binding upon all
parties hereto,  their successors and assigns, and shall inure to the benefit of
the parties hereto, their successors and assigns.

     Section 13.19 EXCULPATION.

          (a) OTR.  This  Agreement is executed by certain  general  partners of
     OTR,  not  individually,  but solely on behalf  of,  and as the  authorized
     nominee  and  agent  for  The  State  Teachers  Retirement  Board  of  Ohio
     ("STRBO"), and in consideration for entering into this Agreement, Prime and
     77WWLP  hereby  waive any  rights to bring a cause of  action  against  the
     individuals executing this Agreement on behalf of OTR (except for any cause
     of action based upon lack of authority or fraud),  and all persons  dealing
     with OTR must look  solely to  STRBO's  assets for the  enforcement  of any
     claim against OTR, and the obligations  hereunder are not binding upon, nor
     shall  resort  be had  to  the  private  property  of any of the  trustees,
     officers, directors, employees or agents of STRBO.



                                      -70-
<PAGE>
          (b) Prime.  This  Agreement  is executed by certain  individuals,  not
     individually, but solely on behalf of, and as the authorized representative
     for 77 WWLP and its general partners. OTR hereby waives any rights to bring
     a cause of action  against the  individuals  executing  this  Agreement  on
     behalf  of 77 WWLP  (except  for any  cause of  action  based  upon lack of
     authority or fraud),  and all persons dealing with 77 WWLP must look solely
     to the assets of 77 WWLP and its general partner and such general partner's
     general  partner for the  enforcement of any claim against 77 WWLP, and the
     obligations  hereunder are not binding upon, nor shall resort be had to the
     private property of any of the trustees, officers, directors,  employees or
     agents  of (i) 77 WWLP  or  (ii)  the  general  partner  of 77 WWLP or such
     general partner's general partners.

     Section 13.20 LIKE KIND EXCHANGE.

          (a) The Company and OTR agree to cooperate  with 77WWLP,  as described
     in subsection (b) below,  to accommodate  the desire of 77WWLP to treat the
     Capital  Contribution  and  distribution to 77WWLP  contemplated by Section
     4.2.1(a) and 5.1 as part of a tax deferred exchange by 77WWLP under Section
     1031 of the Code;  however,  OTR and 77WWLP  acknowledge and agree that the
     Company  and OTR shall  have no  responsibility  for the tax  treatment  to
     77WWLP and all cost, expenses and liabilities will be borne by 77WWLP.

          (b) In  order to  accommodate  77WWLP,  the  Company  agrees  that (i)
     consistent  with  Section  13.20(a)  hereof,  it  shall  make  payment,  as
     requested  by 77WWLP,  to the person or persons  designed by 77WWLP,  which
     person will be intended to be a "qualified escrow" or "qualified trust" for
     purposes  of  Section  1.1031(k)-1(g)(3)  of the  Regulations,  and (ii) as
     requested by 77WWLP,  the Company will  consent to the  assignment  of this
     Agreement on or after the date hereof to a person,  who is intended to be a
     "qualified  intermediary" for purposes of Section  1.1031(k)-1(g)(3) of the
     Regulations.

     Section  13.21  PERFORMANCE/HOLIDAYS.  Whenever  under  the  terms  of this
Agreement  the time for  performance  falls  upon a  Saturday,  Sunday  or legal
holiday, such time for performance shall be extended to the next business day.

     In WITNESS  WHEREOF,  the Members have caused this Agreement to be executed
by their respective duly authorized officers as of the date first above written.

                                   77 WEST WACKER LIMITED PARTNERSHIP

                                   By: Prime Group Realty, L.P., its
                                       general partner

                                   By: Prime Group Realty Trust, its
                                       managing partner

                                   By: /s/ Jeffrey A. Patterson
                                       -----------------------------------------

                                   PRIME GROUP REALTY, L.P.

                                   By: Prime Group Realty Trust, its managing
                                       partner

                                   By: /s/ Jeffrey A. Patterson
                                       -----------------------------------------

                                   OTR

                                   By: /s/ Stephen A. Mitchell
                                       -----------------------------------------
                                       General Partner
                                      -71-
<PAGE>
                                   Exhibit "A"

                                 LOAN AGREEMENTS


                             Intentionally Deleted


























































                                      -72-
<PAGE>
                                   Exhibit "B"

                       DETERMINATION OF FAIR MARKET VALUE

(i) "FAIR MARKET  VALUE"  shall mean the purchase  price that a willing and able
buyer  would  pay,  and a  willing  seller  would  accept,  in an  arm's  length
transaction,  for the Property, all as determined as of the date of the election
by the Contributing Member in Section 4.3.

(ii)  Within  thirty  (30)  days  after  Non-Contributing  Member  receives  the
Contributing  Member's  notice of  election  to  decrease  the  Non-Contributing
Member's   Percentage   Interest,    the   Contributing   Member   will   Notify
Non-Contributing  Member in writing of its estimate of the Fair Market Value. If
Non-Contributing  Member  does not object to such  estimate  in  writing  within
thirty (30) days after  receiving  the  Contributing  Member's  estimate of Fair
Market  Value,  such  estimate  shall be deemed to be the Fair Market  Value for
purposes  of this  provision.  If  Non-Contributing  Member  does object to such
estimate in writing  within thirty (30) days after  receiving  the  Contributing
Member's estimate of Fair Market Value, the parties will negotiate in good faith
to agree on Fair Market  Value.  If the parties fail to agree on the Fair Market
Value within thirty (30) days after the date that  Contributing  Member receives
Non-Contributing  Member's notice of objection, the determination of Fair Market
Value will be  determined  by appraisal in  accordance  with the same  appraisal
procedure outlined in this Exhibit "B".

(iii) If the Fair Market Value is to be determined by appraisal, within ten (10)
days  after the  expiration  of the 30-day  negotiation  period  referred  to in
paragraph (ii) above,  Contributing Member and Non-Contributing Member will each
appoint an  independent  appraiser who is a member of the American  Institute of
Real Estate  Appraisers  ("MAI") and who has had a minimum of ten (10) years' of
experience   in  valuation  of  high  rise  office   buildings  in  the  Chicago
marketplace,  and shall deliver  written notice of the name of such appraiser to
the other party. If only one of Contributing Member or  Non-Contributing  Member
so delivers  such  written  notice of the name of such an  appraiser,  then such
appraiser will be deemed to be a mutually  acceptable  appraiser who will act as
the  third  appraiser  described  below.  If  neither  Contributing  Member  nor
Non-Contributing  Member  so  delivers  such  written  notice  of the name of an
appraiser  to the other party,  then either  party may petition the  appropriate
federal  court  sitting in  Illinois to appoint  the third  appraiser  described
below.  If two appraisers  are so named by the parties,  then the two appraisers
will meet  within 15 days  after the date on which the  notice of the  second of
such appraisers is so given,  and such appraisers will select a third appraiser,
who also meets the qualification  requirements of the first two appraisers,  and
who has not acted previously in any capacity for either  Non-Contributing Member
or  Contributing  Member,  and will deliver  written  notice of the name of such
third appraiser to the parties within such 15 day period. If such two appraisers
have not so delivered  written notice of such third appraiser within such 15 day
period,  then either party may petition the appropriate federal court sitting in
Illinois to appoint such third appraiser.

(iv)  Within  forty-five  (45) days after such  third  appraiser  is so named or
appointed  (including  a sole  appraiser  deemed  to be the third  appraiser  as
provided  above),  Non-Contributing  Member and  Contributing  Member  will each
deliver to the third appraiser Non-Contributing Member's and Contributing Member
respective  estimates of the Fair Market Value. Such estimates will be delivered
to such third  appraiser in sealed  packages,  and such package may contain such
supporting data as the party delivering such estimate desires. If such estimates
are within  one and  one-half  percent  (1 1/2%) of each other then Fair  Market
Value  shall  be  equal  to the  average  of the two  estimates.  If only one of
Non-Contributing  Member or Contributing Member so delivers such estimate to the
third appraiser  within such time, then the estimate so delivered will be deemed
to be the Fair Market Value. If neither Non-Contributing Member nor Contributing


                                      -73-
<PAGE>
Member deliver such estimate to the third  appraiser  within such time, then the
estimate first  delivered to the third appraise  thereafter will be deemed to be
the Fair  Market  Value.  Within  thirty  (30) days after the  delivery  of such
estimates  by  Non-Contributing   Member  and  Contributing  Member,  the  third
appraiser will make a determination as to which of the Non-Contributing Member's
or  Contributing  Member's  estimate of Fair Market Value is closest to the Fair
Market Value.  The third appraiser may not substitute any other estimate of Fair
Market Value,  may not average the  estimates of Fair Market Value  estimated by
Non-Contributing Member and Contributing Member, and may not alter in any manner
the  estimate of Fair  Market  Value made by either  Non-Contributing  Member or
Contributing  Member  (it is the  parties'  intent  that  appraisal  under  this
paragraph  will be a so  called  "baseball"  appraisal  under  which  the  third
appraiser  must select  either the  Non-Contributing  Member's  estimate of Fair
Market Value or  Contributing  Member's  estimate of Fair Market Value,  as such
estimates are submitted to the third appraiser by the parties). Non-Contributing
Member and  Contributing  Member will pay the fee of the appraiser each selected
and each shall pay 50% of the fee of the third appraiser.















































                                      -74-
<PAGE>
                                   EXHIBIT E
                                   ---------


             Management Office Furniture & Equipment Furniture List

                                 77 West Wacker
                                    Chicago


                             Intentionally Deleted





















































                                      -75-
<PAGE>
                                  APPENDIX 2.2
                                  ------------

                                Escrow Agreement

                         CHICAGO TITLE AND TRUST COMPANY


         STRICT JOINT ORDER #1 ESCROW TRUST INSTRUCTIONS (EARNEST MONEY)
         ---------------------------------------------------------------


ESCROW TRUST NO.:  D2 099064809                           DATE:  August __, 1999

To:  Chicago Title and Trust Company, Escrow Trustee:


Customer Identifications

Seller:  77 West Wacker Limited Partnership, an Illinois limited partnership

Purchaser:  OTR,  an Ohio  general  partnership,  acting  on behalf of The State
            Teachers Retirement System of Ohio

Property Address:  77 W. Wacker Drive, Chicago, IL

Project Reference:

Proposed Disbursement Date:  September 30, 1999


Deposits:
- ---------

1.   The sum of $500,000 by OTR representing EARNEST MONEY


Delivery of Deposits:
- ---------------------

The above-referenced  escrow trust deposits  ("deposits") are deposited with the
escrow  trustee to be  delivered by it only upon the receipt of a joint order of
the undersigned or their respective legal representatives or assigns.

In no case shall the  above-mentioned  deposits be  surrendered  except upon the
receipt  of an order  signed  by the  parties  hereto,  their  respective  legal
representatives or assigns, or in obedience to the court order described below.

Billing Instructions:
- ---------------------

Escrow  trust fee will be billed as follows:  one-half to Seller and one-half to
Purchaser.

An annual maintenance fee, as determined by the then current rate schedule, will
commence the Effective Date.

PLEASE  NOTE:   The  escrow  trust  fee  for  these  joint  order  escrow  trust
instructions  is due and payable within 30 days from the projected  disbursement
date (which may be amended by joint written direction of the parties hereto). In
the event no projected disbursement date is ascertainable, said escrow trust fee
is to be billed at  acceptance  and is due and  payable  within 30 days from the


                                      -76-
<PAGE>
billing  date.  Chicago Title and Trust  Company,  at its sole  discretion,  may
reduce or waive the escrow trust fee for these joint order  escrow  instructions
in the event the funds on deposit  herein are  transferred  to or  disbursed  in
connection with sale escrow trust instructions or an agency closing  transaction
established at Chicago Title.

Investment:
- -----------

Deposits  made pursuant to these  instructions  may be invested on behalf of any
party or parties hereto;  provided that any direction to escrow trustee for such
investment  shall be expressed in writing and contain the consent of all parties
to this  escrow,  and also  provided  that  escrow  trustee is in receipt of the
taxpayer's  identification  number  and  investment  forms as  required.  Escrow
trustee will, upon request,  furnish  information  concerning its procedures and
fee schedules for investment.

In the event the  escrow  trustee is  requested  to invest  deposits  hereunder,
Chicago  Title and Trust Company is not to be held  responsible  for any loss of
principal  or  interest  which  may  be  incurred  as a  result  of  making  the
investments or redeeming said  investment for the purposes of these escrow trust
instructions.

Direction Not to Invest/Right to Commingle:
- -------------------------------------------

Except as to deposits of funds for which  escrow  trustee has  received  express
written  direction  concerning  investment or other  handling the parties hereto
direct the escrow trustee NOT to invest any funds deposited by the parties under
the terms of this escrow and waive any rights which they may have under  Section
2-8 of the Corporate  Fiduciary  Act (205 ILCS  620/2-8) to receive  interest on
funds deposited  hereunder.  In the absence of an authorized direction to invest
funds,  the parties  hereto agree that the escrow trustee shall be under no duty
to invest or  reinvest  any such  funds at any time held by it  hereunder;  and,
further,  that escrow  trustee may commingle  such funds with other  deposits or
with its own funds in the manner provided for the  administration of funds under
said  Section  2-8 and may use any part or all of such funds for its own benefit
without  obligation to any party for interest or earnings  derived  thereby,  if
any.  Provided,   however,   nothing  herein  shall  diminish  escrow  trustee's
obligation to apply the full amount of such funds in  accordance  with the terms
of these escrow instructions.

Compliance With Court Order:
- ----------------------------

The undersigned authorize and direct the escrow trustee to disregard any and all
notices,  warnings  or  demands  given or made by the  undersigned  (other  than
jointly) or by any other person.  The said undersigned also hereby authorize and
direct the escrow  trustee to accept,  comply with,  and obey any and all writs,
orders,  judgments  or  decrees  entered  or issued by any court with or without
jurisdiction;  and in case the said escrow  trustee  obeys or complies  with any
such writ, order, judgment or decree of any court, it shall not be liable to any
of the  parties  hereto or any  other  person,  by  reason  of such  compliance,
notwithstanding  any such writ,  order,  judgment  or decree be entered  without
jurisdiction  or be  subsequently  reversed,  modified,  annulled,  set aside or
vacated.  In case the escrow  trustee is made a party  defendant  to any suit or
proceedings regarding this escrow trust, the undersigned,  for themselves, their
heirs, personal representatives, successors, and assigns, jointly and severally,
agree to pay to said escrow trustee, upon written demand, all costs,  attorney's
fees, and expenses incurred with respect thereto.  The escrow trustee shall have
a lien on the deposit(s)  herein for any and all such costs,  fees and expenses.
If said costs,  fees and expenses are not paid,  then the escrow  trustee  shall
have the right to reimburse itself out of the said deposit(s).

                                      -77-
<PAGE>
Execution:
- ----------

These escrow trust  instructions  are governed by and are to be construed  under
the laws of the state of Illinois. The escrow trust instructions,  amendments or
supplemental instructions hereto, may be executed in counterparts, each of which
shall be deemed an original and all such counterparts  together shall constitute
one and the same instrument.

For Seller:                                 For Purchaser:

Name:    WINSTON & STRAWN                   Name:  TAFT, STETTINIUS & HOLLISTER
                                                   LLP

By:      WILLIAM J. RALPH                   By:    EDWARD D. DILLER

Address: 35 W. Wacker Drive                 Address: 1800 Firstar Tower
         Suite 4200                                  425 Walnut Street
         Chicago, IL  60601                          Cincinnati, OH  45202

Phone:   (312)558-5600                      Phone:   (513) 357-5313
Fax:     (312)558-5700                      Fax:     (513) 381-0205


Signature:___________________               Signature:__________________________

Accepted: Chicago Title and Trust Company, as Escrow Trustee



By:__________________________               Date:_______________________________
    NANCY CASTRO
































                                      -78-
<PAGE>
                                  APPENDIX 2.6
                                  ------------

                                   Loan Terms

     The loan terms shall be the same as set forth in the  attached  letter from
Armin Gemmerich of Westdeutsche Immobilien Bank to The Prime Group dated May 10,
1999,  as modified by letter dated  August 9, 1999 by Louis G.  Conforti to Dirk
Richolt,  and except (i) that no interest rate cap agreement  shall be obtained,
or if one is obtained,  it shall be obtained at no cost to OTR and (ii) interest
shall be  payable at a floating  rate equal to LIBOR plus 125 basis  points,  or
LIBOR  plus 135 basis  points  during  such  period as the ratio of  outstanding
principal balance of the Debt to the value of the Property exceeds 65%.



















































                                      -79-
<PAGE>
<TABLE>
                                 APPENDIX 2.7(1)
                                 ---------------

                     PROPOSED DISTRIBUTION -- 77 WEST WACKER
<CAPTION>

- --------------  ------------  ------------  ------------  ------------  ------------  ------------
   Company        Primary      Secondary        Share       Tertiary        Share         Total
- --------------  ------------  ------------  ------------  ------------  ------------  ------------
<S>             <C>           <C>           <C>           <C>           <C>           <C>
CTIC             14,000,000    40,000,000      0.25641     25,000,000      0.22727     79,000,000

Ticor                          20,000,000      0.12821     19,000,000      0.17273     39,000,000

SUTIC                          10,000,000      0.06410     17,000,000      0.15455     27,000,000

CT&T                                                        5,000,000      0.04545      5,000,000

Commonwealth                   24,000,000      0.15385     11,000,000      0.10000     35,000,000

FATCO                          24,000,000      0.15385     11,000,000      0.10000     35,000,000

Old Republic                   15,000,000      0.09615     10,000,000      0.09091     25,000,000

Stewart                        23,000,000      0.14744     12,000,000      0.10909     35,000,000
- --------------  ------------  ------------  ------------  ------------  ------------  ------------
Totals           14,000,000   156,000,000      1.00000    110,000,000      1.00000    280,000,000
- --------------  ------------  ------------  ------------  ------------  ------------  ------------
</TABLE>


































                                      -80-
<PAGE>
                                 APPENDIX 2.7(3)
                                 ---------------

1.   ALTA Statement executed by 77 WWLP.

2.   GAP executed by 77 WWLP.

3.   Affidavit  that to the best of 77 WWLP's  knowledge no known  violations or
     restrictions of record executed by 77 WWLP.

4.   Survey.

5.   Non-Imputation  Affidavit  and Indemnity  Agreement  executed by 77 WWLP re
     Non-Imputation Endorsement.

6.   Personal Undertaking re: Mechanic's Liens executed by Prime.

7.   Property Manager Lien Waiver.

8.   Payoff Letter and to follow Closing:

     (a)  Mortgage Release;

     (b)  UCC Termination.

9.   Ground Lessor Estoppel.

10.  Deed from 77 WWLP to LLC.

11.  77 WWLP Corporate Documents:

     (a)  Partnership Agreement and Amendments;

     (b)  Good Standing Certificate.

12.  LLC Documents:

     (a)  certification  from the Illinois and Delaware  Secretary of State that
          LLC has properly filed its Articles of Organization;

     (b)  a copy of the Articles of  Organization,  together with any amendments
          thereto;

     (c)  a  copy  of  the  Operating  Agreement,  if  any,  together  with  any
          amendments thereto;

     (d)  a list of incumbent  managers or of incumbent members if managers have
          not been appointed; and

     (e)  certification that no event of dissolution has occurred.














                                      -81-
<PAGE>
13.  Transfer Declaration and Water Certificate to be executed by 77 WWLP:

     (a)  For OTR Equity Investment:

          1)   State of Illinois  Green Sheet;
          2)   Cook County; and
          3)   City of Chicago.

Note:  City and County Stamps to be obtained by Title Company.

     (b)  For transfer from 77 WWLP to LLC:

          1)   City of Chicago.

Note: No Water Certificate  required by Title Company because no stamps since no
      consideration
















































                                      -82-
<PAGE>
                                  APPENDIX 3.2

1.   Title Insurance Endorsement
2.   Most current Title Report, including full copies of all exceptions and
     exhibits
3.   Legal Description
4.   Most recent "As Built" survey showing  locations of all  improvements,
     easements, parking spaces and lot size
5.   Easements, Covenants, and Restrictions
6.   Plans and Specifications
7.   Soils Report
8.   All existing Environmental Assessments or Impact Report/Certifications
9.   Copies of all Leases, including amendments, and work letters
10.  Building Insurance Certificates (as applicable)
     (a)  Liability
     (b)  Property
     (c)  Boiler and Machinery
     (d)  Flood/Earthquake
     (e)  Rental and Business Interruption
11.  Building Certificate of Occupancy and Final Completion Certificate
12.  Service Contracts
13.  Construction and other warranties (still in effect)
14.  Tax Parcel ID Number
15.  Property Tax Statements for the last two years
16.  Financial Statements of 77 WWLP and the Property for the year 1998
17.  Association  Rules  and  Regulations,  if  applicable,  and  1998  dues  or
     assessment
18.  Leasing Agreement and Property Management Agreement
19.  Files  concerning any litigation  associated  with the Property,  currently
     pending, or active within the last three years (1)
20.  Tenant Correspondence Files (1)
21.  Names and telephone numbers for Owner's contact personnel
22.  Current Rent Roll
23.  Tenant financial information in Owner's possession
24.  As schedule of any tenants currently in default
25.  Fitness center operating agreement and extensions
26.  Lease abstracts
27.  Parking agreement
28.  Collateral agreement summary page
29.  Leasing prospects
30.  Property condition assessment checklist
31.  Standard lease agreement
32.  June 1999 (current) rent billing
33.  Three-year occupancy history
34.  Three year tenant improvement summary
35.  Downtown market studies/reports
36.  Stacking plan
37.  Development cost schedule
38.  1999 operating budget
39.  Monthly income statements - January 1999 - May 1999 (YTD)
40.  Monthly check registers - January 1999 - May 1999
41.  Monthly bank statements - January 1999 - May 1999
42.  1998 CAM pool and expenses pool reconciliations
43.  June 1999 (current) aged receivables report
44.  Summary of Security Deposits
45.  Wacker Drive improvement memorandum

Notes: Items marked (1) need not be physically delivered to OTR. OTR may inspect
and copy such items upon request.

To the  extent  that an item  does not  exist,  77 WWLP  will  furnish a written
statement to that effect.


                                      -83-
<PAGE>
                                  APPENDIX 3.4
                                  ------------

                                     [DRAFT]

                               September __, 1999



Mr. Stephen Huber
OTR, Acting on Behalf of
the State Teachers Retirement of Ohio
275 East Broad Street
Columbus, OH  43215-3771

     Re:  Contribution   Agreement  Between  OTR  and  77  West  Wacker  Limited
          Partnership Dated as of September __, 1999; Tax P.I.N. #17-09-422-010

Dear Mr. Huber:

     This  letter  agreement,  when  fully  signed,  modifies  the  Contribution
Agreement  referred to above.  Words with initial  capital  letters used in this
letter agreement without  definition shall have the meanings ascribed to them in
the Contribution  Agreement. 77 WWLP has been advised that a portion of the real
property taxes relating to the two-story  building  located below the Air Rights
Parcel  for the year 1997 are unpaid  and that a tax sale  occurred  on April 2,
1999.

     This letter  confirms the  understanding  of 77 WWLP and OTR concerning the
effect of such tax sale on the rights of the lessee  under the Air Rights  Lease
(the Lease  executed by 77 WWLP and American  National Bank and Trust Company of
Chicago, not personally, but solely as Trustee under Trust No. 66121, as Lessor,
and 77 West Wacker Limited  Partnership dated March 7, 1991 (recorded 3/18/91 as
Document No. 91119739)).

     If at any time,  to the  knowledge of 77 WWLP,  the purchaser of the parcel
identified as Tax Parcel Identification Number 17-09-422-010 (the "Ground") or a
third  party  asserts  that such tax sale has limited or impaired in any fashion
the  obligations  of the lessor under the Air Rights  Lease (or the  correlative
rights of the LLC under the Air Rights Lease),  whether by initiating a lawsuit,
seeking a permit to demolish the support for the Air Rights  Parcel,  using self
help to impair  rights of the LLC under the Air  Rights  Lease,  asserting  such
impairment  in response to a request from the LLC under the Air Rights Lease for
an estoppel certificate,  or otherwise, 77 WWLP shall notify OTR. Within fifteen
(15) days following receipt of such notice, OTR may elect for either 77 WWLP, on
behalf of the LLC, or the LLC itself,  to initiate  (or defend,  as the case may
be) a proceeding (a "Proceeding")  for injunctive and declaratory  relief to the
effect that such tax sale has not impaired the  obligations  of the lessor under
the Air Rights Lease or the  correlative  rights of the LLC under the Air Rights
Lease.

     If OTR elects for 77 WWLP to initiate or defend a  Proceeding  on behalf of
the LLC, 77 WWLP shall on behalf of the LLC  vigorously  assert the LLC's rights
under the Air  Rights  Lease,  its rights of quiet  enjoyment,  its claim for an
easement by  necessity,  and any other legal and  equitable  rights and remedies
that the LLC might have,  except for the right to  compensatory  damages,  as to
which OTR must  consent as  provided  herein in order for 77 WWLP to assert such
right. At OTR's  election,  which shall be made at the same time as the election
whether to initiate or defend a Proceeding,  77 WWLP or the LLC, as the case may
be, shall pay the cost of such  appearance  and  contest,  and be liable for the
liabilities and obligations,  if any, incurred in such Proceeding by the 77 WWLP
or the LLC. In no event in any such Proceeding  shall 77 WWLP seek  compensatory


                                      -84-
<PAGE>
damages  for the  loss of any  rights  of the LLC  under  the Air  Rights  Lease
resulting  from the sale of the  Ground  at such tax  sale,  without  the  prior
written consent of the LLC, exercising its sole and absolute discretion.

     If OTR has  elected  for 77 WWLP (as  opposed  to the LLC) to  initiate  or
defend a Proceeding,  in the event of any recovery by the LLC, the LLC shall pay
the amount of such recovery to 77 WWLP.

     At any time and from time to time,  at the  request of OTR,  the LLC shall,
and 77 WWLP and its successors and assigns,  shall authorize and empower the LLC
to,  request an estoppel  certificate  pursuant to the Air Rights Lease from the
holder of title to the Ground.


                                       Very truly yours,



                                       77 West Wacker Limited Partnership

                                       By Prime Group Realty, L.P., a Delaware
                                       limited partnership, its managing
                                       general partner

                                       By Prime Group Realty Trust, a Maryland
                                       real estate investment trust, its
                                       managing general partner


                                       By:______________________________________
                                       Name:____________________________________
                                       Title:___________________________________


         OTR agrees as provided in the foregoing letter.

                                       OTR


                                       By:______________________________________
                                       Name:____________________________________
                                       Title:___________________________________






















                                      -85-
<PAGE>
                                  APPENDIX 3.7
                                  ------------

                          Tenant Estoppel Certificates


                             Intentionally Deleted

























































                                      -86-
<PAGE>
                                 APPENDIX 5.3(b)
                                 ---------------

                                  Form of Deed

                              SPECIAL WARRANTY DEED


     THIS SPECIAL WARRANTY DEED is made as of the ______ day of  ______________,
1999, by 77 WEST WACKER LIMITED  PARTNERSHIP (the "Grantor"),  having an address
at 77 West Wacker Drive, Suite 3900, Chicago,  Illinois 60601, to 77 WEST WACKER
DRIVE,  L.L.C.  (the  "Grantee"),  the tax  mailing  address of which is 77 West
Wacker Drive, Suite 3900, Chicago, Illinois 60601.

     Grantor,  for and in  consideration  of the sum of Ten Dollars ($10.00) and
other  valuable  consideration,  receipt  of which is hereby  acknowledged,  and
pursuant to proper authority,  hereby Grants,  Bargains,  Sells and Conveys unto
Grantee and its successors and assigns, all right, title and interest of Grantor
in the following described property (collectively the "Property").

     a.   The real  property  described on Exhibit A attached  hereto and made a
          part hereof (the "Land").

     b.   All buildings,  improvements,  fixtures, structures, parking areas and
          landscaping on the Land;

     c.   All  and  singular  the  rights,  benefits,   privileges,   easements,
          tenements,  hereditaments and  appurtenances  thereon or in any matter
          appertaining  to such  Land,  including  any and all  mineral  rights,
          development rights, water rights and the like;

     d.   All  right,  title and  interest  of  Grantor in and to all strips and
          gores and any land lying in the bed of any street, road or alley, open
          or proposed, adjoining such Land;

     e.   The  interest  of the  tenant in a  certain  parcel  (the "Air  Rights
          Parcel")  pertaining to the air space more  particularly  described in
          Parcel [ ] in  Exhibit  A  attached  hereto  and  incorporated  herein
          pursuant  to a certain  Lease dated  March 7, 1991,  between  American
          National  Bank and Trust  Company,  as trustee  under Trust  Agreement
          dated November 26, 1985 and known as Trust Number 66121,  as landlord,
          and  77  West  Wacker  Limited   Partnership,   an  Illinois   limited
          partnership, as Tenant, and recorded as Document Number 9119739 in the
          office of the  Recorder  of Cook  County,  Illinois  (the "Air  Rights
          Lease")  and the  interest of the party  identified  as 77 West Wacker
          Limited  Partnership,  an Illinois limited  partnership,  in a certain
          Parking  Agreement  (the "Parking  Agreement")  dated October 21, 1991
          among  American  National  Bank and  Trust  Company  of  Chicago,  not
          personally  but as trustee under trust  agreement  dated June 18, 1991
          and known as trust  number  52947,  North Loop  Transportation  Center
          Limited  Partnership  and 77 West  Wacker  Limited  Partnership  (such
          rights being  referred to as the  "Appurtenances")  pertaining  to the
          property  more  particularly  described  in  Parcel [ ] in  Exhibit  A
          attached hereto and incorporated herein; and

     (f)  The right, title and interest of the tenant under the Air Rights Lease
          to  buildings,  improvements,   fixtures  and  structures  on,  in  or
          appurtenant to the Air Rights Parcel.

     TO HAVE  AND TO HOLD  the  Property  in fee  simple  unto  Grantee  and its
successors, heirs and assigns, forever.



                                      -87-
<PAGE>
     Grantor has not done or suffered to be done  anything  whereby the Property
is or may be  encumbered  or  charged,  except  for those  matters  set forth in
Exhibit  B   attached   hereto   and   incorporated   herein   (the   "Permitted
Encumbrances").  Grantor  shall  warrant  and defend the  Property  against  all
persons  lawfully  claiming,  or to claim the  Property,  by,  through  or under
Grantor, subject to the Permitted Encumbrances.


                  IN WITNESS WHEREOF, said Grantor has caused this instrument to
be duly executed and delivered by its duly authorized officer, as of the day and
year first above written.


                                       77 WEST WACKER LIMITED PARTNERSHIP

                                       By:  Prime Group Realty, L.P., a Delaware
                                       limited partnership, its general partner

                                       By:  Prime Group Realty Trust, a Maryland
                                       real estate investment trust, its
                                       managing general partner



                                       By:______________________________________
                                       Name:____________________________________
                                       Title:___________________________________



STATE OF ________________ )
                          )  SS:
COUNTY OF _______________ )


     The  foregoing  instrument  was  acknowledged  before me this ______ day of
_________________, 1999 by ___________________, the ___________________ of Prime
Group Realty Trust, a real estate  investment  trust organized under the laws of
Maryland,  managing  general  partner of Prime  Group  Realty,  L.P.,  a limited
partnership  organized  under the laws of Delaware,  general  partner of 77 WEST
WACKER LIMITED  PARTNERSHIP,  a limited partnership  organized under the laws of
Illinois, on behalf of the trust and such partnerships.



                                       _________________________________________
                                       Notary Public

















                                      -88-
<PAGE>
                                    EXHIBIT A
                                    ---------

                                LEGAL DESCRIPTION
                                -----------------



























































                                      -89-
<PAGE>
                                    EXHIBIT B
                                    ---------

    [Insert Schedule B of proforma title policy attached as Appendix 2.7(2)]




























































                                      -90-
<PAGE>
                        STATEMENT BY GRANTOR AND GRANTEE

The grantor or his agent affirms that, to the best of his knowledge, the name of
the grantee shown on the deed or  assignment  of  beneficial  interest in a land
trust is either a natural person, an Illinois corporation or foreign corporation
authorized  to do business or acquire and hold title to real estate in Illinois,
a partnership authorized to do business or acquire and hold title to real estate
in  Illinois,  or other  entity  recognized  as a person  and  authorized  to do
business or acquire and hold title to real estate under the laws of the State of
Illinois.

                                       77 WEST WACKER LIMITED PARTNERSHIP

Dated____________________,    1999     Signature:_______________________________
                                                          Grantor or Agent

Subscribed and sworn to before me by the

said____________________________________

this______________ day of _________ ,

1999

________________________________________
Notary Public


The grantee or his agent affirms and verifies that the name of the grantee shown
on the deed or  assignment  of  beneficial  interest in a land trust is either a
natural person, an Illinois corporation or foreign corporation  authorized to do
business  or acquire and hold title to real estate in  Illinois,  a  partnership
authorized  to do business or acquire and hold title to real estate in Illinois,
or other entity  recognized as a person and authorized to do business or acquire
and hold title to real estate under the laws of the State of Illinois.

                                       77 WEST WACKER DRIVE, L.L.C.

Dated____________________,    1999     Signature:_______________________________
                                                 Grantee or Agent

Subscribed and sworn to before me by the

said____________________________________

this______________ day of __________,

1999

________________________________________
Notary Public

NOTE:Any person who knowingly submits a false statement  concerning the identity
     of a grantee shall be guilty of a Class C misdemeanor for the first offense
     and of a Class A misdemeanor for subsequent offenses.

[Attach to deed or ABI to be recorded in Cook County,  Illinois, if exempt under
provisions of Section 4 of the Illinois Real Estate Transfer Tax Act.]






                                      -91-
<PAGE>
                                 APPENDIX 5.3(c)
                                 ---------------

                       BILL OF SALE AND OMNIBUS ASSIGNMENT

     This Bill of Sale and Omnibus Assignment (this  "Assignment") is made as of
the ______ day of  _______________,  1999 by and between 77 WEST WACKER  LIMITED
PARTNERSHIP  ("Contributor"),  a limited partnership organized under the laws of
Illinois,  and 77  WEST  WACKER  DRIVE,  L.L.C.,  a  limited  liability  company
organized under the laws of Delaware ("LLC").

                                R E C I T A L S:
                                - - - - - - - -

     A. This Bill of Sale and  Omnibus  Assignment  is  executed  and  delivered
pursuant to that certain  Contribution  Agreement (as amended, the "Contribution
Agreement") dated as of August _____, 1999, between Contributor and LLC in which
Contributor  agreed to contribute to LLC the real property described in Schedule
1 attached hereto (the "Land").

     B. All terms with  initial  capital  letters  that are used but not defined
herein shall have the same meanings  ascribed to such terms in the  Contribution
Agreement.

          1.  ASSIGNMENT AND  ASSUMPTION.  For good and valuable  consideration,
     Contributor hereby sells, assigns,  conveys and contributes to LLC, and LLC
     hereby accepts:

               (a) LEASES. The Leases set forth on the Rent Roll attached hereto
          as Schedule 2;

               (b) PERSONAL PROPERTY.  All Personal Property,  including without
          limitation such items, if any,  specifically  identified on Schedule 3
          attached hereto;

               (c) INTANGIBLE PROPERTY. All Intangible Property; and

               (d) SERVICE CONTRACTS.  All Service Contracts,  if any, described
          in Schedule 4 attached hereto; and

               (e) APPURTENANCES AND APPURTENANT IMPROVEMENTS. All Appurtenances
          and Appurtenant Improvements.

          2. ASSUMPTION. LLC hereby assumes:

               (a) All of  Contributor's  obligations  under the Leases  arising
          from and after  Closing,  other  than  those  excepted  in  Schedule 5
          attached hereto,  but as to  Contributor's  obligations with regard to
          security deposits and other deposits,  only to the extent the security
          deposits have been transferred or credited to LLC;

               (b) All of the obligations of Contributor under Service Contracts
          arising from and after Closing; and

               (c) All of the obligations of Contributor under the Appurtenances
          arising from and after Closing.

          3.  WARRANTY.  Contributor  represents and warrants to LLC that it has
     not done or suffered to be done  anything  whereby the  property  described
     above is or may be  encumbered  or charged,  except for those arising under
     the  Permitted  Exceptions.   Contributor  shall  warrant  and  defend  the
     above-described  property unto LLC, its successors and assigns, against any
     person or entity  claiming,  or to claim,  the same or any part thereof by,
     from, or through Contributor, subject only to the Permitted Exceptions.
                                      -92-
<PAGE>
          4.  COUNTERPARTS;  FACSIMILE.  This  Agreement  may be executed in any
     number of  counterparts,  each of which shall be deemed to be an  original,
     and all of such counterparts shall constitute one Agreement.  To facilitate
     execution  of this  Agreement,  the parties  may  execute  and  exchange by
     telephone facsimile counterparts of the signature pages.


                                       CONTRIBUTOR:

                                       77 WEST WACKER LIMITED PARTNERSHIP

                                       By:  Prime Group Realty, L.P., a Delaware
                                       limited partnership, its general partner

                                       By:  Prime Group Realty Trust, a Maryland
                                       real estate investment trust, its
                                       managing general partner



                                       By:______________________________________
                                       Name:____________________________________
                                       Title:___________________________________

                                       LLC:

                                       77 WEST WACKER DRIVE, L.L.C.

                                       By:  Prime Group Realty, L.P., a Delaware
                                       limited partnership, its member

                                       By:  Prime Group Realty Trust, a Maryland
                                       real estate investment trust,its managing
                                       general partner



                                       By:______________________________________
                                       Name:____________________________________
                                       Title:___________________________________


                                       And By: OTR, an Ohio general partnership,
                                       acting on behalf of the State Teachers
                                       Retirement Systems of Ohio, an
                                       instrumentality of the State of Ohio, its
                                       member



                                       By:______________________________________
                                       Name:____________________________________
                                       Title:___________________________________











                                      -93-
<PAGE>
                                   SCHEDULE 1
                                   ----------

                                LEGAL DESCRIPTION
                                -----------------



























































                                      -94-
<PAGE>
                                   SCHEDULE 2
                                   ----------

                                     TENANTS
                                     -------



























































                                      -95-
<PAGE>
                                   SCHEDULE 3
                                   ----------

                                PERSONAL PROPERTY
                                -----------------



























































                                      -96-
<PAGE>
                                   SCHEDULE 4
                                   ----------

                                SERVICE CONTRACTS
                                -----------------



























































                                      -97-
<PAGE>
                                   SCHEDULE 5
                                   ----------

                              EXCEPTED OBLIGATIONS
                              --------------------


1.   Obligations  of lessor  under  Section 29 of Lease in favor of Jones,  Day,
     Reavis & Pogue LLP.

















































                                      -98-
<PAGE>
                                 APPENDIX 5.3(d)
                                 ---------------

                            TENANT AND VENDOR NOTICES
                            -------------------------
                                                                        [TENANT]


                               September __, 1999


VIA CERTIFIED MAIL/RRR
- ----------------------

______________________
______________________
______________________


    Re:  77 West Wacker, Chicago
         -----------------------


Dear Tenant:

     You are hereby advised that the above-referenced  property in which you are
a tenant was transferred  and your lease was assigned and transferred  effective
as of the date of this letter to 77 West Wacker Drive,  L.L.C.  (the "Company").
Your security  deposit and advance rental,  if any, have been transferred to the
Company.

     All future checks for rent and other charges should be made payable to:

                           77 West Wacker Drive, L.L.C.

         and forwarded to:

                           LaSalle National Bank
                           135 South LaSalle Street
                           Chicago, IL  60674-3806
                           Attention:  Dept. ______

         If Overnight:

                           LaSalle National Bank
                           200 West Monroe Street, Suite 200
                           Chicago, IL  60674-3806
                           Attention:_____________

     Building-related correspondence and notices to Landlord should be forwarded
to:

                           Prime Group, L.P.
                           77 West Wacker Drive
                           Suite 3900
                           Chicago, IL  60601
                           Attention:_____________


                                       77 WEST WACKER LIMITED PARTNERSHIP


                                       By:      ________________________________
                                       Name:    Jeffrey A. Patterson
                                       Its:     Executive Vice President





                                      -99-
<PAGE>
                                                                        [VENDOR]


                               September __, 1999



VIA CERTIFIED MAIL/RRR
- ----------------------

______________________
______________________
______________________


    Re:  77 West Wacker, Chicago
         -----------------------

Ladies and Gentlemen:

     This is to advise you that the above-referenced property was transferred to
77 West Wacker Drive,  L.L.C.  (the  "Company").  As part of the transfer,  your
contract has been assigned to the Company, and any goods,  services or utilities
supplied to the property  subsequent to the date of this letter shall be for its
account.  All future invoices and correspondence and andy and all Notices to the
Company  should  be sent to the  Company's  property  manager  at the  following
address:

                           Prime Group Realty, L.P.
                           c/o ____________________
                           77 West Wacker Drive
                           Suite 3900
                           Chicago, IL  60601


77 WEST WACKER LIMITED PARTNERSHIP

By:      Prime Group Realty, L.P.
Its:     General Partner

         By:      Prime Group Realty Trust
                  Managing General Partner

                  By:      ________________________
                  Name:    Jeffrey A. Patterson
                  Its:     Executive Vice President


















                                      -100-
<PAGE>
                                 APPENDIX 5.3(f)
                                 ---------------

                            Form of FIRPTA Affidavit

                                FIRPTA Affidavit



     Section 1445 of the Internal  Revenue  Code of 1986,  as amended,  provides
that a transferee of a United States real property interest must withhold tax if
the  transferor  is a foreign  person.  To inform  the  Transferee  (hereinafter
defined)  that  withholding  of tax is not required  upon the  disposition  of a
United States real property interest by 77 WEST WACKER LIMITED  PARTNERSHIP,  an
Illinois limited partnership (the "Transferor") to 77 WEST WACKER DRIVE, L.L.C.,
a Delaware limited liability company (the "Transferee"),  the undersigned, being
first duly sworn upon oath,  does hereby depose and say, and does hereby certify
the following on behalf of the Transferor:

     1. The  undersigned  is the  _________________  of Prime Group Realty Trust
("REIT"), a Maryland real estate investment trust, which is the managing general
partner of Prime Group Realty, L.P. ("OP"), a Delaware limited partnership which
is the general  partner of the  Transferor  and is familiar with the business of
the Transferor;

     2. The Transferor is not a foreign person; that is, the Transferor is not a
nonresident alien, a foreign corporation,  foreign partnership, foreign trust or
foreign  estate (as all such terms are defined in the  Internal  Revenue Code of
1986, as amended,  and United States Treasury  Department Income Tax Regulations
in effect as of the date hereof);

     3. The Transferor is a limited partnership duly organized, validly existing
and in good standing under the laws of the State of Illinois;

     4.  The  Transferor's  United  States  employer  identification  number  is
____________;

     5. The  Transferor's  office address and principal  place of business is 77
West Wacker Drive, Suite 3900, Chicago, Illinois 60601; and

     6. This  certificate  and  affidavit  is made to induce the  Transferee  to
consummate the transactions contemplated by the Transferor and Transferee.

     The  Transferor  understands  that this  affidavit and  certificate  may be
disclosed to the United States  Internal  Revenue  Service by the Transferee and
that  any  false  statement   contained   herein  could  be  punished  by  fine,
imprisonment, or both.

     Under penalties of perjury,  the undersigned  declares that he has examined
this affidavit and certificate,  and to the best of the undersigned's  knowledge
and belief, it is true, correct and complete.  The undersigned  further declares
that he has authority to sign this  affidavit and  certificate  on behalf of the
Transferor.











                                      -101-
<PAGE>
     This  affidavit and  certificate is executed and delivered as of the ______
day of _____________, 1999.


                                       77 WEST WACKER LIMITED PARTNERSHIP

                                       By:  Prime Group Realty, L.P.,
                                            a Delaware limited partnership,
                                            its general partner

                                       By:  Prime Group Realty Trust, a Maryland
                                            real estate investment trust, its
                                            managing general partner



                                       By:______________________________________
                                            Name:_______________________________
                                            Title:______________________________


STATE OF ______________ )
                        ) SS
COUNTY OF _____________ )

     The  foregoing  instrument  was  acknowledged  before  me the  _____ day of
______________,  1999 by  _________________________,  _________________ of Prime
Group Realty Trust, a real estate  investment  trust organized under the laws of
Maryland,  managing  general  partner of Prime  Group  Realty,  L.P.,  a limited
partnership  organized  under the laws of Delaware,  general  partner of 77 WEST
WACKER LIMITED  PARTNERSHIP,  a limited partnership  organized under the laws of
Illinois on behalf of the trust and such partnerships.


                                       _________________________________________
                                       Notary Public

                                       My Commission Expires:___________________


























                                      -102-
<PAGE>
                                 APPENDIX 6.1(e)
                                 ---------------

     Leasing Commissions Payable by 77 WWLP or Prime Following Closing Date


     77 WWLP shall be liable to pay as  provided  in Section  6.1(e) the leasing
commissions  incurred in connection  with the Leases  identified in section 1(a)
through (j) of the attached  Memorandum dated August 5, 1999 from Scott McKibben
to Steve  Huber (as  summarized  below),  excluding,  however,  any  commissions
relating to the  exercise of  extensions  or options to renew in the future,  if
any.

- ----------------------  ------------  ----------------  -------------------
       Tenant               RSF       Leasing Comm/RSF  Leasing Commissions
- ----------------------  ------------  ----------------  -------------------

Castle Creek                4,822         $  7.27            $  35,051
TDRC                        6,697         $  6.04            $  40,419
McGuire Wood Expansion        950         $  1.62            $   1,537
McGuire Wood Expansion     15,671         $  1.50            $  23,507
Microsoft                   2,424         $  4.53            $  10,993
Marakon                     1,424         $  3.25            $   4,630
USA Broadcasting            6,729         $  6.23            $  41,898
Jones Day                   4,991         $  1.30            $   6,489
PGRT                        2,685         $  1.50            $   4,028
Peregrin Capital            2,122         $  1.50            $   3,183
Carvill                     3,155         $  4.75            $  14,987
- ----------------------  ------------  ----------------  -------------------
Total Prime Obligation     51,670         $  3.61            $ 186,723
- ----------------------  ------------  ----------------  -------------------

































                                     -103-
<PAGE>
                                APPENDIX 6.10(a)

                         77 WWLP or Prime TI Obligations

     77 WWLP shall pay for all TI  Obligations  incurred in connection  with the
Leases  identified in section 1(a) through (h) of the August 5, 1999  Memorandum
attached to Appendix 6.1(e) (as summarized below).

- ----------------------  ------------  ----------------  -------------------
       Tenant               RSF       Leasing Comm/RSF  Leasing Commissions
- ----------------------  ------------  ----------------  -------------------

Castle Creek                4,822         $  30.00           $  144,660
TDRC                        6,697         $  35.50           $  237,744
McGuire Wood Expansion        950         $   0.00           $        0
Microsoft                   2,424         $  20.00           $   48,480
Marakon                     1,424         $  24.00           $   34,176
USA Broadcasting            6,729         $   8.57           $   57,650
Jones Day                   4,991         $  30.00           $  149,730
PGRT                        2,685         $  55.00           $  147,675
Peregrin Capital            2,122         $  40.00           $   84,880
Carvill                     3,155         $  10.00           $   31,550
- ----------------------  ------------  ----------------  -------------------
Total Prime Obligation     35,999         $  26.02           $  936,545
- ----------------------  ------------  ----------------  -------------------







































                                     -104-
<PAGE>
                                APPENDIX 6.10(b)
                                ----------------

                               LLC TI Obligations




- --------------------------------------------------------------
  Tenant                RSF            TI/RSF             TI
- --------------------------------------------------------------


RR Donnelly                                                             $100,000


Note:RR Donnelly is entitled to a $100,000  tenant  improvement  allowance after
     July, 2002.














































                                     -105-
<PAGE>
                                 APPENDIX 7.1(c)
                                 ---------------

                                 Tenant Defaults



- ----------------  ------------  ------------  ----------------
     Tenant            RSF      $ in Arrears     Date Due
- ----------------  ------------  ------------  ----------------
Cafe Baci             4,819     $ 144,373.00  1/1/96 - 9/1/98
Castle Creek          4,822     $  13,422.00  2/4/99 - 2/28/99
- ----------------                ------------
Total Defaults                  $ 157,795.00
- ----------------                ------------

















































                                     -106-
<PAGE>
                                 APPENDIX 7.1(o)
                                 ---------------

                                   Litigation





                             Intentionally Deleted






















































                                     -107-
<PAGE>
                                 APPENDIX 10.11
                                 --------------

                                   Notice List


77 WWLP and Prime:                  OTR
- ------------------                  ---

Jeffrey A. Patterson
Executive Vice President            Director, Real Estate Assets
and Chief Investment Officer        The State Teachers Retirement System of Ohio
Prime Group Realty Trust            275 East Broad Street
77 West Wacker, Suite 3900          Columbus, OH  43215-3771
Chicago, IL  60601                  Direct Dial:  (614) 227-4090
Direct Dial:  (312) 917-4230

                                    with a copy to:

                                    Outside Counsel
                                    ---------------
                                    Edward D. Diller, Esq.
with a copy to:                     Taft, Stettinius & Hollister LLP
                                    1800 Firstar Tower
In-House Counsel:                   425 Walnut Street
- -----------------                   Cincinnati, OH  45202-3957
James Hoffman                       Direct Dial:  (513) 381-2838
Senior Vice President
and General Counsel
Prime Group Realty Trust
77 West Wacker, Suite 3900
Chicago, IL  60601
Direct Dial:  (312) 917-4237































                                     -108-


                                 LOAN AGREEMENT




                                     Between

                       77 WEST WACKER LIMITED PARTNERSHIP
                              having an address at
                          c/o Prime Group Realty Trust
                        77 West Wacker Drive, Suite 3900
                             Chicago, Illinois 60601
                                  ("Borrower")

                                      -and-

                           WESTDEUTSCHE IMMOBILIENBANK
                              having an address at
                                 Wilhelm Theodor
                               Romheld Strasse 24,
                                   55130 Mainz
                           Federal Republic of Germany
                              ("Agent" or "Lender")

                                      -and-

                          LANDESBANK SCHLESWIG-HOLSTEIN
                              having an address at
                                  Martensdamm 6
                                   24103, Kiel
                           Federal Republic of Germany
                                   ("Lender")

                                      -and-

                          LANDESBANK SAAR GIROZENTRALE
                              having an address at
                                 Ursulinenstr. 2
                                66111 Saarbrucken
                           Federal Republic of Germany
                                   ("Lender")

                                      -and-


                                    DSL BANK
                              having an address at
                               Kennedyallee 62-70
                                   53175 Bonn
                           Federal Republic of Germany
                                   ("Lender")


                   (each Lender together with Agent "Lenders")


                         Dated: as of September 30, 1999




<PAGE>

                                TABLE OF CONTENTS
                                -----------------

                                                                            PAGE
                                                                            ----
                              ARTICLE 1 DEFINITIONS

Section 1.1   Definitions.................................................   1

                               ARTICLE 2 THE LOAN

Section 2.1   Loan........................................................   17
Section 2.2   Conditions Precedent........................................   17
Section 2.3   Interest....................................................   21
Section 2.4   The Note....................................................   21
Section 2.5   The Mortgage and Collateral.................................   21
Section 2.6   Default Rate................................................   22
Section 2.7   Repayment of Loan...........................................   22
Section 2.8   Prepayments.................................................   23
Section 2.9   Funding Loss................................................   23
Section 2.10  Taxes.......................................................   24
Section 2.11  Payments....................................................   25
Section 2.12  Distribution to Lenders.....................................   25
Section 2.13  Increased Costs; Overriding Events..........................   26
Section 2.14  Commitment Fee..............................................   28
Section 2.15  Arrangement Fee.............................................   28
Section 2.16  Lending Office..............................................   28

                    ARTICLE 3 REPRESENTATIONS AND WARRANTIES

Section 3.1   Good Standing of Borrower and its General Partners..........   28
Section 3.2   Authority of Borrower.......................................   28
Section 3.3   Authorizations..............................................   29
Section 3.4   Binding Agreement...........................................   29
Section 3.5   Litigation..................................................   29
Section 3.6   No Conflicts................................................   29
Section 3.7   Financial Conditions........................................   29
Section 3.8   Employee Benefit Plans......................................   30
Section 3.9   Governmental Plan...........................................   30
Section 3.10  Investment Company..........................................   30
Section 3.11  Hazardous Materials.........................................   30
Section 3.12  Solvency....................................................   30
Section 3.13  Borrower's Address..........................................   31
Section 3.14  Foreign Person..............................................   31
Section 3.15  Bankruptcy..................................................   31
Section 3.16  Compliance with Laws........................................   31
Section 3.17  Utility Service.............................................   31
Section 3.18  Access......................................................   32
Section 3.19  Insurance...................................................   32
Section 3.20  Rent Roll...................................................   32
Section 3.21  No Reliance on Agent or Lenders.............................   32

                  ARTICLE 4 AFFIRMATIVE AND NEGATIVE COVENANTS

Section 4.1   Affirmative Covenants.......................................   33
Section 4.2   Negative Covenants..........................................   40



                                      -i-
<PAGE>
                                                                            PAGE
                                                                            ----
                                ARTICLE 5 DEFAULT

Section 5.1   Events of Default...........................................   44
Section 5.2   Remedies....................................................   45
Section 5.3   Remedies Cumulative and Concurrent..........................   45
Section 5.4   Waiver, Delay or Omission...................................   45
Section 5.5   Indemnity...................................................   45

                     ARTICLE 6 LIMITED RECOURSE OBLIGATIONS

Section 6.1   Limited Recourse............................................   48

                               ARTICLE 7 THE AGENT

Section 7.1   Performance by Agent........................................   50
Section 7.2   Actions.....................................................   50
Section 7.3   Nonliability of Agent and Lenders...........................   50
Section 7.4   Authorization and Action....................................   51
Section 7.5   Withholding Exemption Certificates..........................   53
Section 7.6   Agent's Reliance, Etc.......................................   53

                             ARTICLE 8 MISCELLANEOUS

Section 8.1   Fees and Expenses...........................................   54
Section 8.2   Cumulative Rights and No Waiver.............................   54
Section 8.3   Notices.....................................................   55
Section 8.4   Severability................................................   55
Section 8.5   Binding Effect..............................................   55
Section 8.6   Execution in Counterparts...................................   55
Section 8.7   Time of the Essence.........................................   55
Section 8.8   Immunity....................................................   55
Section 8.9   Governmental Regulation of Lender...........................   56
Section 8.10  Modification, Waiver, Consent...............................   56
Section 8.11  Entire Agreement............................................   56
Section 8.12  Assignment..................................................   56
Section 8.13  Applicable Law..............................................   57
Section 8.14  Usury.......................................................   57
Section 8.15  Consent to Jurisdiction.....................................   58
Section 8.16  Monies......................................................   58
Section 8.17  Jury Trial..................................................   58

EXHIBIT A     Cash Collateral Agreement (Ratio Reserve)
EXHIBIT B     Description of Land
EXHIBIT C     Leases
EXHIBIT D     Permitted Encumbrances
EXHIBIT E     Principal Repayment Schedule
EXHIBIT F     Designation Notice



















                                      -ii-
<PAGE>
                                 LOAN AGREEMENT
                                 --------------

     This Loan Agreement (this  "Agreement") is made and entered into as of this
30th day of September 1999, by and between 77 WEST WACKER,  LIMITED PARTNERSHIP,
a limited  partnership  organized  and  existing  under the laws of the State of
Illinois ("Borrower"),  and WESTDEUTSCHE  IMMOBILIENBANK,  a banking institution
organized under the laws of the Federal  Republic of Germany,  having an address
at Wilhelm Theodor Romheld Strasse 24, 55130 Mainz, Federal Republic of Germany,
individually and as agent (including any of its successors and assigns, "Agent")
for LANDESBANK  SCHLESWIG-HOLSTEIN,  a banking  institution  organized under the
laws of the Federal  Republic of Germany,  having an address at  Martensdamm  6,
24103,  Kiel,  Federal  Republic of Germany,  LANDESBANK  SAAR  GIROZENTRALE,  a
banking institution organized under the laws of the Federal Republic of Germany,
having an address at  Ursulinenstr.  2, 66611  Sarrbrucken,  Federal Republic of
Germany, DSL BANK, a banking institution organized under the laws of the Federal
Republic  of  Germany,  having an address at  Kennedyallee  62-70,  53175  Bonn,
Federal Republic of Germany, and such other co-lenders as may exist from time to
time (collectively with Agent, "Lenders" and each individually, "Lender").

                              W I T N E S S E T H:
                              --------------------

     WHEREAS,  Borrower owns fee title to the Premises and leasehold interest in
the Leasehold; and

     WHEREAS,  Borrower  and Lenders have agreed,  among other  things,  for the
Lenders to make a loan to  Borrower  in the  aggregate  principal  amount of One
Hundred Seventy Million Dollars  ($170,000,000.00) (the "Loan") evidenced by the
certain Promissory Note from Borrower to Lenders dated as of the date hereof, in
the amount of ONE HUNDRED SEVENTY MILLION DOLLARS ($170,000,000.00) (the "Note")
subject to the terms and conditions hereinafter set forth.

     NOW  THEREFORE,  in  consideration  of the  foregoing  and  other  good and
valuable  consideration,  the  receipt  and  sufficiency  of  which  are  hereby
acknowledged, Borrower and each Lender agree as follows:


                                    ARTICLE 1
                                   DEFINITIONS

     Section 1.1 DEFINITIONS.

     Terms used but not  defined  in the  Agreement  shall  have the  respective
meanings ascribed to them below:

     "Acceptable  Letter  of  Credit"  means  a  letter  of  credit  issued  (or
confirmed)  by a Qualified  Bank to the Agent as provided for in Section  4.1(h)
hereof (i) providing for  presentation and payment at such Qualified Bank's main
office or a branch  office,  in either case which is acceptable to the Agent (it
being agreed that a New York main or branch office of a Qualified  Bank shall be
acceptable to the Agent for this purpose); (ii) in respect of which Borrower may
not provide any  collateral to, or for the benefit of, the issuer of such letter
of credit if, as a result of such collateralization,  the rights of the Lenders,
or any  assignee of such,  would or would  likely be  adversely  affected by the
application of any bankruptcy or insolvency law applicable to Borrower; (iii) in
respect of which the issuer  shall  expressly  waive any rights of  subrogation;
(iv) which shall be payable in  Dollars;  (v) having an expiry date at least one
year from the date of issuance and containing  automatic renewal provisions (and
providing  that  such  letter  of  credit  may be  drawn  20 days  prior  to the
expiration  thereof unless renewed,  replaced or extended prior  thereto);  (vi)
entitling the beneficiary thereof to assign its interest therein to a transferee


                                      -1-
<PAGE>
of the Agent without the consent of the Borrower or the issuer of such letter of
credit, and requiring the issuer of such letter of credit, after the date of any
such transfer and upon the request of such transferee,  to issue a new letter of
credit in favor of such  transferee  in exchange for such issuer being  released
from its  obligations  under the  letter of credit in favor of the  transferring
Agent;  (vii)  governed by the  Uniform  Customs and  Practice  for  Documentary
Letters of Credit (the  "Uniform  Customs"),  and to the extent not addressed by
the Uniform Customs,  governed by New York law, and containing an express waiver
of  Section  5-112 of New  York  Uniform  Commercial  Code  (or any  similar  or
replacement  provision  therefor);  and (viii)  containing  the letter of credit
issuer's  agreement  that,  if an event of  "force  majeure"  shall  occur,  the
expiration  date of the letter of credit  shall be extended to a date that is at
least 30 days following the time the force majeure ceases to exist.

     "Affiliate"  means,  as to any Person,  any other Person that,  directly or
indirectly,  controls,  is  controlled  by or is under common  control with such
Person or is a director or officer of such Person.

     "Agent's  Address"  means  Westdeutsche  ImmobilienBank,   Wilhelm  Theodor
Romheld Strasse 24, 55130 Mainz,  Federal  Republic of Germany,  Attention:  Dr.
Jurgen Gerber or Mr. Armin  Gemmerich,  Telecopier  Number:  +49 6131 928 308 or
such  other  office  Agent  designates  from time to time by  written  notice to
Borrower.

     "Annual  Installment  Payment"  has the  meaning  set forth in Section  2.7
hereof.

     "Applicable  Margin"  shall be (i) 1.25% or (ii) in the event that the Loan
to Value Ratio shall exceed 65% on any LTV  Determination  Date (as  hereinafter
defined),  1.35% until the occurrence of a LTV  Determination  Date on which the
Loan to  Value  Ratio  shall be equal to or less  than  65%,  at which  time the
Applicable Margin will be 1.25%.

     "Appraisal" has the meaning set forth in Section 4.1(g) hereof.

     "Asbestos" means any hydrated mineral silicate  separable into commercially
usable fibers,  including, but not limited to, chrysolite (serpentine),  amosite
(cummingtonite-grunerite),  crocidolite (riebecktite),  tremolite,  anthophylite
and actinolite. "Asbestos-containing Material" means any material which contains
1% or more Asbestos by weight.

     "Assignment of Contracts and Authorizations"  means that certain Assignment
of Contracts and  Authorizations  between  Borrower and Lenders  executed on the
Closing Date.

     "Assignment  of Leases and Rents" means that certain  Assignment  of Leases
and Rents between Borrower and Lenders executed on the Closing Date.

                  "Borrower's Address" means:

                        c/o Prime Group Realty Trust
                        77 West Wacker Drive, Suite 3900
                        Chicago, Illinois  60601
                        Attention:  Jeffrey A. Patterson and Louis G. Conforti

                  with a copy to

                        c/o Prime Group Realty Trust
                        77 West Wacker Drive, Suite 3900
                        Chicago, Illinois  60601
                        Attention:  General Counsel



                                      -2-
<PAGE>
     "Business  Day"  means any day  other  than a  Saturday  or Sunday on which
commercial  banks are open for domestic and  international  business  (including
dealings in dollar deposits) in New York City, USA, Chicago,  Illinois, USA, and
Mainz, Federal Republic of Germany.

     "Cash  Collateral  Account (Central  Account)" means the  interest-bearing,
U.S. Dollar depository account maintained by Borrower with LaSalle National Bank
(or a comparable  account at another bank in New York City or Chicago,  Illinois
that is reasonably acceptable to Agent), for the purpose of holding certain cash
deposits  made  by  Manager,  Borrower  or the  tenants  under  the  Leases,  in
connection  with or pursuant to the payment of Rent by tenants under the Leases,
which  cash  deposits  shall be  pledged  to Agent  as  collateral  for the Loan
pursuant to the Cash Collateral Agreement (Central Account).

     "Cash Collateral Account (Ratio Reserve)" means the interest-bearing,  U.S.
Dollar depository  account maintained by Borrower with LaSalle National Bank (or
a comparable account at another bank in New York City or Chicago,  Illinois that
is  reasonably  acceptable  to Agent),  for the purpose of holding  certain cash
deposits made by Borrower pursuant to Section 4.1(g) hereof, which cash deposits
shall be  pledged  to  Agent as  collateral  for the Loan  pursuant  to the Cash
Collateral Agreement (Ratio Reserve).

     "Cash   Collateral   Account   (Tenant   Allowance   Reserve)"   means  the
interest-bearing,  U.S. Dollar  depository  account  maintained by Borrower with
LaSalle National Bank (or a comparable  account at another bank in New York City
that is reasonably acceptable to Agent), for the purpose of holding certain cash
deposits made by Borrower pursuant to Section 4.1(h) hereof, which cash deposits
shall be  pledged  to  Agent as  collateral  for the Loan  pursuant  to the Cash
Collateral Agreement (Tenant Allowance Reserve).

     "Cash  Collateral  Agreement  (Central  Account)"  means that  certain Cash
Collateral  Agreement  (Central  Account) between Borrower and Agent executed on
the Closing Date.

     "Cash  Collateral  Agreement  (Ratio  Reserve)"  means  a  Cash  Collateral
Agreement (Ratio Reserve)  between Agent and Borrower in the form  substantially
the same as that attached hereto as Exhibit A.

     "Cash Collateral  Agreement (Tenant Allowance  Reserve)" means that certain
Cash Collateral  Agreement (Tenant Allowance Reserve) between Agent and Borrower
executed on the Closing Date.

     "Cash  Expenditures"  means the  aggregate  costs paid by  Borrower  in the
ordinary  course of  maintaining  and  operating  the  Premises  (determined  in
accordance  with the cash method of accounting),  including (i)  installments of
principal and interest  payable by Borrower to Agent or Lenders  pursuant to the
terms of the Loan Documents,  (ii) Operating Expenses,  (iii) Income Taxes, (iv)
repayments of Qualified Loans,  (v) all costs and expenses  incurred by Borrower
for capital improvements to the Premises, other than Tenant  Improvement/Leasing
Commission  Costs  made in  accordance  with the  Loan  Documents,  (vi)  Tenant
Improvement/Leasing  Commission  Costs,  (vii)  deposits in the Cash  Collateral
Account (Tenant Allowance Reserve) and (viii) amounts with respect to any of the
items set forth in clauses (ii) - (vi) above  which,  in  Borrower's  reasonable
judgment,  are of a magnitude that merits the  establishment of reserves for the
payment thereof over a period of no less than two months.

     "Cash  Receipts" means all income of any kind received by, or on behalf of,
Borrower from the Premises  (determined  in  accordance  with the cash method of
accounting),  including all fixed rent,  percentage rent,  escalation  payments,
storage income,  tenant work order income, cost recoveries and similar operating
income items whether or not derived from the Leases.



                                      -3-
<PAGE>
     "Closing"  means the time of the execution and delivery  hereof by Borrower
and Lenders and the funding of the Loan.

     "Closing Date" means the date of Closing.

     "Code"  means  the  Internal  Revenue  Code of 1986,  as  amended,  and any
successor thereto.

     "Collateral" means (i) the Mortgaged Property (as defined in the Mortgage),
(ii) the Cash Collateral  Account  (Central  Account),  and (iii) any collateral
delivered  to Agent in  accordance  with  Sections  4.1(g)  and  4.1(h)  hereof,
inclusive,  including,  but not limited to, the Cash  Collateral  Account (Ratio
Reserve) and the Cash Collateral Account (Tenant Allowance Reserve).

     "Control"  (including the terms  "controlling",  "controlled by" and "under
common control with") of a Person means the possession,  direct or indirect,  of
the  power to vote 50% or more of the  outstanding  equity  securities  or other
ownership  interests  of such Person or to direct or cause the  direction of the
management  and policies of such Person,  whether  through the  ownership of the
outstanding  equity  securities  or other  ownership  interests,  by contract or
otherwise.

     "Debt Service" shall mean, with respect to any period, any and all interest
and scheduled payments of principal required to be made under the Loan Documents
during such period;  provided,  however, that for the purpose of calculating the
Debt Service Coverage Ratio payments of principal required shall be deemed to be
on the basis of a thirty (30) year  amortization  schedule in lieu of the actual
amortization schedule required under the Loan Documents.

     "Debt  Service  Coverage  Ratio" or "DSCR"  shall mean with  respect to any
twelve (12) month period  ending on December 31 (or with respect to the calendar
year in which the Loan is made,  such  shorter  period  ending on  December  31,
1999), the ratio of Net Operating Income (excluding tenant improvement costs and
leasing  commissions) for such twelve (12) month period to Debt Service for such
twelve (12) month period as evidenced in the financial statements to be provided
to Agent  by  Borrower  pursuant  to  Section  4.1(a)(i)  and (iv)  (hereinafter
referred to as the "DSCR Financial Statements"). If applicable, at any time that
Agent is in  possession  of  collateral  that has been  delivered to it by or on
behalf of Borrower in  accordance  with  Sections  4.1(g) and 4.1(h),  the "Debt
Service  Coverage  Ratio" shall be  calculated as if the amount of Net Operating
Income  for the  period in  question  included  the value of the  collateral  so
delivered to Agent.

     "Default Rate" has the meaning set forth in Section 2.6 hereof.

     "DSCR  Determination  Date" has the  meaning  ascribed  thereto  in Section
4.1(g) hereof.

     "DSCR  Financial  Statements"  has  the  meaning  ascribed  thereto  in the
definition of Debt Service Coverage Ratio.

     "Environmental   Indemnity  Agreement"  means  that  certain  Environmental
Indemnity Agreement between Borrower and Lenders executed on the Closing Date.

     "Environmental  Law" means any federal,  state,  local or foreign  statute,
law,  ordinance,  rule,  regulation,  code, order, writ,  judgment,  injunction,
decree or  judicial  or  mandatory  agency  interpretation,  policy or  guidance
relating to  pollution  or  protection  of the  environment,  health,  safety or
natural resources,  including,  without  limitation,  those relating to the use,
handling, transportation,  treatment, storage, disposal, release or discharge of
Hazardous  Materials  applicable  to the  Premises  or the  Leasehold  or  their
management, use or operation.


                                      -4-
<PAGE>
     "Environmental  Site  Assessment"  means that certain Phase I Environmental
Site Assessment 77 West Wacker Drive, Chicago, Illinois 60601 for 77 West Wacker
Limited   Partnership,   Project   Number   3157.190   prepared  by  Hygienetics
Environmental Services, Inc., 10 South Riverside Plaza, Chicago, Illinois 60606,
dated July 13, 1999.

     "ERISA"  means the Employee  Retirement  Income  Security  Act of 1974,  as
amended from time to time, and the  regulations  promulgated  and rulings issued
thereunder.

     "Event(s) of Default" has the meaning set forth in Section 5.1 hereof.

     "Fiscal Year" means a fiscal year of Borrower  ending on December 31 in any
calendar year or such other fiscal year as Borrower may select from time to time
in accordance with the terms of this Agreement.

     "Fixtures" means all property and equipment now owned or hereafter acquired
by Borrower and now or hereafter  located under, on or above the Premises or the
Leasehold and owned by Borrower,  whether or not permanently  affixed,  which to
the fullest extent permitted by applicable law in effect from time to time shall
be deemed fixtures and a part of the Premises or the Leasehold.

     "Floating  Rate"  means,  for any  LIBOR  Interest  Period,  at  Borrower's
election,  indicated by  telephonic  notice,  followed by written  confirmation,
given by Borrower to Agent no later than 11:00 a.m. New York City time, at least
three (3) LIBO Business Days prior to the commencement date of the first or next
succeeding LIBOR Interest Period, LIBOR plus the Applicable Margin.

     "Foreign Person" has the meaning set forth in Section 3.14 hereof.

     "GAAP" or "Generally Accepted Accounting  Principles" shall mean accounting
principles  as  generally  accepted  in the  United  States  and as set forth in
statements of the Financial Accounting Standards Board and/or in the Opinions of
the Accounting  Principles  Board of the American  Institute of Certified Public
Accountants,  or such other  accounting  principles as may be mutually agreed by
Lender and Borrower.

     "Governmental  Authority(ies)" means any (federal, state, county, municipal
or other government) governmental department,  commission, board, bureau, court,
agency or any  instrumentality of any of them having jurisdiction over Borrower,
the Premises and/or the Leasehold.

     "Governmental Requirement" means any law, statute, code, ordinance,  order,
rule,  regulation,  judgment,  decree,  writ,  injunction,   franchise,  permit,
certificate, license, authorization, or other mandatory direction or requirement
of any  Governmental  Authority  now  existing or  hereafter  enacted,  adopted,
promulgated,  entered,  or issued  applicable  to the  Premises,  the  Leasehold
Premises or Borrower.

     "Grace  Period" means the period from and after the Maturity  Date,  until,
and including, the Grace Period Termination Date.

     "Grace Period Termination Date" means September 29, 2005.

     "Guaranty"  means the Guaranty  provided by Prime and/or OSTRS, as the case
may be, pursuant to Section 4.1(h) hereof, of Borrower's obligations to make the
deposits to the Cash Collateral  Account (Tenant Allowance  Reserve) as provided
in  Section  4.1(h)  hereof,  such  Guaranty  providing  that in the event  that
Borrower fails to make the required  deposits into the Cash  Collateral  Account
(Tenant  Allowance  Reserve),  the guarantor under the Guaranty shall either pay
the portion of the Required  Amount then  outstanding  into the Cash  Collateral
Account (Tenant Allowance Reserve) or to Agent, as Agent shall instruct.


                                      -5-
<PAGE>
     "Hazardous Material" means any flammable explosives, radioactive materials,
Asbestos, and any chemical, petroleum products, or other man-made materials with
hazardous or carcinogenic toxic characteristics,  including, without limitation,
any  substances   defined  as  or  included  in  the  definition  of  "hazardous
substances",  "hazardous  waste",  "hazardous  materials",  "toxic  substances",
"contaminants",  or  other  similar  terms,  by  any  federal,  state  or  local
environmental statute, regulation or ordinance presently or hereafter in effect,
as such statute, regulation or ordinance may be amended from time to time.

     "Impositions"  means all (i) real estate and  personal  property  taxes and
other  taxes and  assessments,  public or  private;  utility  rates and  charges
including those for water and sewer; all other governmental and non-governmental
charges  and any  interest  or costs or  penalties  with  respect  to any of the
foregoing; and charges for any public improvement, general and special, ordinary
and  extraordinary,  foreseen and unforeseen,  of any kind and nature whatsoever
that at any time prior to or after the  execution of the Loan  Documents  may be
assessed  against  Borrower  and levied or  imposed  upon the  Premises  and the
Leasehold  Premises  or the rents or income  received  therefrom,  or any use or
occupancy thereof which become due and payable during the term of the Loan, (ii)
other taxes,  assessments,  fees and governmental and  non-governmental  charges
levied imposed or assessed upon or against Borrower which become due and payable
during the term of the Loan and (iii) taxes levied or assessed upon the Mortgage
and the Note which  become due and  payable  during the term of the Loan  (other
than (a) income, gross receipts,  franchise, gift, inheritance and similar taxes
imposed upon Lenders or any tax imposed in lieu of or as a direct substitute for
any such  income,  gross  receipts  and similar  taxes,  (b) any taxes levied or
assessed  in  connection  with a  Lender's  transfer  of all or any  part of its
interest in the Loan,  except any transfer taxes imposed on the initial transfer
of interests in the Loan by Agent within  twelve (12) months of the Closing Date
by any federal,  state or local  government  in the United States of America and
(c) taxes imposed by the Federal Republic of Germany).

     "Improvements" has the meaning specified in the Mortgage.

     "Income  Taxes"  means all federal,  state and local  income taxes  payable
(including  installment and estimated payments in respect thereof),  directly or
pursuant to a tax allocation  agreement or successor  agreement,  by Borrower or
its direct and indirect  partners with respect to the taxable  income derived or
received from the Premises and the Leasehold Premises.

     "Institution"  means (a) a commercial  bank organized under the laws of the
United States,  or any State thereof,  or a commercial  bank organized under the
laws  of  another  country,  in  any  case  having  a net  worth  in  excess  of
$500,000,000,  any holding company thereof and any affiliate  having a net worth
in excess of  $500,000,000 of any such holding  company;  (b) a savings and loan
association  or savings bank organized  under the laws of the United States,  or
any State thereof, and having a net worth in excess of $250,000,000, any holding
company  thereof and any affiliate  having a net worth in excess of $250,000,000
of any such holding  company;  and (c) any  insurance  company,  pension fund or
investment fund having a net worth in excess of $500,000,000. Nothing in clauses
(a) through (c) of the  immediately  preceding  sentence to the  contrary,  each
Lender shall be deemed an "Institution".

     "JV Agreement" means that certain Amended and Restated Operating Agreement,
to be entered  into by OSTRS and Prime and  approved  by Agent,  relating to the
ownership of the Premises.

     "Land" means the real  property  more  particularly  described in Exhibit B
attached hereto and by this reference made a part hereof.

     "Laws"  means all present and future  laws,  statutes,  codes,  ordinances,
orders, judgments,  decrees,  injunctions,  rules, regulations,  determinations,
awards and court orders of any federal,  state,  municipal or local  government,

                                      -6-
<PAGE>
Governmental  Authority,  regulatory agency or authority applicable to Borrower,
the Leasehold and/or the Premises by 77 West Wacker Drive, L.L.C. (the "JV").

     "Leasehold"  means Borrower's  leasehold  interest in that certain premises
(the "Leasehold  Premises")  located adjacent to the Premises,  pursuant to that
certain  Lease  (the "Air  Rights  Lease"),  dated as of March 7,  1991,  by and
between  American  National Bank and Trust Company of Chicago as T/u/T 66121, as
landlord, and Borrower, as tenant. The parties hereto acknowledge and agree that
Borrower  does  not own a fee  interest  in the  Leasehold  Premises  and is not
subject to or obligated in any way with respect to such fee interest,  except as
otherwise set forth in the Air Rights Lease.

     "Leases"  means any and all leases,  subleases,  licenses,  concessions  or
grants of other possessory  interest now or hereafter in force, oral or written,
covering or  affecting  the  Premises  or the  Leasehold  Premises,  or any part
thereof, including, without limitation, the leases set forth on Exhibit C hereto
(true and complete copies of which have been delivered to the Agent prior to the
date hereof).

     "Lending Office" shall mean:

                  For Agent, in its capacity as Lender:

                           Wilhelm Theodor Romheld Strasse 24
                           55130 Mainz
                           Federal Republic of Germany
                           Attention:  Dr. Jurgen Gerber or Mr. Armin Gemmerich

                  For LANDESBANK SCHLESWIG-HOLSTEIN:

                           Martensdamm 6
                           24103 Kiel
                           Federal Republic of Germany
                           Attention:  Stefan Kolle

                  For LANDESBANK SAAR GIROZENTRALE

                           Ursulinenstr. 2
                           66111 Sarrbrucken
                           Federal Republic of Germany
                           Attention: Mr. Hoffmann

                  For DSL BANK:

                           Kennedy allee 62-70
                           53175 Bonn
                           Federal Republic of Germany
                           Attention:  Horst Willemse

or such  other  office  as each of the  above  mentioned  Lenders,  on any other
Lender,  shall  designate  from time to time by written  notice to Borrower  and
Agent given at least three (3) Business Days prior to the effective date of such
notice.

     "LIBO  Business Day" means a day other than (i) Saturday,  (ii) Sunday,  or
(iii) a day on which  commercial  banks  in New  York  City,  United  States  of
America, London, England or Mainz, Germany are required by law to close.

     "LIBO Reserve  Percentage"  means the percentage  representing  the reserve
requirement  applicable to Eurocurrency  Liabilities pursuant to Regulation D of
the Board of Governors of the Federal Reserve System (or any successor thereto).
In determining  the LIBO Reserve  Percentage,  Agent shall take into account any


                                      -7-
<PAGE>
transitional  adjustment  or phase-in  provisions  of the  reserve  requirements
otherwise  applicable to Eurocurrency  Liabilities  during the applicable  LIBOR
Interest  Period,  and, in the event of any change or  variation  in the reserve
requirements  during the  applicable  LIBOR Interest  Period,  Agent may use any
reasonable  averaging or  attribution  methods which it deems  appropriate.  The
determination  by Agent  of any  applicable  LIBO  Reserve  Percentage  shall be
conclusive,  absent  manifest  error.  Failure by Agent to take into account the
LIBO  Reserve  Percentage  when  calculating  interest  due with  respect to the
outstanding indebtedness of the Loan shall not constitute,  whether by course of
dealing or otherwise, a waiver by Agent of its right to collect such amounts for
any future period.

     "LIBOR"  means,  as to the  outstanding  indebtedness  owed  hereunder with
respect to the applicable LIBOR Interest Period, (a) the rate per annum equal to
the offered rate for deposits in United States dollars for the applicable  LIBOR
Interest  Period  and  for  the  amount   comparable  to  the  then  outstanding
indebtedness of the Loan,  which appears on Dow Jones Markets Service  (formerly
known as Telerate) display page 3750 as of 11:00 a.m. (London time) two (2) LIBO
Business  Days  prior  to the  first  day of such  LIBOR  Interest  Period  (the
"Determination Date") divided by (b) one minus the LIBO Reserve Percentage. "Dow
Jones Markets Service  display page 3750" means the display  designated as "page
3750" on the Dow Jones  Markets  Service (or such other page as may replace page
3750 on that  service or such other  service as may be  nominated by the British
Bankers'  Association  as the  information  vendor for the purpose of displaying
British  Bankers'   Association   Interest  Settlement  Rates  for  U.S.  Dollar
deposits).  If such rate does not appear on Dow Jones Markets  Service page 3750
as of  approximately  11:00 a.m.  (London time) on the  Determination  Date, the
LIBOR for the LIBOR  Interest  Period will be reasonably  determined by Agent in
good faith on a customary commercial basis on the basis of the offered rates for
deposits  in U.S.  Dollars  for an  amount  comparable  to the then  outstanding
indebtedness  of the Loan for the same  period  of time as such  LIBOR  Interest
Period that are offered by four (4) major banks in the London  interbank  market
at approximately  11:00 a.m. (London time) on the Determination Date. Agent will
request  that the  principal  London  office of each of the four (4) major banks
provide a quotation of its U.S. Dollar deposit offered rate. If at least two (2)
such  quotations  are  provided,  the LIBOR will be the  arithmetic  mean of the
quotations.  If fewer than two (2)  quotations  are provided as  requested,  the
LIBOR  will be  reasonably  determined  by  Agent in good  faith on a  customary
commercial  basis on the basis of the rates quoted for loans in U.S.  Dollars to
leading   European  banks  for  amounts   comparable  to  the  then  outstanding
indebtedness  of the Loan for the same  period  of time as such  LIBOR  Interest
Period offered by major banks in New York City at approximately  11:00 a.m. (New
York  time) on the  Determination  Date.  If at least two (2) such  rates are so
provided, the LIBOR will be the arithmetic mean of the quotations. If fewer than
two (2) rates are provided, the LIBOR which was used to determine the last LIBOR
in effect shall be deemed to be the LIBOR.

     "LIBOR  Interest  Period" means,  for any  outstanding  indebtedness of the
Loan,  the time  during  which the  applicable  Floating  Rate is in effect with
respect to such amount and shall mean the period commencing,  (i) in the case of
the first LIBOR  Interest  Period on the Closing Date,  and (ii) with respect to
any  subsequent  LIBOR  Interest  Periods,  on the last  day of the  immediately
preceding  LIBOR  Interest  Period,  and ending,  in each case, at the option of
Borrower, as provided below, thirty (30), sixty (60), ninety (90) or one hundred
and eighty (180) days thereafter;  provided, however, that whenever the last day
of any LIBOR Interest  Period would  otherwise  occur on a day other than a LIBO
Business  Day, the last day of such LIBOR  Interest  Period shall be extended to
occur on the next  succeeding LIBO Business Day,  provided  further that if such
extension would cause the last day of such LIBOR Interest Period to occur in the
next following  calendar month, the last day of such LIBOR Interest Period shall
occur on the immediately preceding LIBO Business Day.



                                      -8-
<PAGE>
     "Lien" means, for purposes of this Agreement and with respect to any asset,
any mortgage,  deed of trust, lien, pledge,  charge,  security interest or other
encumbrance of any kind in respect of such asset,  including without  limitation
any right or  arrangement  with any creditor to have its claim  satisfied out of
such asset,  or the proceeds  therefrom,  prior to the general  creditors of the
owner thereof.

     "Loan  Documents"  means  all  instruments  and  agreements   executed  and
delivered,  or to be executed and delivered by Borrower, to Agent and/or Lenders
in connection with the Loan,  each in form and substance  acceptable to Agent in
its reasonable discretion. By way of example, but not limitation, such documents
shall include (i) the Note, (ii) the Mortgage,  (iii) this  Agreement,  (iv) the
Environmental  Indemnity  Agreement,  (v) the Cash Collateral Agreement (Central
Account)  and (vi)  all  such  other  instruments  as  Agent  in its  reasonable
discretion shall require.

     "Loan to Value Ratio" means the  percentage  which results from a fraction,
the numerator of which shall be equal to the then  outstanding  principal amount
of the Loan minus the value of any  collateral  that has been delivered by or on
behalf of  Borrower  to Agent in  accordance  with  Sections  4.1(g)  and 4.1(h)
hereof,  and the  denominator of which shall be equal to the appraised  value of
the  Premises(as  determined  by the most recent  Appraisal  as of the date such
ratio is being computed).

     "LTV Determination Date" means the date of any Appraisal delivered to Agent
pursuant to Section 4.1(g) hereof or obtained by Agent pursuant thereto.

     "Majority Lenders" means, at any time, Lenders owed more than sixty-six and
two- thirds percent (66_%) of the then aggregate  unpaid principal amount of the
Loan.

     "Management  Agreement" means the Asset and Property Management  Agreement,
dated as of the Closing Date, between Borrower and Manager.

     "Manager" means Prime Group Realty, L.P., Prime Group Realty Services, Inc.
or another Affiliate of Borrower or any other Person retained by Borrower as its
property  manager and  approved by Agent with  respect to the  Premises  and the
Leasehold Premises in accordance with the terms of the Loan Documents. "Maturity
Date" means September 29, 2004.

     "Mortgage"  means the Mortgage,  Assignment  of Leases and Rents,  Security
Agreement and Fixture Filing dated as of the date hereof by Borrower in favor of
Lenders.

     "Mortgage  Insurance  Policy"  means a final,  marked  commitment  of title
insurance  containing such coverages as Agent reasonably  deems necessary,  with
all general survey exceptions deleted, on forms of, and issued by, Chicago Title
Insurance  Company  and/or  such  other  title  insurance  companies  as  may be
reasonably acceptable to Agent insuring the priority of the Lien on the Land and
the improvements created by the Mortgage.

     "Net Cash Flow" means,  for any period,  the excess of Cash  Receipts  over
Cash Expenditures.

     "Net  Operating  Income"  shall  include the  Operating  Income  accrued by
Borrower  for the  applicable  calendar  year  less all  Operating  Expenses  in
connection  with the  operation  of the  Premises,  all the  foregoing  being in
accordance with Generally Accepted Accounting Principles.

     "Operating  Expenses"  means,  with  respect to any period,  all  operating
expenses of the  Premises  including  costs  incurred  for  utilities,  repairs,
maintenance,   security,   cleaning,   salaries  and  payroll,   administrative,


                                      -9-
<PAGE>
marketing,  legal and other  professional  services,  management fees payable to
Manager, real estate taxes and insurance premiums and such other expenses as are
determined  in  accordance  with  Generally   Accepted   Accounting   Principles
consistently applied, except depreciation associated with the Premises.

     "Operating  Income" means, with respect to any period, all of the Rents (as
hereinafter  defined),  revenues and income  under the Leases (but  specifically
excluding  security  deposits  unless  and to the  extent  same are used to cure
defaults)  and/or arising from the use or enjoyment of all or any portion of the
Premises and all other amounts  received  which,  in accordance  with  Generally
Accepted  Accounting  Principles,  are  required to be  included  in  Borrower's
financial statement as operating income of the Premises.

     "Opinion of  Borrower's  Counsel"  means an opinion of counsel of Borrower,
Winston & Strawn,  in form and substance  reasonably  satisfactory  to Agent and
Agent's counsel.

     "Organizational  Documents"  means (i) with respect to any Person that is a
corporation,  the  certificate of  incorporation  or charter and by-laws of such
Person,  (ii) with respect to any Person that is a partnership,  the partnership
agreement and, if a limited  partnership,  certificate of limited partnership of
such Person,  and (iii) with  respect to any Person that is a limited  liability
company,  the  articles of  organization  and the  operating  agreement  of such
Person.

     "OSTRS"  means OTR, an Ohio  general  partnership,  acting on behalf of and
legally binding the State Teachers Retirement System of Ohio, an instrumentality
of the State of Ohio.

     "Other Taxes" mean any present or future stamp or documentary  taxes or any
other  excise or  property  taxes,  charges or similar  levies  which arise from
payment  made  hereunder  or under the Note or from the  execution,  delivery or
recording  of, or  otherwise  with respect to, this  Agreement,  the Note or the
Mortgage  imposed  by the  United  States or any state  thereof  (including  any
political subdivision or taxing authority thereof), other than (i) income, gross
receipts, franchise, inheritance, gift and similar taxes imposed upon Lenders or
any tax imposed in lieu of and as a direct substitute for any such income, gross
receipts,  and similar taxes and (ii) any taxes levied or assessed in connection
with a Lender's  transfer of all or any part of its interest in the Loan, except
any transfer  taxes imposed on the initial  transfer of interests in the Loan by
Agent within  twelve (12) months of the Closing  Date by any  federal,  state or
local government in the United States of America.

     "Permitted  Encumbrances"  means those matters listed in Exhibit D attached
hereto and made a part hereof, to which the interest of Borrower in the Premises
is permitted to be subject.

     "Permitted   Transferee"   means  a   corporation,   partnership,   limited
partnership or limited  liability  company,  that is not a Foreign Person and is
Controlled  by Prime or OSTRS or both (or is under  common  control  by Prime or
OSTRS or both).

     "Person"  means  an  individual,  partnership,   corporation  (including  a
business  trust),  limited  liability  company,  joint  stock  company,   trust,
unincorporated  association,  joint venture or other entity,  or a government or
any political subdivision or agency thereof.

     "Permitted  Exceptions"  means (a) Liens in favor of Lender,  (b) Permitted
Prior  Exceptions,  (c) Leases to which  Lender has  provided its consent (or is
otherwise  deemed to have given) pursuant to Section 4.1(r) hereof and (d) other
matters  expressly   approved  by  Lender  in  writing  which  are  subject  and
subordinate to the Lien.


                                      -10-
<PAGE>
     "Permitted  Prior  Exceptions"  means (a) general ad valorem real  property
taxes which are not delinquent,  (b) Special Taxes which are not delinquent, and
(c) such  other  matters  as  Lender  shall  expressly  approve  in  writing  as
"Permitted Prior Exceptions" for purposes of this Agreement.

     "Personal   Property"  means  tangible   personal  property  and  Fixtures,
including  building  materials  and supplies,  furnishings,  equipment and other
"Goods"  (as  defined  in  the  Mortgage)  owned  by  Borrower,   but  excluding
construction  equipment  of a type  intended  for use in  connection  with other
projects.

     "Premises" means the Land together with all of the improvements constructed
thereon,  Fixtures and equipment and Personal  Property located thereon and used
in connection with the ownership or operation thereof.

     "Prime" means Prime Group  Realty,  L.P., a limited  partnership  organized
under the laws of the State of Delaware.

     "Prime Rate" means the per annum rate of interest  publicly  announced from
time to time by  Westdeutsche  ImmobilienBank  at Mainz,  Germany  as its "Prime
Rate".

     "Qualified Bank" means with respect to the issuance of any letter of credit
pursuant  to the Loan  Documents,  a  commercial  bank (i) which can issue  such
letter of credit in an amount which, after giving effect to the issuance of such
letter of credit,  does not  exceed the  Agent's  credit  and  country  exposure
limits,  and (ii)  whose  Dollar-denominated  long-term  senior  unsecured  debt
obligations are rated at or above A by Moody's and A by S&P.

     "Qualified Loan" has the meaning set forth in Section 4.2(m).

     "Reinvestment  Rate" shall mean the yield on  actively  traded "On The Run"
United States Treasury  securities having interest payable  semi-annually or the
LIBOR corresponding to the appropriate LIBOR Interest Period, if applicable, and
having a maturity  date  corresponding  to the period from the day preceding the
date of the applicable  prepayment  through (i) the Tenth  Anniversary  Date (if
such  prepayment  is  made  prior  to the  Tenth  Anniversary  Date);  (ii)  the
applicable  LIBOR  Interest  Period  (if  such  prepayment  is made  before  the
conclusion of the selected LIBOR Interest Period) or (iii) the Maturity Date (if
such  prepayment  is made  after  the Tenth  Anniversary  Date) as  reported  by
Bloomberg Financial Markets Commodities News screen USD, provided, however, that
if the Maturity Date is not the same as the maturity date of an actively  traded
"On The Run" United States  Treasury  security,  such yield shall be obtained by
linear interpolation  (calculated to the nearest one-twelfth of a year) from the
yields of actively  traded "On The Run"  Treasury  securities  having a maturity
closest  to the  Maturity  Date  as  reported  by  Bloomberg  Financial  Markets
Commodities  News screen USD or the  equivalent  screen  provided  by  Bloomberg
Financial  Markets  Commodities  News  (or any  nationally  recognized  publicly
available on-line source for similar market data in the United States reasonably
selected by Agent).

     "Rents"  means  all of the  rents,  royalties,  issues,  revenues,  income,
profits and other  benefits now or  hereafter  arising from the Premises and the
Leasehold Premises and the occupancy, use and enjoyment thereof.

     "Rent Roll" has the meaning set forth in Section 3.20 hereof.

     "Repayment Amount" has the meaning set forth in Section 2.7 hereof.

     "Restraint"  means any change  (including  introduction)  after the date of
this Agreement in any applicable law, rule, regulation,  guidelines or directive
including,  without  limitation,  those of the  United  States  and the  Federal


                                      -11-
<PAGE>
Republic of Germany, or the interpretation thereof (having the force of law), by
any governmental authority, central bank or comparable agency, and compliance by
Lenders  with any  request or  directive  (having the force of law) to be issued
after the date of this Agreement of any such authority, bank or agency.

     "Right  of  Others"  means,  as to any  property  in which a Person  has an
interest,  any legal or equitable claim or other interest (other than a Lien but
including a leasehold interest, a right of first refusal in connection with sale
of the  Premises or a right of  repossession  or removal) in or with  respect to
such  property  held by any other  Person,  and any  option or right held by any
other Person to acquire any such claim or other  interest or any Lien in or with
respect to such property.

     "Solvent" and "Solvency"  mean,  with respect to any Person on a particular
date,  that on such date (a) the fair value of the  property  of such  Person is
greater than the total amount of  liabilities,  including,  without  limitation,
contingent  liabilities,  of such Person,  (b) the present fair salable value of
the assets of such  Person is not less than the amount  that will be required to
pay the probable  liability of such Person on its debts as they become  absolute
and  matured,  (c) such Person does not intend to, and does not believe  that it
will, incur debts or liabilities  beyond such Person's ability to pay such debts
and liabilities as they mature and (d) such Person is not engaged in business or
a  transaction,  and is not about to engage in  business or a  transaction,  for
which such Person's property would constitute an unreasonably small capital. For
purposes of this  Agreement,  the amount of contingent  liabilities  at any time
shall  be  computed  as the  amount  that,  in the  light of all the  facts  and
circumstances  existing  at such time,  represents  the amount that is likely to
become an actual or matured liability.

     "Special  Tax" means,  as to any  property,  (a) any special  assessment or
other Tax which is or may  become a Lien  affecting  such  property,  other than
general ad valorem real property  taxes,  and (b) any  assessment,  improvement,
community  facilities  or other  special  taxing  district in or into which such
property  is or may be  located  or  incorporated  or under  which  any  special
assessment or other Tax which is or may become a Lien affecting such property is
or may be imposed.

     "Taxes"  means any and all present or future  taxes,  levies,  impositions,
deductions,  charges or  withholdings  imposed by the United States or any state
thereof (including any political  subdivision or taxing authority thereof),  and
all liabilities with respect thereto; provided,  however, that "Taxes" shall not
include (i) income, gross receipts and similar taxes imposed upon Lenders or any
tax imposed in lieu of and as a direct  substitute  for any such  income,  gross
receipts and similar  taxes and (ii) any taxes levied or assessed in  connection
with a Lender's transfer of all or any part of its interest in the Loan.

     "Tenant" means, as to any Lease, the tenant, lessee,  sublessee or licensee
under such Lease.

     "Tenant  Improvement/Leasing  Commission  Costs" means,  collectively,  all
costs and expenses incurred by Borrower for tenant improvement work, tenant work
allowances or other capital improvements and allowances required pursuant to any
Lease,  and any leasing  commissions  and other costs,  expenses and  allowances
incurred by Borrower in connection  with the leasing of all or a portion of such
tenant improvements pursuant to a Lease.

     "Term"  means the  period  from and  after  the  Closing  Date  until,  and
including,  the Maturity Date or, if  applicable,  the Grace Period  Termination
Date.

     "Title  Company"  means Chicago Title  Insurance  Company and/or such other
title insurance companies as may be reasonably  acceptable to Agent insuring the
priority of the Lien on the Land and the Improvements created by the Mortgage.

                                      -12-
<PAGE>
     "to the best of Borrower's  knowledge" (and similar  expressions)  shall be
construed as meaning to the actual knowledge,  after reasonable due inquiry,  of
Borrower's  Executive Vice President and General Counsel,  or Associate  General
Counsel  after  direct  inquiry of the  building  manager and other  officers of
Borrower  having any relevant  involvement  in the operation of the Premises and
the Leasehold Premises.

     "Trust" means Prime Group Realty Trust,  a Maryland real estate  investment
trust, the managing general partner of Prime.


                                    ARTICLE 2
                                    THE LOAN

     Section 2.1 LOAN.

     The Loan granted under this Agreement  shall be in the aggregate  amount of
ONE HUNDRED SEVENTY MILLION  DOLLARS  ($170,000,000.00)  (the "Loan Amount") and
shall be used for the sole  purpose of the  Borrower  refinancing  the  existing
financing on the Premises.

     Upon  satisfaction  of the conditions  precedent to Lenders'  obligation to
advance the Loan pursuant to this Agreement,  all funds to be advanced hereunder
shall be advanced by each Lender to Agent in the amount set forth  opposite  its
signature on the  signature  page attached  hereto.  Agent and the other Lenders
shall  advance  the Loan  Amount to the Title  Company's  escrow  account on the
Closing Date for payment by  direction of Agent or Agent's  counsel to repay the
existing financing on the Premises,  with any excess proceeds to be disbursed to
Borrower.  The  obligation  of each Lender  under this  Section  2.1(b) shall be
several and not joint.

     Section 2.2 CONDITIONS PRECEDENT.

     The  obligations  of Lenders  hereunder are subject to the  condition  that
Agent shall have  received,  at or prior to the  Closing,  all of the  following
documents in form and substance satisfactory to Agent:

     a  certificate  of  Borrower  signed by a duly  authorized  officer  of the
managing general partner of Borrower, dated as of the Closing Date, stating that
the following statements are true:

          the representations and warranties contained in the Loan Documents are
     correct on and as of the Closing  Date,  before and after giving  effect to
     the making of the Loan by Lenders and to the  application  of the  proceeds
     therefrom, as though made on and as of such date; and

          to the best of Borrower's  knowledge,  no material  event has occurred
     and is  continuing,  or would result from the making of the Loan by Lenders
     or from the  application  of the proceeds  therefrom,  that  constitutes an
     Event of Default;

     certified  copies of the resolutions of the Board of Directors of the Trust
or similar  governing  body, as applicable,  of the general  partner of Borrower
approving  the Loan,  this  Agreement,  the Note and each other Loan Document to
which it is or is to be a party, and of all documents evidencing other necessary
partnership or corporate action and governmental and other third party approvals
and consents,  if any, with respect to the Loan,  this  Agreement,  the Note and
each other Loan Document;

     a copy of the Organizational  Documents of Borrower and the general partner
of Borrower, in each case together with each amendment thereto, and, in the case
of the  certificate of limited  partnership  of Borrower and the  certificate of
incorporation of the general partner of Borrower, certified (as

                                      -13-
<PAGE>
of a date  reasonably  near the Closing  Date) by the  Secretary of State of the
jurisdiction of its formation or  incorporation as being a true and correct copy
thereof;

     a copy of a certificate  of the Secretary of State of the  jurisdiction  of
its  incorporation,  dated  reasonably  near the Closing Date,  certifying  that
Borrower and the general partner of Borrower are duly incorporated or formed and
in good  standing  under  the  laws of the  State of the  jurisdiction  of their
respective organization;

     a copy of a certificate of the Secretary of State of the State of Illinois,
dated  reasonably  near the Closing Date,  stating that Borrower and the general
partner of Borrower are duly qualified and in good standing in such State;

     a  notarized  certificate  of a Secretary  or  Assistant  Secretary  of the
general  partner of Borrower  certifying  the names and true  signatures  of the
officers  of the Trust,  authorized  to sign this  Agreement,  the Note and each
other  Loan  Document  to which  they  are or are to be  parties  and the  other
documents to be delivered hereunder and thereunder;

     in connection with the security interests granted pursuant to the Mortgage:

          copies of financing statements, delivered by Borrower to Title Company
     for filing under the Uniform  Commercial Code of the State of Illinois,  as
     well as any other  jurisdictions  deemed  necessary  or desirable by Agent,
     covering the Collateral and fixtures described in the Mortgage,

          completed  requests  for  information,  dated on or before the Closing
     Date, listing the financing  statements referred to in clause (A) above and
     all  other  effective  financing  statements  filed  in  the  jurisdictions
     referred to in clause (A) above that name Borrower as debtor, together with
     copies of such other financing statements,

          evidence of the  completion of all other  recordings and filings of or
     with respect to the security interest granted pursuant to the Mortgage that
     Agent may deem  necessary  or desirable in order to perfect and protect the
     Liens created thereby, and

          evidence  that  all  other  action  that  Agent  may  deem  reasonably
     necessary or  desirable in order to perfect and protect the first  priority
     liens and security interests created under the Mortgage has been taken;

     the Mortgage in form and substance  satisfactory to Agent and duly executed
by Borrower in recordable form, together with:

          evidence that counterparts of the Mortgage have been duly executed and
     delivered  for recording to the Title Company on or before the Closing Date
     in such form as Agent may deem  necessary or desirable in order to create a
     valid first and subsisting Lien on the property  described therein in favor
     of Agent and that provision has been made for the payment of all filing and
     recording taxes and fees,

          a fully paid Mortgage  Insurance Policy,  in form and substance,  with
     endorsements and in an amount acceptable to, Agent, issued and reinsured by
     the Title Company, insuring the Mortgage to be a valid first and subsisting
     Lien on the Premises and the Leasehold described therein, free and clear of
     all defects  (including,  but not limited to,  mechanics' and materialmen's
     Liens)  and  encumbrances,   excepting  only  Permitted  Encumbrances,  and
     providing for such other affirmative insurance (including  endorsements for
     mechanics' and materialmen's  Liens) and such coinsurance and direct access
     reinsurance as Agent may deem reasonably necessary or desirable,



                                      -14-
<PAGE>
          a survey of the  Premises,  certified  to Agent and the  issuer of the
     Mortgage Insurance Policy in a manner satisfactory to Agent,  acceptable to
     Agent,

          an  Appraisal of the Premises  and the  Leasehold  indicating  an open
     market  value of at least  $243,000,000,  a forced  sale  value of at least
     $170,000,000 and otherwise in form and substance satisfactory to Agent,

          an  engineering  report and such other  reports as Agent has requested
     with respect to the Premises,  in form and substance and from  professional
     firms acceptable to Agent,

          such  consents  and  agreements  of lessors,  if any,  and other third
     parties,  and such estoppel letters and other  confirmations,  as Agent may
     deem reasonably necessary or desirable,

          evidence of the insurance required by the terms of the Mortgage,

          evidence  that  all  other  action  that  Agent  may  deem  reasonably
     necessary or desirable in order to create valid first and subsisting  Liens
     on the Premises and the Leasehold Premises has been taken, and

          original  copies of all mortgage notes being assigned to Agent (or, if
     the same were not available, lost note affidavits, reasonably acceptable to
     Agent with respect thereto), together with all assignments, consolidations,
     splitters,  spreaders,  extensions and modifications thereto, to the extent
     being recorded in connection herewith,  in form for recordation in Chicago,
     Illinois;

     the Environmental Indemnity Agreement, duly executed by Borrower;

     the Cash Collateral Agreement (Central Account), duly executed;

     the Cash Collateral Agreement (Tenant Allowance Reserve), duly executed;

     the Assignment of Contracts and Authorizations, duly executed;

     the Assignment of Leases and Rents, duly executed;

     the Note, duly executed;

     this Agreement, duly executed;

     the Environmental Site Assessment;

     a certified copy of the Management Agreement;

     the Management Subordination Agreement, duly executed;

     a favorable Opinion of Borrower's Counsel;

     copies  of  notices  to be sent  to each  tenant  at the  Premises  and the
Leasehold  Premises  regarding  the  designation  of  Agent  as an  insured/loss
payee/mortgagee in accordance with the Mortgage;

     Subordination,  Non-Disturbance  and Attornment  Agreements with respect to
the Major Tenants, in form and substance acceptable to Agent;

     Estoppel  Certificates (as hereinafter  defined) from (i) R.R.  Donnelley &
Sons,   Inc.,   Everen   Securities,   Inc.  and  Jones  Day,  Reavis  &  Pogue,
Attorneys-at-Law  (the "Major  Tenants")  and (ii) any other  tenants  under the
Leases, demising in the aggregate under clauses (i) and (ii), sixty-six and


                                      -15-
<PAGE>
two-thirds  percent  (66_%) of the  rentable  square  footage  of the  Premises.
Notwithstanding  the  foregoing,   Borrower  will  provide  to  Agent,  Estoppel
Certificates for all tenants for which Borrower received  Estoppel  Certificates
from Seller pursuant to the Purchase  Agreement.  As used in this Agreement,  an
"Estoppel  Certificate"  means an  estoppel  certificate  in form and  substance
acceptable  to Agent which (i) is dated not more than (y)  forty-five  (45) days
prior to the Closing Date with respect to the Major  Tenant,  and (z) sixty (60)
days  prior to the  Closing  Date with  respect to the  balance of the  Estoppel
Certificates.

     financial statements as requested by Agent certified as of the Closing Date
and a certificate of an officer of the Trust stating no material  adverse change
in the  financial  condition of Borrower,  Prime and the Trust has occurred from
the date the financial statements were prepared;

     certified copies of the Leases and Rent Roll;

     payment of Commitment Fee and Arrangement Fee required to be paid hereunder
pursuant to Sections 2.14 and 2.15, respectively; and

     any other  documents  as may  reasonably  be  requested by Agent in Agent's
reasonable discretion.

     Section 2.3 INTEREST.

     During the Term and, if applicable,  the Grace Period,  the Loan shall bear
interest on the outstanding principal amount thereof from time to time at a rate
per annum equal to the Floating Rate.

     During the Term,  Borrower  shall pay to Agent  interest on the Loan on the
last day of each applicable LIBOR Interest Period.

     If applicable, during the Grace Period (if Borrower elects the Grace Period
Option pursuant to Section 2.7 hereof),  Borrower shall pay to Agent interest on
the Loan on the last day of each applicable LIBOR Interest Period.

     All interest on the Loan (including  interest at the Default Rate) shall be
calculated on an actual/360-day basis (including the first day but excluding the
last day).

     Borrower may elect (i) thirty (30),  (ii) sixty (60),  (iii) ninety (90) or
(iv) one hundred and eighty (180) day LIBOR Interest Periods.  In the event that
Borrower fails to so designate the LIBOR Interest Period at least three (3) LIBO
Business Days before the next  succeeding  LIBOR  Interest  Period,  Agent shall
automatically  designate on Borrower's  behalf a ninety (90) day LIBOR  Interest
Period.

     Time shall be of the essence  with respect to the time periods set forth in
this Section 2.3 hereof.

     Section 2.4 THE NOTE.

     The Loan by Lenders to Borrower shall be evidenced by the Note.

     Section 2.5 THE MORTGAGE AND COLLATERAL.

     The Note and all  other  obligations  under  the  Loan  Documents  shall be
secured by the Collateral.  Upon the Closing of this Agreement and the execution
of the Note,  Borrower  will cause the Mortgage to be  registered or recorded in
such a manner and in such a place as may be required in order to publish  notice
of and fully  protect the lien or security  interest of Lenders in the  Premises
and the Leasehold.


                                      -16-
<PAGE>
     Section 2.6 DEFAULT RATE.

     Any overdue principal or interest on the Loan shall bear interest,  payable
upon demand, for each day from and including the date which is one (1) day after
payment  thereof was due but excluding the date of actual  payment at a rate per
annum  equal  to the  lesser  of  the  maximum  interest  rate  permitted  under
applicable  law or a rate  equal to the sum of 3.0%  plus the  Prime  Rate  (the
"Default Rate").

     After the occurrence and during the continuance of an Event of Default, the
Loan shall bear interest at the Default Rate.

     Section 2.7 REPAYMENT OF LOAN.

     The  outstanding  principal  balance  of the Loan shall be repaid in annual
installments  beginning  September  30,  2000 as set forth in Exhibit E (on each
respective date set forth in Exhibit E, each an "Annual  Installment  Payment").
The remaining  outstanding  principal balance and any other indebtedness payable
to Agent or Lenders  under the Loan  Documents  shall be due and  payable on the
Maturity  Date  if no  Grace  Period  is  entered  into or on the  Grace  Period
Termination Date, as the case may be.

     If  Borrower  fails to make any Annual  Installment  Payment on the date on
which such payment is due,  then,  in addition to interest  payable  pursuant to
Section 2.3 or Section 2.6 hereof and  notwithstanding  that  Borrower  may have
exercised  the Grace  Period  Option,  Agent may,  at its option,  withdraw  any
remaining funds from the Cash Collateral Account (Central Account) and apply the
same to amortize all or a portion of the Loan then due and owing.

     Notwithstanding the foregoing,  Borrower may exercise an option (the "Grace
Period  Option")  extending  the Term for the period from and after the Maturity
Date to and including the Grace Period Termination Date (such period, the "Grace
Period") by providing  notice of such  exercise  (the  "Designation  Notice") to
Agent,  on or before the date that is thirty (30) days before the Maturity Date.
A Designation Notice once given shall be irrevocable.  The exercise of the Grace
Period  Option shall only be  available  in the event that no monetary  Event of
Default shall have  occurred and be  continuing or no default of Borrower  under
any material contract instrument or agreement to which Borrower is a party or by
which  Borrower or any of its  properties or assets may be bound or to which any
may be subject,  which  default  might have a material  adverse  effect upon the
business, operations,  properties, assets or conditions (financial or otherwise)
of Borrower  shall have occurred and be  continuing.  The condition set forth in
the  immediately  preceding  sentence must be satisfied on the Maturity Date. In
the event that  Borrower  exercises  the Grace Period  option,  during the Grace
Period  all free cash  flow will be  deposited  in the Cash  Collateral  Account
(Central  Account)  and  will be  governed  pursuant  to  Section  4 of the Cash
Collateral Agreement (Central Account)

     Section 2.8 PREPAYMENTS.

     Borrower  shall  have the option on not less than ten (10)  Business  Days'
prior written notice to Agent to prepay the Loan in whole or in part at any time
and from time to time,  provided,  however,  that any such  prepayment  shall be
accompanied  by accrued  interest on the principal  amount being prepaid to, but
excluding,  the date of such  prepayment  plus the Prepayment  Premium,  if any,
determined  pursuant  to Section 2.9 hereof and any other  amounts  then due and
payable under the Loan Documents.

     In addition to the foregoing, in the event that Borrower prepays all or any
part of the principal amount of the Loan,  Borrower shall also pay the following
amount to Agent (the "Early  Payment  Premium") in addition to any other amounts
required to be paid by Borrower to Agent pursuant to this Section 2.8 in


                                      -17-
<PAGE>
connection  with a prepayment of principal  under the Loan: (i) before or on the
first (1st)  anniversary of the Closing Date,  unless such prepayment is made in
order to avoid  additional  liability  under or pursuant to the  requirements of
Section 2.10 hereof and/or  Section 2.13 hereof,  an amount equal to 2.0% of the
principal  amount so  prepaid;  (ii) after the first  (1st)  anniversary  of the
Closing Date but before or on the fifty-seventh  (57th) month anniversary of the
Closing  Date,  unless  such  prepayment  is made in order  to avoid  additional
liability  under or pursuant to the  requirements of Section 2.10 and/or Section
2.13 hereof,  an amount equal to 1.0% of the  principal  amount so prepaid;  and
(iii)  thereafter,  an amount equal to 0.0% of the principal  amount so prepaid.
Notwithstanding  anything to the contrary herein above set forth, payment of the
Early  Payment  Premium  shall not be required in  connection  with a prepayment
pursuant  to  Sections  2.13 or 8.14  hereof or  Sections  3, 6, 13 or 14 of the
Mortgage.

     Except  for  prepayments  made  pursuant  to  Sections  6 and  3(d)  of the
Mortgage,  any  prepayment  made  pursuant  to this  Section 2.8 must be made in
minimum amount of One Million Dollars  ($1,000,000)  and in One Hundred Thousand
Dollar ($100,000) increments thereafter, for each such prepayment, not including
any Prepayment  Premium or other costs  associated  with such  prepayment  which
shall be in addition to the amount so prepaid.  Prepayment of principal  will be
applied in inverse  order to all  payments  required to be made  hereunder.  Any
amounts prepaid hereunder may not be reborrowed.

     Section 2.9 FUNDING LOSS.

     Borrower   shall   indemnify   Agent  and   Lenders   against  any  actual,
out-of-pocket  third party costs  resulting  solely and directly  from  Borrower
prepaying  (including but not limited to as permitted  under Section 2.8 hereof,
but excluding  scheduled payments of principal pursuant to the Note and payments
deemed made pursuant to Section 8.14 hereof) all or any portion of the principal
of the Loan before the Maturity Date.  For purposes of the foregoing  indemnity,
such loss shall be deemed to be the lesser of (i) the  actual  swap  termination
costs  incurred by Agent (if the Floating  Rate was  determined by Agent through
the  execution  of one or more third  party swap  agreements)  and (ii) any loss
arising from the  reemployment  of funds (such lesser  amount,  the  "Prepayment
Premium").  As used in the  preceding  sentence,  the  "loss  arising  from  the
reemployment  of funds"  shall mean the  excess,  if any,  of (a) the  aggregate
present  value as of the date of such  prepayment  of the sum of (i) each dollar
being  prepaid  and (ii) the  amount  of  interest  at the  Floating  Rate  (but
excluding  the  Applicable  Margin),  that would have been payable in respect of
such Loan amount being prepaid if such prepayment had not been made and the Loan
were repaid in full before the Maturity  Date,  determined by  discounting  such
amounts at a rate equal to the applicable  Reinvestment Rate from the respective
dates from which  they would have been  payable  over (b) the amount of the Loan
being prepaid.  If the applicable  Reinvestment  Rate is equal to or higher than
the Floating Rate  (excluding the  Applicable  Margin),  the Prepayment  Premium
shall be zero. The Prepayment  Premium,  if any, payable by Borrower pursuant to
the terms hereof,  shall include such amount or amounts,  as calculated by Agent
in good faith, as shall  compensate  Agent for any  out-of-pocket  loss, cost or
expense  incurred by Agent for  terminating  or unwinding  any  "forward  swap",
"hedging agreement" or other contractual  arrangement entered into by Agent with
a third party in order to commit to provide the Floating  Rate to be  applicable
for the Grace  Period,  pursuant  to  Section  2.3  hereof.  Agent  will use its
reasonable  best efforts to  mitigate,  to the greatest  extent  possible,  such
losses and expenses by reversing or unwinding any swap,  forward  swap,  hedging
arrangement  or  other  contractual  arrangement  relating  to the  Loan  and/or
reinvesting  any funds paid,  prepaid or deposited by Borrower in a reverse swap
or another  manner so as to reduce or  eliminate  the amount of any such loss or
expense.




                                      -18-
<PAGE>
     A  certificate  of  Agent  prepared  in good  faith  and  setting  forth in
reasonable  detail the basis for the  determination  of any cost and expense and
the  computation  of the  amount  thereof,  shall,  absent  manifest  error,  be
presumptive evidence of such cost and expense and amount.

     All  amounts due under this  Section  2.9 shall be payable by the  Borrower
within ten (10) days of demand by Agent.

     Section 2.10 TAXES.

     Any and all  payments by the  Borrower  under this  Agreement  and the Note
shall be made free and clear of and without deduction for Taxes. If the Borrower
shall be  required  by law to deduct  any Taxes  from or in  respect  of any sum
payable hereunder or under the Note to Agent:

          the sum payable  shall be  increased as may be necessary so that after
     making all required  deductions  (including  but not limited to  deductions
     applicable to additional sums payable under this provision)  Agent receives
     an amount equal to the sum it would have  received  had no such  deductions
     been made; and

          the  Borrower  shall pay to the relevant  taxation  authority or other
     authority the full amount deducted in accordance with applicable law.

     In addition to the payment of Taxes,  the  Borrower  agrees to pay prior to
delinquency all Other Taxes,  which Other Taxes may be repaid in installments if
so permitted under applicable Laws.

     The Borrower  hereby  indemnifies  Lenders for the full amount of Taxes and
Other Taxes on amounts payable under this Section 2.10 which are paid by Lenders
and for any actual liability  (including but not limited to penalties,  interest
and expenses) arising in connection  therewith whether or not such Taxes,  Other
Taxes or liabilities were correctly or legally asserted,  unless due to Lenders'
gross negligence or wilful misconduct.  Agent shall notify Borrower  immediately
after  Agent  learns of such  Taxes,  Other  Taxes or  liabilities,  but Agent's
failure to so notify Borrower shall not limit Borrower's  obligations under this
Section 2.10.  Lenders agree to use their reasonable efforts to minimize amounts
due  hereunder  (including,  without  limitation,  making any  filings  that are
necessary to maintain  Lenders'  respective  exemptions from withholding tax and
assigning  their  respective  interests in the Loan to a branch that is eligible
for such exemption,  provided such efforts are not otherwise  disadvantageous to
the respective  Lenders).  This indemnity shall be fully performed within thirty
(30) days from the date Agent makes written demand therefor.

     Upon  request  by Agent,  within  thirty  (30)  days  after the date of any
payment of Taxes or Other Taxes,  Borrower will furnish to Agent the original or
a certified copy of a receipt or a copy of a check evidencing payment thereof or
other evidence reasonably satisfactory to Agent.

     Without  prejudice  to the  survival  of any other  agreement  of  Borrower
hereunder,  the agreements and obligations of Borrower contained in this Section
2.10 shall survive the  termination of this Agreement and the payment in full of
the Note (subject to applicable statutes of limitation).

     Section 2.11 PAYMENTS.

     All payments of principal,  interest and/or any other amounts in connection
with the Loan are to be made by Borrower  without set-off or counterclaim to the
order of Agent to the account of Agent as from time to time  certified  by Agent
in writing to Borrower in U.S. Dollars in immediately available (same day) funds
not later than 11:00 a.m.  (New York City time) on the date such payment is due.
If any payment would otherwise be due on a day which


                                      -19-
<PAGE>
is not a Business  Day,  then such payment  shall be due on the next  succeeding
Business  Day,  and  interest  shall  accrue up to but not  including  such next
succeeding Business Day. All amounts received hereunder by Agent shall be deemed
received for the benefit of Lenders.

     Borrower  hereby  authorizes  Agent,  if and to the extent  payment  due by
Borrower  under any Loan Document is not made when due under any Loan  Document,
to charge from time to time  against  any and all of  Borrower's  accounts  with
Agent any amount so due.

     Section 2.12 DISTRIBUTION TO LENDERS.

     When Agent receives current funds, in payment of principal, interest or any
other sums due hereunder,  on or prior to 11:00 a.m. (New York City time) on any
Business Day, then, on such date, Agent will notify Lenders of the same and will
distribute  like funds by wire transfer of  immediately  available  funds to the
Lenders  ratably to such accounts at such places as have been  designated by the
respective  Lenders in  writing  from time to time.  If such funds are  received
after  11:00 a.m.  (New York City time) on any  Business  Day,  then Agent shall
distribute  such  funds no later than the next  succeeding  Business  Day.  Upon
Agent's  receipt of any other amounts  payable by Borrower or any other Persons,
for items other than  principal  or  interest,  Agent shall  promptly  cause the
payment to be applied in accordance with this Agreement. Unless Agent shall have
received  notice from Borrower  prior to the date on which any payment is due to
Lenders  hereunder  that Borrower will not make such payment in full,  Agent may
assume  that  Borrower  has made such  payment in full to Agent on such date and
Agent may, in reliance upon such  assumption,  cause to be  distributed  to each
Lender on such due date an amount equal to the amount then due such  Lender.  If
and to the extent Borrower shall not have so made such payment in full to Agent,
each Lender shall repay to Agent  forthwith on demand the portion of such amount
distributed to such Lender for which Agent did not in fact receive  payment from
or on account of Borrower together with interest thereon,  for each day from the
date such amount is  distributed to such Lender until the date such Lender makes
such repayment to Agent, at the Floating Rate.  Borrower shall not be liable for
Agent's failure to make such distributions to Lenders.

     Section 2.13 INCREASED COSTS; OVERRIDING EVENTS.

     In the event of the  imposition  of any Restraint  which shall  prohibit or
restrict  the making or  maintaining  of the Loan or the  charging  of  interest
thereon, Borrower agrees that Agent shall have the right in good faith:

          to comply with any such Restraint and to require the conversion of the
     Floating   Rate  to  an   alternative   interest   rate  (if  available  or
     determinable)  (Agent  shall use its  reasonable  best  efforts  to provide
     Borrower  with a rate of interest  commensurate  to the Floating  Rate or a
     rate of interest consistent with loans and borrowers of a similar type);

          to permit compliance with such Restraint; or

          if an alternative  interest rate is not available or determinable,  to
     require  repayment in full of the outstanding  principal amount of the Loan
     together with accrued interest thereon on the earlier of:

               immediately,  if Lenders  may not  lawfully  continue to fund and
          maintain  the  Loan to  such  day;  provided,  however,  in the  event
          Borrower  cannot make such  immediate  payment,  Borrower  will not be
          required  to pay  interest  at the  Default  Rate for a period  of one
          hundred eighty (180) days from the date of such request by Agent;





                                      -20-
<PAGE>
               sixty (60) days after  written  notice  (notified  by telecopy or
          telex) to  Borrower to repay the Loan in full,  or such longer  period
          (not to exceed one hundred  eighty  (180) days) after the date of such
          written notice as may be reasonably required for Borrower to repay the
          Loan in full.

     In the  event  of the  imposition  of any  Restraint  which  shall  make it
impossible or unlawful for Lenders to give effect to or to maintain any of their
obligations under this Agreement (except as noted in (a) above),  then except as
provided  in  Section  2.13(c)  hereof,  Agent  may give  notice of such fact to
Borrower whereupon Lenders'  obligations  hereunder shall immediately  terminate
and  Borrower  shall,  within  sixty (60) days after  receipt of such notice (or
within  such  shorter  period  as may be  specified  in the  relevant  Restraint
thereof) or such longer period (not to exceed one hundred  eighty (180) days) as
may be  reasonably  required for Borrower to repay the Loan in full) repay Agent
in full the  outstanding  principal  amount of the Loan  together  with  accrued
interest thereon and any other charges due to Lenders  hereunder,  excluding the
Early Prepayment Premium and, in respect of a Restraint based on a change of the
laws of the Federal Republic of Germany, excluding the Prepayment Premuim.

     If a  Restraint  requires  that  any  Lender  transfer  the  Loan  from the
jurisdiction in which it was originally made or then currently held to an office
of such Lender in another jurisdiction and the transfer shall:

          impose,  modify or deem  applicable  any liquidity,  reserve,  capital
     adequacy,  special  deposit or similar  requirement  against any assets of,
     deposits  with or for the  account  of,  or  loans by such  Lender  (or its
     Lending Office), or

          impose on such  Lender (or its Lending  Office)  any other  conditions
     with  respect to this  Agreement  (other than  Taxes,  Other Taxes or other
     liabilities covered by Section 2.10 hereof),

and the result of any of the  foregoing  is to increase  the cost to such Lender
(or its Lending  Office) of giving  effect to the terms of this  Agreement or of
agreeing to make or making,  funding or  maintaining  the Loan,  then in lieu of
Section 2.13(b)  hereof,  upon  notification  of such amount by Agent,  Borrower
shall  either  (i)  promptly  reimburse  Agent  for such  actual,  out-of-pocket
increased costs or (ii) prepay the entire outstanding  principal of the Loan and
any interest accrued thereon (in which event, the Early Prepayment Premium shall
not be due). Lenders shall use their commercially reasonable efforts to minimize
additional  amounts due hereunder  (including,  without  limitation,  making any
filings that are  necessary to minimize or eliminate the effect of the Restraint
and assigning their respective interests in the Loan to a branch or other Lender
to which the Restraint is not applicable).

     A  certificate  prepared  in good  faith  setting  forth  the basis for the
determination  of the facts,  or the increased costs as noted in Subsection (a),
(b) and (c)  immediately  above,  submitted by Agent to Borrower  shall,  absent
manifest error, be presumptive evidence of such actual,  out-of-pocket increased
costs.

     Section 2.14 COMMITMENT FEE.

     Borrower  shall pay to Agent on the Closing Date for the account of Lenders
a  non-refundable  commitment  fee in the amount of EIGHT HUNDRED FIFTY THOUSAND
DOLLARS ($850,000), that being 0.50% of $170,000,000.

     Section 2.15 ARRANGEMENT FEE.

     Borrower shall pay to each of Agent and MCM Consulting Group on the Closing
Date for each of their own  account,  a  non-refundable  arrangement  fee in the
amount of FOUR HUNDRED TWENTY FIVE THOUSAND DOLLARS ($425,000).

                                      -21-
<PAGE>
     Section 2.16 LENDING OFFICE.

     The Loan shall be made by each  Lender  from the office  identified  as its
Lending  Office  hereunder  or from such other  branch or affiliate of each such
Lender as each such Lender may designate to Borrower and Agent in writing as its
Lending Office.

                                    ARTICLE 3
                         REPRESENTATIONS AND WARRANTIES

     Borrower represents and warrants to Lenders, as of the date hereof, that:

     Section 3.1 GOOD STANDING OF BORROWER AND ITS GENERAL PARTNERS.

     Borrower is a limited partnership and is organized and existing and in good
standing  under  the  laws  of  the  State  of  Illinois.  Prime  is  a  limited
partnership,  organized,  existing  and in good  standing  under the laws of the
State of Delaware,  and is qualified to do business in Illinois.  The Trust is a
real estate investment trust, organized, existing and in good standing under the
laws of the State of Maryland.

     Section 3.2 AUTHORITY OF BORROWER.

     Borrower has full power and authority to purchase and own the Premises,  to
enter into this  Agreement,  to make the  borrowings  under this  Agreement,  to
execute and deliver the Loan Documents, and to incur and perform the obligations
provided for in the Loan  Documents,  all of which have been duly  authorized by
all proper and necessary action.  Except for those consents or approvals already
obtained,  no consent or approval of any  Governmental  Authority is required on
the part of Borrower as a condition to the validity or  performance  of any Loan
Documents.

     Section 3.3 AUTHORIZATIONS.

     All  authorizations,  consents,  approvals,  registrations,  exemptions and
licenses  with or from  Governmental  Authorities  which are  necessary  for the
borrowing,  the execution  and delivery of all Loan  Documents,  and  Borrower's
performance  under all Loan  Documents have been effected or obtained and are in
full force and effect.

     Section 3.4 BINDING AGREEMENT.

     The  Note  and  all  other  Loan   Documents  as  executed  and   delivered
concurrently with this Agreement for value received,  constitute,  the valid and
legally  binding  obligations of Borrower  enforceable in accordance  with their
terms, subject only as to enforcement,  bankruptcy,  insolvency,  reorganization
and other laws of general  applicability  relating  to or  affecting  creditors'
rights and to general principles of equity.

     Section 3.5 LITIGATION.

     There are no proceedings or investigations  pending against Borrower or, to
the best  knowledge of Borrower,  threatened  before any court or  arbitrator or
before  or by any  Governmental  Authority  which,  in any  one  case  or in the
aggregate,  if determined  adversely to the  interests of Borrower  would have a
material adverse effect on the business, Premises, Leasehold Premises, condition
(financial or otherwise) or operations of Borrower or its general partner.

     Section 3.6 NO CONFLICTS.

     There is no statute,  regulation, rule, order or judgment, and no provision
of any  mortgage,  deed of trust,  indenture,  contract  or  agreement  to which
Borrower is a party which would  prohibit,  conflict  with or in any way prevent

                                      -22-
<PAGE>
the  execution,  delivery or carrying out of the terms of any Loan  Documents by
Borrower in any material manner.

     Section 3.7 FINANCIAL CONDITIONS.

     The financial  statements  heretofore delivered to Agent fairly present the
financial  condition of Borrower,  as of the dates and for the periods  referred
to, and have been  prepared in accordance  with  Generally  Accepted  Accounting
Principles consistently applied throughout the periods involved. There have been
no material  adverse  changes in the  business,  Premises,  Leasehold  Premises,
condition  (financial  or  otherwise)  or  operations  of  Borrower  which would
materially,  adversely affect Borrower's  ability to comply with its obligations
under the Loan Documents.

     Section 3.8 EMPLOYEE BENEFIT PLANS.

     Borrower (a) is not and will not be an "employee  benefit  plan" as defined
in Section 3(3) of ERISA,  which is subject to Title I of ERISA,  and the assets
of Borrower  do not and will not  constitute  "plan  assets" of one or more such
plans for purposes of Title I of ERISA, and (b) Borrower is not subject to state
statutes  regulating  investments  and  fiduciary  obligations  with  respect to
"governmental plans".

     Section 3.9 GOVERNMENTAL PLAN.

     Borrower is not and will not be a "governmental plan" within the meaning of
Section 3(32) of ERISA and transactions by or with Borrower are not and will not
be subject to state statutes  applicable to Borrower  regulating  investments of
and fiduciary obligations with respect to governmental plans.

     Section 3.10 INVESTMENT COMPANY.

     Borrower is not (i) an "investment  company",  an  "affiliated  person" of,
"promoter"  or  "principal"  underwriter  for or a  company  "controlled"  by an
"investment company",  within the meaning of the Investment Company Act of 1940,
as amended,  (ii) a "holding  company" or a  "subsidiary  company" of a "holding
company"  or an  "affiliate"  of either a  "holding  company"  or a  "subsidiary
company"  within the meaning of the Public Utility  Holding Company Act of 1935,
as  amended,  or (iii)  subject to any other Law that  purports  to  restrict or
regulate  its  ability to borrow  money.  The making and  funding of the Loan by
Lenders,  the application of the proceeds and repayment  thereof by Borrower and
the  consummation  of the  transactions  contemplated  by this Agreement and the
other Loan Documents will not violate any Law,  including,  without  limitation,
any  provision  of such  Acts or any  rule,  regulation  or order  issued by the
Securities and Exchange Commission thereunder.

     Section 3.11 HAZARDOUS MATERIALS.

     Neither  Borrower  nor its  general  partner  is  undertaking,  and has not
completed,  either  individually or together with other potentially  responsible
parties,  any  investigation  or assessment  (other than  investigations  and/or
assessments made in connection with the Environment Site Assessment) or remedial
or response  action relating to any actual or threatened  release,  discharge or
disposal of Hazardous  Materials at the  Premises or the  Leasehold  Premises in
violation of applicable laws, either voluntarily or pursuant to the order of any
Governmental  Authority or the  requirements of any  Environmental  Law; and, to
Borrower's knowledge, all Hazardous Materials generated,  used, treated, handled
or stored at, or transported to or from, the Premises or the Leasehold  Premises
have been disposed of in a manner not reasonably  expected to result in material
liability to Borrower or any of its limited partners.




                                      -23-
<PAGE>
     Section 3.12 SOLVENCY.

     Borrower and its general partner is Solvent.

     Section 3.13 BORROWER'S ADDRESS.

     The location of Borrower's  and its general  partner's  principal  place of
business and chief executive office is as follows:

                  77 West Wacker Drive
                  _ Prime Group Realty Trust
                  77 West Wacker Drive, Suite 3900
                  Chicago, Illinois  60601

                  Prime Group Realty, L.P.
                  77 West Wacker Drive
                  Chicago, Illinois  60601

     Section 3.14 FOREIGN PERSON.

     Neither  Borrower  nor its  general  partners  are a  "foreign  person"  (a
"Foreign Person") within the meaning of ss. 1445(f)(3) of the Code.

     Section 3.15 BANKRUPTCY.

     No  bankruptcy,  reorganization  or insolvency  proceedings  are pending or
contemplated either by Borrower or, to the best of Borrower's knowledge, against
Borrower (or, if Borrower is a partnership or a limited liability  company,  any
of its general partner(s) or managing member(s)).

     Section 3.16 COMPLIANCE WITH LAWS.

     To the best of Borrower's knowledge,  the Premises,  the Leasehold Premises
and the current intended use thereof by Borrower comply in all material respects
with all applicable  restrictive covenants,  zoning ordinances,  subdivision and
building  codes,  flood  disaster  laws,  health and  occupational  laws  having
jurisdiction  over  the  Premises  and  the  Leasehold  Premises.  The  Premises
constitutes  one or  more  separate  tax  parcels  for  purposes  of ad  valorem
taxation.  To the best of Borrower's  knowledge,  the Premises and the Leasehold
Premises do not require any rights over, or restrictions against, other property
in order to comply with any of the  aforesaid  Laws which have not been obtained
and provided to Agent or its counsel for its review and approval.

     Section 3.17 UTILITY SERVICE.

     All utility services  necessary and sufficient for the full use,  occupancy
and  operation  of the Premises and the  Leasehold  Premises for their  intended
purposes  are  available  to  the  Premises  and  the  Leasehold  Premises,   as
applicable,  including water, storm sewer, sanitary sewer, gas, electric,  cable
and telephone  facilities,  through public  rights-of-way  or perpetual  private
easements approved by Agent.

     Section 3.18 ACCESS.

     All streets,  curb cuts and driveways necessary for access to and full use,
occupancy,  operation and disposition of the Premises have been completed,  have
been dedicated to and accepted by the  appropriate  municipal  authority and are
open  and  available  to the  Premises  and  the  Improvements  without  further
condition or cost to Borrower.





                                      -24-
<PAGE>
     Section 3.19 INSURANCE.

     As of the date of this  Agreement,  all insurance  required by the terms of
the  Mortgage  is in full  force and  effect  and none of the  premiums  payable
therefore have been financed.

     Section 3.20 RENT ROLL.

     Borrower  has  delivered  a true,  correct and  complete  schedule (a "Rent
Roll") of all Leases affecting the Premises and the Leasehold Premises as of the
date hereof reasonably  satisfactory to Agent and its counsel, which information
thereon is accurate in respect of each Lease,  and  Borrower  has  delivered  to
Agent and its counsel for its review and  approval  true,  correct and  complete
copies of all Leases described in the Rent Roll.

     Section 3.21 NO RELIANCE ON AGENT OR LENDERS.

     Borrower  is  a  sophisticated  owner,  operator,  developer,  manager  and
investor in real  estate and its  decision to enter into this Loan is based upon
its own independent  expert evaluation of the terms,  covenants,  conditions and
provisions of the Loan  Documents and such other  matters,  materials and market
conditions  and  criteria  which  Borrower  and such  parties  deemed  relevant.
Borrower and its Affiliates have not relied in entering into this Agreement, the
Loan  or the  other  Loan  Documents  upon  any  oral  or  written  information,
representation,   warranty   or   covenant   from   Lenders,   or   any  of  its
representatives,  employees, Affiliates or agents other than the representations
and warranties,  if any, of Lenders  contained  herein.  Borrower,  on behalf of
itself and its  Affiliates,  further  acknowledges  that no  employee,  agent or
representative  of Lenders have been  authorized to make,  and that Borrower and
its Affiliates have not relied upon, any statements, representations, warranties
or covenants  other than those  specifically  contained in this Agreement and in
the other Loan Documents. Without limiting the foregoing,  Borrower acknowledges
that Lenders have made no  representations  or  warranties as to the Loan or the
Premises  (including,  without  limitation,  the cash flow of the Premises,  the
value,  marketability,  condition or future performance  thereof, the existence,
status,  adequacy or sufficiency of the Leases,  the tenancies or occupancies of
the Premises,  or the  sufficiency of the cash flow of the Premises,  to pay all
amounts which may become due from time to time pursuant to the Loan).

                                    ARTICLE 4
                       AFFIRMATIVE AND NEGATIVE COVENANTS

     Section 4.1 AFFIRMATIVE COVENANTS.

     So long as Borrower may borrow  hereunder  and until payment in full of the
Note and all sums borrowed  under this  Agreement and  performance  of all other
obligations of Borrower under this  Agreement and the Loan  Documents,  Borrower
shall do the following:

     Furnish to Agent:

          as soon as  available  but in no event  more than one  hundred  twenty
     (120) days after the close of Borrower's  fiscal year, a copy of the annual
     audit report  relating to Borrower in  reasonable  detail  satisfactory  to
     Agent  and  prepared  in  accordance  with  Generally  Accepted  Accounting
     Principles  by  Ernst  &  Young  or  other  certified   independent  public
     accountants  reasonably  satisfactory  to Agent,  together  with  financial
     statements  consisting of a balance sheet as of the end of such fiscal year
     and statements of income and cash flows of Borrower for such year;





                                      -25-
<PAGE>
          as soon as  available  but in no event  more than one  hundred  twenty
     (120)  days  after the close of the  Trust's  fiscal  years,  a copy of the
     annual  financial  statement  relating to the Trust,  in reasonable  detail
     satisfactory  to Agent and prepared in accordance  with Generally  Accepted
     Accounting  Principles,  together with financial statements consisting of a
     balance  sheet as of the end of such fiscal year and  statements  of income
     and cash flows of the Trust for such year.

          promptly upon receipt  thereof,  copies of any reports and  management
     letters  submitted to Borrower by such  accountants in connection  with any
     annual or interim audit of the books of Borrower;

          within forty-five (45) days after June 30 of each calendar year during
     the term of the Loan,  an updated  Rent Roll,  semi-annual  leasing  status
     reports and unaudited financial statements for the Premises certified by an
     officer of the Trust;

          within  forty-five  (45) days after  December 31 of each calendar year
     during the term of the Loan, an updated Rent Roll and  semi-annual  leasing
     status reports for the Premises certified by an officer of the Trust; and

          such financial, statistical and general information, readily available
     to or producible by Borrower, as Agent may reasonably request.

     Pay all of its  indebtedness as and when the same shall come due,  provided
Borrower  may contest any of the same as long as such contest is pursued in good
faith and with due diligence and does not adversely affect Lenders.

     Satisfy  and  comply  in  all  material   respects  with  all  Governmental
Requirements  applying to and affecting the Premises and the Leasehold  Premises
and shall  obtain and  maintain in full force and effect until the Loan has been
repaid in full all necessary licenses,  permits and similar matters with respect
to the  Premises  and the  Leasehold  Premises,  all without  cost or expense to
Lenders where failure to do so would result in a material  adverse effect on the
business,  Premises,  Leasehold Premises,  condition (financial or otherwise) or
operations  of Borrower,  it being  understood  that Borrower may contest any of
same as long as such contest is pursued in good faith and with due diligence and
does not adversely  affect  Lenders.  Immaterial  violations  which  Borrower is
proceeding  to cure and  which do not  result  in a Lien  being  created  on the
Premises  or the  Leasehold  shall not cause  Borrower  to be in default of this
Section 4.1(c).

     Permit Agent or its  representative  and any Governmental  Authority,  upon
reasonable  notice, to visit and inspect the Premises or the Leasehold  Premises
at any time during  normal  business  hours and at all other  reasonable  times;
provided, however, that all such visits and inspections shall be scheduled so as
to cause minimal disruption to the business and operation of Borrower, Leasehold
Premises and Premises. Agent hereby acknowledges and agrees that all such rights
to visit and inspect are subject to any and all limitations and/or  restrictions
of tenants or other  occupants now or hereafter in the Premises or the Leasehold
Premises.

     Give prompt written notice to Agent of:

          any action or  proceeding  instituted  by or against  Borrower  in any
     court or by any Governmental Authority, or of any such proceedings of which
     Borrower obtains actual knowledge threatened against Borrower, which action
     or  proceeding  may have a  material  adverse  effect  upon  the  business,
     operations,   Premises,  Leasehold,  assets  or  conditions  (financial  or
     otherwise), of Borrower; and




                                      -26-
<PAGE>
          any other  action,  event or condition of any nature known to Borrower
     or of which it should have knowledge which constitutes an Event of Default,
     or a  default  of  Borrower  under  any  material  contract  instrument  or
     agreement to which  Borrower is a party or by which  Borrower or any of its
     properties  or assets  may be bound or to which any may be  subject,  which
     default may have a material  adverse effect upon the business,  operations,
     properties, assets or conditions (financial or otherwise), of Borrower.

     Deliver to Agent all items,  documents,  writings,  reports and information
reasonably required by Agent to consummate the Loan.

     During the term of the Loan,  cause the Debt Service  Coverage  Ratio to be
not  less  than  1.25/1.00  as at any  December  31  (each  such  date,  a "DSCR
Determination  Date").  If, as at any DSCR Determination Date during the term of
the  Loan,  the Debt  Service  Coverage  Ratio is less than as  required  in the
preceding  sentence (any DSCR  Determination Date with respect to which the Debt
Service  Coverage Ratio is less than as required,  a "DSCR Failure  Date"),  the
same shall not  constitute  an Event of  Default  hereunder  if within  five (5)
Business Days after delivery to Agent of the DSCR Financial  Statements relating
to such DSCR  Failure  Date,  Borrower  shall cause all Net Cash Flow and/or any
funds then  available in the Cash  Collateral  Account  (Central  Account) to be
deposited in the Cash Collateral Account (Ratio Reserve), which shall be created
pursuant to the Cash Collateral  Agreement  (Ratio Reserve) then entered into by
Borrower  and  Agent,  until  such time as the DSCR  equals or is  greater  than
1.50/1.00.  Any cash or other collateral  delivered to Agent or deposited in the
Cash  Collateral  Account (Ratio Reserve) in accordance with this Section 4.1(g)
shall  constitute  "Collateral"  for all purposes under this  Agreement.  In the
event that the first sentence of this Section  4.1(g) is breached,  upon request
by Agent,  Borrower shall deliver to Agent,  at Borrower's own cost and expense,
within  sixty  (60)  days of  said  request,  an  M.A.I.  appraisal,  reasonably
satisfactory in form and scope to Agent,  prepared by an appraiser,  selected by
Borrower and reasonably  satisfactory to Agent (an  "Appraisal") of the Premises
and the  Leasehold.  Notwithstanding  and in addition to the  provisions  of the
immediately  preceding sentence,  Agent, at its own cost and expense, may obtain
an Appraisal once each calendar year. The parties hereto  acknowledge  and agree
that no results of an Appraisal  shall alter any right,  liability or obligation
set forth in any Loan Document.

          Concurrently  with the  deposit of any cash or other  collateral  with
     Agent pursuant to Sections 4.1(g) and 4.1(i) hereof,  deliver to Agent such
     agreements and other documents and  instruments  necessary to grant Agent a
     perfected first priority security  interest in such deposits  including but
     not limited to an executed Cash Collateral  Agreement (Ratio Reserve),  and
     Cash Collateral  Agreement  (Tenant Allowance  Reserve).  Any cash or other
     collateral  so deposited  shall be held in an  interest-bearing  account in
     trust  and  applied  by Agent in  accordance  with  the Loan  Documents  as
     security for the payment of any sums due or to become due by Borrower under
     the Loan  Documents.  Upon the  satisfaction  in full of all of  Borrower's
     obligations  under the Loan  Documents and the Debt Service  Coverage Ratio
     being not less than  1.50/1.00  as at any DSCR  Determination  Date without
     regard to the  Collateral  delivered to Agent  pursuant to Section  4.1(g),
     Agent  shall,  within  five (5) days after  receipt by Agent of the written
     request  of  Borrower,  pay or return to  Borrower  the cash or  collateral
     heretofore deposited with any interest accrued thereon.

          In addition to the foregoing, at any time during the term of the Loan,
     Borrower may request that Agent release any cash or  collateral  previously
     delivered to Agent pursuant to Section 4.1(g) hereof (each such request,  a
     "Collateral  Release  Request").  Each Collateral  Release Request shall be
     delivered  to Agent in writing,  together  with (x) a current Rent Roll and
     (y) a projected  cash flow  statement  with respect to the Premises for the
     ensuing 12-month period (which cash flow statement shall reflect any recent


                                      -27-
<PAGE>
     leasing  activity  with  respect to the  Premises),  each  certified  by an
     officer of the Trust,  and (z) any other financial  statements or documents
     reasonably requested by Agent. If, in Agent's reasonable judgment, the Debt
     Service  Coverage  Ratio for the  ensuing  12-month  period is likely to be
     equal to or greater than  1.50/1.00  within five (5) days after  receipt by
     Agent of the applicable  Collateral Release Request,  Agent will release to
     Borrower any cash or collateral  previously  delivered to Agent pursuant to
     Section 4.1(g) hereof.

     Deposit to the Cash Collateral  Account (Tenant Allowance  Reserve) the sum
of $1,500,000 (the "Tenant Allowance Reserve") semi-annually commencing on April
1, 2000 and on the 1st of each  October  and April  thereafter  (each a "Deposit
Date"),  until the Maturity  Date such that,  upon the Maturity  Date,  the Cash
Collateral  Account (Tenant Allowance Reserve) shall have $15,000,000 on deposit
(the "Required Amount");  provided,  however,  that in the event that any of the
Major  Tenants  renews or extends  the term of its  applicable  Lease,  the Cash
Collateral Account (Tenant Allowance Reserve) shall be reduced pro rata, and any
such funds  released  from  escrow  shall  promptly be paid to  Borrower.  As an
alternative to the requirements of the previous  sentence,  Borrower may, at any
time during the term of the Loan,  deposit,  on any Deposit Date,  into the Cash
Collateral  Account (Tenant Allowance  Reserve) an amount not less than $750,000
(any such amount,  a "Deposit  Amount"),  so long as Borrower  also  provides to
Agent (1) an  Acceptable  Letter of Credit  and/or (2) a  Guaranty,  the amounts
represented by the instruments indicated in clauses (1) and (2) of this sentence
to equal not less than the difference between $1,500,000 and the Deposit Amount.
Furthermore,  and subject to the second  sentence  of this  Section  4.1(i),  if
Borrower  exercises the Grace Term Option,  Borrower shall deposit into the Cash
Collateral  Account  (Tenant  Allowance  Reserve)  such sums as are necessary to
provide  the  Required  Amount to be on deposit in the Cash  Collateral  Account
(Tenant Allowance Reserve).  Notwithstanding  anything to the contrary set forth
previously  in this  Section  4.1(i),  Borrower  will have the right to withdraw
funds on deposit in the Cash Collateral  Account (Tenant Allowance  Reserve) for
Tenant Improvement/Leasing Commission Costs in respect of the Major Tenants from
time to time in  accordance  with the  terms of the  Cash  Collateral  Agreement
(Tenant Allowance Reserve) (including,  without limitation, the releasing of any
portion  of  the  Premises   currently  leased  to  a  Major  Tenant)  upon  the
satisfaction of the following terms and conditions:  (i) no Event of Default has
occurred and is  continuing,  and (ii) any amounts so withdrawn  will be applied
only to the payment of Tenant Improvement/Leasing Commission Costs in respect of
the Major  Tenants,  and Borrower  shall have delivered to Agent a duly executed
officer's  certificate  of the Trust  confirming the foregoing and Borrower will
deliver,  or will  have  previously  delivered,  to  Agent  a copy of the  fully
executed  Lease or the amendment to the Lease,  or the final draft  thereof,  to
which such  Tenant  Improvement/Leasing  Commission  Costs  relate  (or, in lieu
thereof,  a summary of the material terms of such lease,  with a full copy to be
delivered  within  thirty  (30)  days).  In the event that  funds are  withdrawn
pursuant to the  immediately  preceding  sentence,  the  security for such funds
shall be released as applicable, in the following order: first, the Guaranty, if
any, and second, the Acceptable Letter of Credit, if any.

     Operate the  Premises  and the  Leasehold at all times as a first class "A"
office building in accordance with all applicable  Laws,  cause the Premises and
the  Leasehold  to be managed  by the  Manager in  accordance,  in all  material
respects, with the terms of the Management Agreement,  perform and cause Manager
to  observe  all the terms and  provisions  of the  Management  Agreement  to be
performed or observed by it in all material  respects,  maintain the  Management
Agreement  in full force and effect and  enforce  the  Management  Agreement  in
accordance with its terms in all material respects,  in each case subject to the
provisions of Section 4.2(h) hereof.  Notwithstanding  the foregoing or anything
in  Section  4.2(h)  hereof,  if  the  Management  Agreement  is  terminated  in
accordance with the terms hereof,  any successor  manager selected  hereunder by
Agent or  Borrower to manage the  Premises  shall be  recognized  in the City of


                                      -28-
<PAGE>
Chicago as a first-class  manager of a stature at least  comparable,  in Agent's
reasonable  judgment,  to the  preceding  Manager,  or a  qualified  (in Agent's
reasonable  judgment)  independent  office building  management company managing
similar  buildings.  Any agreement between Borrower and the new Manager shall be
subject  to  Agent's  prior  written  approval  (which  approval  shall  not  be
unreasonably  withheld,  conditioned  or delayed)  provided  that (a) in Agent's
reasonable  judgment such  agreement is no more favorable to the new Manager and
no less  favorable to Agent than the  Management  Agreement  with the  preceding
Manager;  and (b) the new Manager  enters into an agreement to  subordinate  its
management fees in the same form as the preceding  Manager or in such other form
as Agent shall have approved in Agent's reasonable discretion.

     Pay  and  discharge  before  the  same  shall  become  delinquent,  (i) all
Impositions  imposed  upon or that  become a Lien upon the  Premises;  provided,
however,  that  Borrower  shall not be  required  to pay or  discharge  any such
Imposition that is being  contested in good faith and by proper  proceedings and
as to which  appropriate  reserves are being  maintained in accordance  with the
provisions  of and as  provided  by this  Agreement,  unless  and until any Lien
resulting therefrom attaches to its property and becomes enforceable against its
other creditors and the enforcement  thereof is not stayed pending resolution of
the subject contest.

     Comply,  and require all tenants in accordance with their applicable Leases
and other Persons operating or occupying the Premises or the Leasehold  Premises
to comply, in all material respects,  except as may be permitted by and provided
in this  Agreement,  with all applicable  Environmental  Laws and  Environmental
Permits;   obtain  and  renew  all  Environmental   Permits  necessary  for  its
operations,  the Leasehold Premises and the Premises,  if any, and to the extent
required by any Environmental  Law, conduct any investigation,  study,  sampling
and  testing,  and  undertake  any  cleanup,  removal,  remedial or other action
necessary to remove from the Premises or the Leasehold Premises,  as applicable,
and clean up all Hazardous  Materials which are reasonably expected to result in
material  liability to Borrower,  in  accordance  with the  requirements  of all
Environmental Laws;  provided,  however,  that Borrower shall not be required to
undertake any such cleanup, removal, remedial or other action to the extent that
its  obligation  to do so is  being  contested  in  good  faith  and  by  proper
proceedings and appropriate  reserves are being  maintained with respect to such
circumstances.

     Preserve and maintain its existence,  legal structure,  legal name,  rights
(charter  and  statutory),   permits,   licenses,   approvals,   privileges  and
franchises;  provided,  however, that Borrower shall not be required to preserve
any right, permit, license,  approval,  privilege or franchise if Borrower shall
determine that the preservation thereof is no longer desirable in the conduct of
the business of  Borrower,  as the case may be, and that the loss thereof is not
disadvantageous  in any  material  respect to  Borrower  or  Lenders  and on the
condition that Borrower  notifies Agent in writing of any such change,  promptly
thereafter.

     [Intentionally Omitted]

     To the extent  required by  Environmental  Law,  establish  and maintain an
operations   and   maintenance   program   with  respect  to  any  Asbestos  and
Asbestos-containing Materials located at the Premises or the Leasehold Premises,
which operations and maintenance  program shall comply with all applicable Laws,
conform in all material  respects to applicable  guidelines  established  by any
Governmental  Authority  and  otherwise be designed in all material  respects to
incorporate  all  prudent and  reasonable  safeguards  in order to minimize  any
health risk to patients, residents, employees and guests at the Premises and the
Leasehold  Premises  from  the  presence  of  Asbestos  or   Asbestos-containing
Material.



                                      -29-
<PAGE>
     Maintain or cause to be maintained the Premises and the Leasehold  Premises
in good order,  repair and operating  condition,  ordinary wear and tear and the
occurrence of any casualty or  condemnation  excepted,  make or cause to be made
promptly,  when  necessary,  all  necessary  repairs,  restorations,   renewals,
replacements,   additions  and  improvements  thereto,  interior  and  exterior,
structural and nonstructural, foreseen and unforeseen, or otherwise necessary to
ensure  that the same  shall not in any way be  diminished  or  impaired  in any
material respect, and not cause or knowingly allow the Premises or the Leasehold
Premises to be wasted.

     Keep the Premises and the Leasehold  Premises  equipped as now operated and
will replace all worn out or obsolete equipment in order to maintain and operate
the Premises as a first class "A"  building and comply with all Laws;  provided,
however,  that  Borrower  shall not be  required  to replace  any  equipment  if
Borrower  shall  determine  that  such  replacement  is no longer  necessary  or
desirable   in  the  conduct  of  the   business   of  Borrower   and  that  the
non-replacement  of such  equipment does not adversely  affect,  in any material
respect, Borrower or Lenders.

     Cause all Leases, and all amendments,  renewals and extensions  thereof, to
(i) provide for rental rates and terms which, in Borrower's reasonable judgment,
are  comparable to existing  local market rates and terms,  (ii) be  arms-length
transactions and (iii) be written on the standard form of lease, which is hereby
approved by Agent without material changes  therefrom,  (or, with respect to any
amendment,  renewal  or  extension  of an  existing  Lease,  on the form of such
existing Lease). Upon request, Borrower shall furnish Agent with executed copies
of all Leases (including any amendments or  modifications).  No material changes
may be made to  Agent-approved  standard form of lease without the prior written
consent of Agent, which consent shall not be unreasonably withheld,  conditioned
or  delayed.  Without  Lender's  prior  consent  (which  consent  shall  not  be
unreasonably withheld,  conditioned or delayed), Borrower shall not (i) amend or
terminate  any  Lease  with any  Tenant  whose  Lease or  Leases  demise  in the
aggregate at least 30,000 square  footage of the rentable  square footage of the
Premises,  (ii)  amend or  terminate  any Lease with any Tenant so as to cause a
material adverse effect on the Net Operating Income and (iii) enter into any new
Lease which  demises in the  aggregate  at least  45,000  square  footage of the
rentable  square  footage  of the  Premises.  Within ten (10)  Business  Days of
receipt by Lender of written notification by Borrower to Lender of Lender's need
to provide its consent  pursuant to this Section  4.1(r),  Lender shall  provide
Borrower  with its written  consent,  which  consent  shall not be  unreasonably
withheld,  conditioned or delayed, or objection, and stating the reason for such
objection.  If such consent or objection is not received by Borrower  within the
time  frame  provided  for in the  previous  sentence,  Lender's  consent to the
specific  request shall be deemed granted,  provided that such consent shall not
be deemed granted after the  occurrence and during the  continuance of any Event
of Default.

     Use all  reasonable  efforts  to  obtain,  within  ninety  (90) days of the
Closing Date,  Subordination,  Non-Disturbance  and Attornment  Agreements  (the
"SNDAs") with respect to the Leases from each Tenant in favor of Agent,  in form
and substance acceptable to Agent; provided, however, that a Tenant's failure to
execute an SNDA pursuant to the terms of such Tenant's Lease shall not be deemed
to be a default of Borrower under this Section 4.1(s).

     Now and in the future  remain  Solvent and pay its debts from its assets as
the same shall be due and payable unless such debts are contested by Borrower in
good faith, and such contest is pursued continually and diligently.

     Do,  will do or caused to be done all  things  necessary  to  preserve  its
limited partnership status and/or existence.

     Maintain its books,  records and bank  accounts  separate from those of its
Affiliates and any constituent party.

                                      -30-
<PAGE>
     Be,  and at all times  hold  itself  out to the  public  as a legal  entity
separate  and  distinct  from any  other  entity  (including  any  Affiliate  of
Borrower, any constituent party or any Affiliate of any constituent party).

     Now and in the future maintain its assets in such a manner that it will not
be costly or difficult to segregate, ascertain or identify its individual assets
from those of any constituent  party or any Affiliate of any constituent  party,
or any other Person.

     Except for security  deposits  paid or payable to Borrower by tenants under
the  Lease,  pay or  cause to be paid in the  Lockbox  (as  defined  in the Cash
Collateral  Account (Central  Account)) or the Cash Collateral  Account (Central
Account) all Rents.

     Prior to the date hereof, and from time to time upon the reasonable request
of  Lender,  the  Borrower  shall  deliver  to  Lender,  in form  and  substance
satisfactory to Lender,  such endorsements to the Mortgage  Insurance Policy and
such preliminary  title reports and other title or lien searches  (including UCC
searches) and tax service  contracts as Lender may reasonably  require from time
to time.

     Prior to the date that is thirty  (30) days  after the date  hereof,  cause
there  to be  executed  by an  unrelated  third-party  an  interest  rate  hedge
guaranty,  acceptable  to Agent,  indemnifying  Lenders  against  interest  that
accrues  on the Loan at an annual  rate in excess of 9%.  Until such time as the
guaranty  described in the  immediately  preceding  sentence is in place,  Prime
shall be personally liable for and guaranty to Lenders the interest that accrues
on the Loan at an annual rate in excess of 9%.

     Section 4.2 NEGATIVE COVENANTS.

     Until  payment  in full  of the  Note  and all  sums  borrowed  under  this
Agreement  and  performance  of all other  obligations  of  Borrower  under this
Agreement and the Loan Documents, Borrower shall not do the following:

     Mortgage, pledge, grant or permit to exist a security interest in or a lien
upon any of its assets now owned or hereafter acquired,  without first obtaining
the written  consent of Agent which  consent  cannot be  unreasonably  withheld,
conditioned or delayed;  provided,  however,  that Borrower may contest any Lien
upon on its assets as long as such contest is pursued in good faith and with due
diligence and does not materially adversely affect Lenders.  Notwithstanding the
aforementioned,  Borrower  may enter into such  equipment  financing  contracts,
installment  sales  contracts  and the like in order to finance  the  reasonable
day-to-day equipment needs of Borrower at the Premises.

     Institute or cause to be instituted,  by an issuer or underwriter of, or be
a party to any public  offering with respect to the Premises  within the meaning
of the Securities Act of 1933 and the Securities and Exchange Act of 1934.

     Make  distributions  (other than  distributions to the partners  comprising
Borrower,  as  required  in  Borrower's  partnership  agreement,  and for Income
Taxes),  if the Debt Service  Coverage Ratio for the preceding  calendar year is
less than 1.25/1.00.  Distributions for Income Taxes are expressly  permitted at
all  times.  At any time  that the Debt  Service  Coverage  Ratio is equal to or
greater than 1.25/1.00,  Borrower shall have the right to distribute all amounts
that it has previously  retained  pursuant to the  requirements  of this Section
4.2(c).

     Enter into or suffer to exist any agreement prohibiting or conditioning the
creation or assumption of any Lien upon any of its property or assets other than
in favor of Lenders; provided,  however, that Borrower may contest any such lien
upon on its  property or assets as long as such contest is pursued in good faith
and with due diligence and does not adversely affect Lenders.

                                      -31-
<PAGE>
     Make any material change in the nature of its business as carried on at the
date  hereof or engage in any  business or  activity  other than the  ownership,
operation  and  maintenance  of the Premises  and the  Leasehold  Premises,  and
activities incidental thereto.

     Guarantee  payment of any obligation of any Person or pledge its assets for
the benefit of any third  party,  including  the general  partner,  principal or
Affiliate of Borrower, as the case may be.


     File  or  consent  to the  filing  of any  petition,  either  voluntary  or
involuntary,  to  take  advantage  of  any  applicable  insolvency,  bankruptcy,
liquidation or reorganization  statute, or make an assignment for the benefit of
creditors.

     Without  Agent's prior  consent  (which  consent shall not be  unreasonably
withheld,  conditioned  or  delayed):  (i) cancel or  terminate  the  Management
Agreement or consent to or accept any cancellation or termination thereof except
as permitted  under the JV  Agreement,  (ii) amend or otherwise  modify,  in any
material  respect,  the Management  Agreement,  (iii) waive any material default
under or breach of the Management Agreement,  or (iv) agree in any manner to any
other amendment, modification or change of any material term or condition of the
Management  Agreement,  in  each  case  of  each of  clauses  (i)  through  (iv)
inclusive,  if such action would materially and adversely impair the interest or
rights of Lenders.  Agent's withholding of its consent to a new property manager
shall not be deemed to be unreasonable if the new property  manager,  in Agent's
sole  reasonable  determination,  is  not  a  generally  recognized  manager  of
first-class office buildings in Chicago.

     [Intentionally Omitted]

     Change its Fiscal Year unless such  change  would not  adversely  affect or
alter in any material  respect the  calculation  of Debt Service  Coverage Ratio
pursuant to this Agreement.

     Now or in the future own any  encumbered  asset or property  other than (i)
the Premises and the Leasehold  Premises,  and (ii) incidental personal property
necessary  for the  ownership or  operation  of the  Premises and the  Leasehold
Premises.

     Except as expressly provided in this Agreement, enter into any agreement to
borrow  funds,  including the entering  into of equipment  financing  contracts,
installment sales contracts,  sale-lease back transactions or the like, from any
party  without  the prior  approval  of  Agent.  Notwithstanding  the  preceding
sentence  or other  provision  of this  Agreement  or any other  Loan  Document,
Borrower may, at any time and from time to time without Agent's prior approval:

          Obtain additional  financing  necessary for the reasonable  day-to-day
     operations of the Premises and the  Leasehold;  provided that (A) projected
     Net Cash Flow is  sufficient to repay such amounts when they become due and
     (B) such debt (w) includes customary repayment and amortization  schedules,
     (x) is  unsecured,  (y) is at all  times  subordinated  to the  lien of the
     Mortgage  and (z) cannot be  terminated  and the term  thereof  accelerated
     (other than by  repayment  and  satisfaction  in full of same) prior to the
     repayment and satisfaction in full of the indebtedness  created  hereunder;
     or

          Borrow funds from one or more direct or indirect  partners of Borrower
     and/or any of their respective  Affiliates;  provided that such debt (x) is
     unsecured, (y) is at all times subordinated to the lien of the Mortgage and
     (z) cannot be terminated  and the term thereof  accelerated  (other than by
     repayment  and  satisfaction  in full of same) prior to the  repayment  and
     satisfaction in full of the indebtedness created hereunder.

                                     -32-
<PAGE>
Any  indebtedness  described  in (i) to (ii),  a  "Qualified  Loan".  Except  as
expressly  provided  in this  Agreement,  Borrower  shall not incur any  further
indebtedness  or  other  obligations,  other  than  in the  ordinary  course  of
business, without the prior approval of Agent, which approval Agent may grant or
withhold in its sole discretion.

     Now or in the  future  make  any  loans  or  advances  to any  third  party
(including  any  constituent  party  or  any  affiliate  of  Borrower,   or  any
constituent  party  thereof),  other than  tenants  that are not  Affiliates  of
Borrower in  connection  with Leases  relating to the Premises and the Leasehold
Premises and tenant improvements thereunder.

     Amend, modify or otherwise change the partnership certificate,  partnership
agreement  of  Borrower  in a manner  which would  adversely  affect  Borrower's
existence as a single purpose entity.

     Seek the dissolution or winding up, in whole or in part, of Borrower or any
of its general partners.

     Commingle  the  funds  and  other  assets  of  Borrower  with  those of any
constituent party thereof, any Affiliate, or any constituent party, or any other
Person.

     Now or in the future,  hold itself out to be  responsible  for the debts or
obligations of any other Person.

     Cause, permit or allow the partition of the Premises.

     Without the prior  written  consent of Lender,  which consent or the denial
thereof shall be in Lender's sole and absolute discretion,  make a change in the
Control of Borrower or sell, convey,  alienate,  mortgage,  encumber,  pledge or
otherwise  transfer  all or any  part of the  Premises.  So long as  there is no
change in control of Borrower  in  contravention  of the first  sentence of this
Section 4.2(s),  Borrower, Prime and/or OSTRS, as the case may be, shall each be
permitted  to  transfer  its  direct or  indirect  interests  in  Borrower  to a
Permitted  Transferee,  it  being  understood  that  OSTRS  only  may  become  a
transferee  of an  interest  of Prime or  Borrower  if Agent  has  received  (i)
notification from OSTRS that OSTRS agrees to the provisions set forth in Section
6.1  hereof;  (ii)  an  executed  assumption  agreement,  acceptable  to  Agent,
evidencing  the JV's full  assumption of Borrower's  obligations  under the Loan
Documents;  (iii)  an  executed  copy of the JV  Agreement  and  any  management
agreement that shall supersede the Management  Agreement,  each certified by the
Trust  as being  true  and  complete;  and  (iv) a duly  executed  subordination
agreement substantially in the form of the Management Subordination Agreement.

     Install  or  otherwise  use or  acquire  for  use in  connection  with  the
Collateral  any  Personal  Property  (including  replacement  Personal  Property
pursuant to clause (C) below) which is not owned or leased by Borrower  free and
clear of all Liens  (including  conditional sale contracts) and Rights of Others
(other than Permitted  Exceptions) or which is not a part of the Collateral,  or
(ii) cause or permit the removal from the Premises or the Leasehold  Premises of
any Personal  Property of the Borrower  which is installed or otherwise  used or
acquired for use in connection  with the  Collateral,  except that so long as no
Event of Default  has  occurred  and is  continuing,  this  clause (t) shall not
prohibit  (A) the  temporary  removal of  Personal  Property  for repairs in the
ordinary  course  of  business,   (B)  the  removal  of  Personal   Property  of
insignificant  value which is not  reasonably  necessary or  appropriate  to the
efficient operation of the Premises or the Leasehold  Premises,  as the case may
be, or (C) the removal of  obsolete,  defective  or worn out  Personal  Property
which  has  been  replaced  by other  Personal  Property  of  equal  or  greater
suitability  and value which is intended for the same purpose.  Upon the removal
of any  Personal  Property in  compliance  with  clauses  (B) or (C) above,  the
Borrower  shall be permitted to transfer or otherwise  dispose of such  Personal
Property as the Borrower may determine.
                                      -33-
<PAGE>
                                    ARTICLE 5
                                     DEFAULT

     Section 5.1 EVENTS OF DEFAULT.

     The term "Event of Default" as used  herein  shall mean the  occurrence  or
happening,  at any  time  and  from  time  to  time,  of any  one or more of the
following  which shall  include by  definition  the  expiration of any period of
grace or right to cure provided  therein,  provided there has been satisfied any
requirement in connection  therewith for the giving of notice, lapse of time, or
happening of any further condition, event or act:

     if an Event of Default  occurs under the Mortgage (as defined in Section 22
thereof)  after  expiration  of any  period  of grace or right to cure  provided
therein,  provided  there  has been  satisfied  any  requirement  in  connection
therewith  for the giving of notice,  lapse of time, or happening of any further
condition, event or act;

     if Borrower shall fail to pay any portion of the Debt,  including,  but not
limited to, principal  (including,  without  limitation,  any Annual Installment
Payment),  interest,  fees or other  amounts  payable  to Agent  under  the Loan
Documents within five (5) days after Borrower receives written notice from Agent
that such payment is overdue;

     if Borrower shall fail to comply with the provisions of Sections 4.1(g) and
4.1(h) hereof, within the time periods provided for therein;

     if Borrower fails to duly and promptly  observe,  perform and discharge any
covenant,  term,  condition or agreement contained in the Loan Documents,  other
than any default described in the other paragraphs of this Section 5.1, and such
failure is not curable,  or if curable such  failure  continues  for a period of
thirty (30) days after written notice  thereof from Agent to Borrower,  provided
if such  failure is not  curable in thirty  (30) days  Borrower  shall have such
additional  time as is  reasonably  necessary in the good faith opinion of Agent
after  consultation  with  Borrower  to cure  provided  that  such cure is being
diligently pursued;

     if any  representation or warranty made by Borrower herein or any statement
or  representation  made in any  certificate,  report or  opinion  delivered  in
connection  herewith or in any of the Loan  Documents,  shall prove to have been
incorrect in any material respect on the date as of which made (provided that if
such misrepresentation or breach of warranty is capable of being cured, Borrower
shall have a period of thirty (30) days from the date Borrower  receives written
notice  from Agent or, if such  misrepresentation  or breach of  warranty is not
curable within thirty (30) days,  Borrower shall have such additional time as is
reasonably  necessary in the good faith opinion of Agent after consultation with
Borrower to cure provided that such cure is being diligently pursued); and

     If (i) Borrower shall be in default beyond any notice, grace or cure period
under any other mortgage or security agreement covering any part of the Premises
and the  Leasehold  Premises  whether  it be  superior  or junior in lien to the
Mortgage, or (ii) subject to Borrower's right to contest as provided in the Loan
Documents,  the Premises or the  Leasehold  becomes  subject to any  mechanic's,
materialman's  or other  lien  (except a lien for local  real  estate  taxes and
assessments not then due and payable unless contested by Borrower in good faith,
and such contest is pursued continually and with diligence) and such lien is not
removed within thirty (30) days after Agent delivers notice thereof to Borrower.

     Section 5.2 REMEDIES.

     Upon an Event of Default, Agent may, at its option, use any, some or all of
the following remedies, concurrently or consecutively.


                                      -34-
<PAGE>
     (a) Agent may declare all principal, interest and other amounts outstanding
on  the  Loan  immediately  due  and  payable.   Borrower   expressly  waives  a
presentment, notice, demand and protest of any kind.

     (b) Agent may exercise  any and all of its rights and remedies  provided at
law and under the Note, Mortgage and any other Loan Documents.

     Section 5.3 REMEDIES CUMULATIVE AND CONCURRENT.

     No right,  power or remedy of Agent as provided in this Agreement or in any
of the Loan Documents is intended to be exclusive of any other right,  power, or
remedy  of Agent,  but each and  every  such  right,  power or  remedy  shall be
cumulative and  concurrent  and in addition to any other right,  power or remedy
available  to Agent now or  hereafter  existing  at law or in equity  and may be
pursued  separately,  successively  or  concurrently  at the sole  discretion of
Agent. The failure of Agent to exercise any such right, power or remedy shall in
no event be construed as a waiver or release thereof.

     Section 5.4 WAIVER, DELAY OR OMISSION.

     No waiver of any Event of Default  hereunder  shall extend to or affect any
subsequent  or any other Event of Default then  existing,  or impair any rights,
powers or  remedies  consequent  thereon,  and no delay or  omission of Agent to
exercise  any right,  power or remedy shall be construed to waive any such Event
of Default or to constitute acquiescence therein.

     Section 5.5 INDEMNITY.

     Borrower  hereby  agrees that it will defend,  indemnify  and hold harmless
each  Lender,  and  each  of  its  affiliates,  officers,  directors,  partners,
participants,  employees  and agents  (each,  an  "Indemnified  Party") from and
against,  and shall  reimburse the affected  Indemnified  Party for, any and all
actual,  out-of-pocket  losses,  claims,  damages,  costs,  expenses  (including
reasonable  attorney  fees' and  expenses),  liabilities,  fines,  penalties and
charges arising out of claims made by Persons other than the Indemnified Parties
(collectively,  the "Losses"), which are or may be imposed, or sustained by such
Indemnified Party by reason of (a) ownership of the Mortgage,  the Premises, the
Leasehold  Premises or any interest  therein or receipt of any Rents  therefrom;
(b) any accident, injury to or death of persons or loss of or damage to property
occurring  in, on or about the  Premises,  the  Leasehold  Premises  or any part
thereof or on the  adjoining  sidewalks,  curbs,  adjacent  property or adjacent
parking areas, streets or ways; (c) any use, nonuse or condition in, on or about
the  Premises,  the  Leasehold  Premises  or any part  thereof  or on  adjoining
sidewalks,  curbs, adjacent property or adjacent parking areas, streets or ways;
(d) any  failure on the part of  Borrower  to perform or comply  with any of the
terms of the Loan  Documents;  (e)  performance  of any labor or services or the
furnishing  of any materials or other  property in respect of the Premises,  the
Leasehold  Premises or any part  thereof;  (f) the presence,  disposal,  escape,
seepage, leakage, spillage, discharge,  emission, release, or threatened release
of any Hazardous Substance or Asbestos on, from, or affecting the Premises,  the
Leasehold  Premises or any other property;  (g) any personal  injury  (including
wrongful death) or property damage (real or personal)  arising out of or related
to any  Hazardous  Substance or Asbestos on, from,  or affecting the Premises or
the  Leasehold  Premises;  (h) any  lawsuit  brought or  threatened,  settlement
reached, or government order relating to any Hazardous Substance or Asbestos on,
from, or affecting the Premises or the Leasehold Premises;  (i) any violation of
the  Environmental  Laws,  which are  based  upon or in any way  related  to any
Hazardous  Substance  or Asbestos on,  from,  or  affecting  the Premises or the
Leasehold Premises including,  without limitation, the costs and expenses of any
remedial  action in accordance  with Laws,  reasonable  attorney and  consultant
fees,  investigation and laboratory fees, court costs, and litigation  expenses;
(j) any  failure of the  Premises or the  Leasehold  Premises to comply with any


                                      -35-
<PAGE>
Laws in all material  respects;  (k) any representation or warranty made in this
Loan  Agreement,  the Note, the Mortgage or the other Loan Documents being false
or  misleading  in any material  respect as of the date such  representation  or
warranty was made; (l) any claim by brokers, finders or similar persons claiming
to be entitled to a commission in connection with any Lease or other transaction
involving  the Premises,  the  Leasehold  Premises or any part thereof under any
legal  requirement  or any  liability  asserted  against  Lenders  with  respect
thereto; and (m) the claims of any lessee of all or any portion of the Premises,
the  Leasehold  Premises  or any  person  acting  through or under any lessee or
otherwise  arising under or as a consequence of any Lease,  except to the extent
that (i) such Losses resulted from the gross negligence or willful misconduct of
such Indemnified  Party or (ii) in the case of the foregoing clauses (f) through
(i),  Mortgagor  establishes that such Losses resulted from Hazardous  Materials
being  placed on,  above or under the Premises or the  Leasehold  Premises  only
subsequent to any  foreclosure by Agent or acceptance by Agent of a deed in lieu
of foreclosure with respect to the Premises or the Leasehold  Premises.  In case
any such  claim,  action  or  proceeding  (a  "Claim")  is  brought  against  an
Indemnified  Party in  respect  of which  indemnification  may be sought by such
Indemnified  Party  pursuant  hereto,  Agent  shall give prompt  written  notice
thereof to Borrower, which notice shall include all documents and information in
the  possession  of or under the  control  of Agent and such  Indemnified  Party
relating to such Claim and shall  specifically  state that  indemnification  for
such Claim is being sought under this Section 5.5; provided,  however,  that the
failure  of  Agent  to so  notify  Borrower  shall  not  limit  or  affect  such
Indemnified Party's rights to be indemnified pursuant to this Section 5.5 except
to the extent Borrower is materially prejudiced by such failure. Upon receipt of
such notice of Claim  (together with such documents and  information  from Agent
and such Indemnified  Party),  Borrower shall, at its sole cost and expense,  in
good faith defend any such Claim with counsel  reasonably  satisfactory to Agent
(it being understood that counsel selected by Borrower's insurance carrier shall
be deemed to be acceptable  to Agent and the  Indemnified  Party,  provided such
insurer is an insurer under an insurance policy provided by Borrower pursuant to
the  Loan  Documents  or  otherwise  was  accepted  by Agent  as an  insurer  (a
"Qualified  Insurer")),  which counsel may, without limiting the rights of Agent
and such  Indemnified  Party  pursuant to the next  succeeding  sentence of this
Section  5.5,  also  represent  Borrower  in  such   investigation,   action  or
proceeding. In the alternative,  such Indemnified Party may elect to conduct its
own defense through counsel of its own choosing and at the reasonable expense of
Borrower,  if (A) such Indemnified Party reasonably  determines that the conduct
of its defense by Borrower could be materially prejudicial to its interests, (B)
Borrower  refuses  to  defend,  or (C)  Borrower  shall  have  failed,  in  such
Indemnified  Party's  reasonable  judgment,  to defend  the Claim in good  faith
(unless,  in the case of each of clauses (A),  (B) and (C),  such Claim is being
defended by a Qualified  Insurer).  Borrower  may settle any Claim  against such
Indemnified  Party without such Indemnified  Party's consent,  provided (i) such
settlement  is  without  any  liability,  cost  or  expense  whatsoever  to such
Indemnified Party, (ii) the settlement does not include or require any admission
of liability or culpability by such Indemnified  Party under any federal,  state
or local statute or  regulation,  whether  criminal or civil in nature and (iii)
Borrower obtains an effective  written release of liability for such Indemnified
Party from the party to the Claim with whom such settlement is being made, which
release must be reasonably acceptable to such Indemnified Party, and a dismissal
with  prejudice  with  respect  to all  claims  made by the party  against  such
Indemnified  Party in  connection  with such Claim.  Agent and such  Indemnified
Party shall  reasonably  cooperate  with Borrower,  at Borrower's  sole cost and
expense, in connection with the defense or settlement of any Claim in accordance
with the terms  hereof.  If  Borrower  refuses  to defend  any Claim or fails to
defend such Claim in good faith (other than a Claim that is being  defended by a
Qualified  Insurer)  and such  Indemnified  Party elects to defend such Claim by
counsel of its own choosing,  Borrower shall be  responsible  for any good faith
settlement  of  such  Claim  entered  into by such  Indemnified  Party.  If such
Indemnified  Party  reasonably  determines  that the  conduct of its  defense by


                                      -36-
<PAGE>
Borrower or a Qualified  Insurer  (whichever  is defending  such claim) would be
materially  prejudicial  to its  interests  and  elects to defend  such Claim by
counsel of its own choosing,  Borrower shall be  responsible  for any reasonable
settlement  of such Claim  entered  into by such  Indemnified  Party.  Except as
provided in the preceding two (2)  sentences,  no  Indemnified  Party may pay or
settle any Claim and seek reimbursement therefor under this Section 5.5. Nothing
contained herein shall be construed as requiring Agent or any Indemnified  Party
to expend  funds or incur  costs to  defend  any  Claim in  connection  with the
matters for which Agent or any Indemnified Party is entitled to  indemnification
pursuant to this  Section  5.5.  The  obligations  of Borrower  hereunder  shall
specifically  include the obligation to expend its own funds,  to incur costs in
its own name and to perform all actions as may be necessary to protect  Agent or
any Indemnified  Party from the necessity of expending its own funds,  incurring
cost or  performing  any actions in  connection  with the matters for which each
Lender is entitled to indemnification  hereunder. Any obligation of the Borrower
under clauses (f), (g), (h) and (i) of this Section 5.5 shall terminate upon the
earlier of (i) the tenth (10th)  anniversary  of the conveyance or assignment of
the Premises and the Leasehold  pursuant to a judicial  sale in any  foreclosure
action or by assignment in lieu of foreclosure and (ii) repayment in full of the
outstanding  principal  balance and any other  indebtedness  payable to Agent or
Lenders under the Loan Documents.

                                    ARTICLE 6
                          LIMITED RECOURSE OBLIGATIONS

     Section 6.1 LIMITED RECOURSE.

     Subject to the qualifications  below in this Section 6.1, Lenders shall not
enforce  the  liability  and  obligation  of Borrower to perform and observe the
obligations  contained in the Note,  the  Mortgage,  this Loan  Agreement or the
other Loan  Documents by an action or proceeding  wherein a money judgment shall
be  sought  against  Borrower  or  any  direct  or  indirect  partner,   member,
shareholder,  principal,  director,  employee, officer or affiliate of Borrower,
except  that  Agent may bring a  foreclosure  action,  an  action  for  specific
performance or any other  appropriate  action or proceeding to enable Lenders to
enforce and realize upon the Note, the Mortgage, this Loan Agreement,  the other
Loan Documents, and the interests in the Premises and any other collateral given
to Lenders  pursuant to the Mortgage,  and the other Loan  Documents;  provided,
however, that, except as specifically provided in this Section 6.1, any judgment
in any such action or proceeding  shall be enforceable  against Borrower only to
the extent of  Borrower's  interest in the Premises and in any other  collateral
given to  Lenders.  Agent,  by  accepting  the  Note,  the  Mortgage,  this Loan
Agreement  and the other  Loan  Documents,  and  Lenders,  by  becoming  Lenders
hereunder,  agree  that they shall not sue for,  seek or demand  any  deficiency
judgment   against  Borrower  or  any  direct  or  indirect   partner,   member,
shareholder, principal, director, employee, officer or affiliate of Borrower, in
any such action or  proceeding,  under or by reason of or under or in connection
with the Mortgage,  this Loan  Agreement,  the other Loan Documents or the Note.
The provisions of this paragraph  shall not,  however,  (a) constitute a waiver,
release or  impairment of any  obligation  evidenced or secured by the Mortgage,
this Loan Agreement,  the other Loan Documents or the Note; (b) impair the right
of Agent to name Borrower as a party in any action or suit for  foreclosure  and
sale under the  Mortgage;  (c)  affect the  validity  or  enforceability  of any
guaranty made in connection with the Mortgage, this Loan Agreement,  the Note or
the other  Loan  Documents;  and (d)  impair  the  right of Agent to obtain  the
appointment of a receiver.  Nothing herein shall be deemed to be a waiver of any
right which Agent may have under Section  506(a),  506(b),  1111(b) or any other
provisions  of the U.S.  Bankruptcy  Code to file a claim for the full amount of
the Loan  secured  by the  Mortgage  or to  require  that all  collateral  shall
continue to secure all of the debt owing to Lenders in accordance with the Note,




                                      -37-
<PAGE>
the Mortgage, this Loan Agreement and the other Loan Documents.  Notwithstanding
the foregoing  provisions of this Section 6.1 or any other provision in the Loan
Documents,  Borrower and Prime,  but not any other  direct or indirect  partner,
member,  shareholder,  principal,  director,  employee,  officer or affiliate of
Borrower, shall be fully liable for:

     all actual,  out-of-pocket  losses  suffered and  liabilities  and expenses
incurred  by  Lenders  relating  to fraud or  intentional  misrepresentation  by
Borrower in connection with the loan evidenced by the Loan Documents;

     the physical  waste of the Premises or the Leasehold  Premises by Borrower,
or any failure to  maintain,  repair or restore any part of the  Premises or the
Leasehold  Premises as may be required by the Mortgage,  this Loan  Agreement or
any of the other Loan Documents so as to constitute physical waste;

     the breach of provisions  in the Mortgage  concerning  Environmental  Laws,
Hazardous Substances and Asbestos and any indemnification of Lenders therein;

     the removal or disposal  of any  portion of the  Premises or the  Leasehold
Premises in violation of the terms of the Loan  Documents  after the  occurrence
and during the  continuance of an Event of Default under the Note, the Mortgage,
this Loan Agreement or any other Loan Documents;

     the  misapplication or conversion of Borrower of (i) any insurance proceeds
paid by  reason  of any  loss,  damage or  destruction  to the  Premises  or the
Leasehold Premises, (ii) any awards or other amounts received in connection with
the condemnation of all or a portion of the Premises or the Leasehold  Premises,
or (iii) rents, issues, profits,  proceeds,  accounts, or other amounts received
by  Borrower  after the  occurrence  and during the  continuance  of an Event of
Default  under the Note,  the  Mortgage,  this Loan  Agreement or the other Loan
Documents,  except  when  applied  with the  written  consent of Agent or to pay
Operating  Expenses  incurred  or paid to Agent or  Lenders  as Debt  Service or
otherwise;

     the costs (including reasonable attorneys' fees and disbursements) incurred
by Lenders in connection with the collection or enforcement of the Loan;

     failure to pay Taxes, assessments,  charges for labor or materials or other
charges  that  create  liens on any  portion of the  Premises  or the  Leasehold
Premises for which  Borrower is assessee  unless  contested in good faith,  such
contest being pursued with due diligence and continually;

     any actual,  out-of-pocket  loss, damage,  expense or liability incurred by
Lenders  arising  out of  Borrower's  failure to obtain  Agent's  prior  written
consent to any sale, conveyance,  alienation,  mortgage,  encumbrance, pledge or
other transfer of the Premises or the Leasehold or any part thereof;

     any security  deposits  collected with respect to the Premises that are not
delivered to Agent upon a foreclosure of the Premises or action in lieu thereof,
except to the extent previously applied in accordance with the respective Leases
(as defined in the Mortgage); and

     all of the terms and provisions of the  Environmental  Indemnity  Agreement
and any indemnification of Lenders set forth therein.










                                      -38-
<PAGE>
                                    ARTICLE 7
                                    THE AGENT

     Section 7.1 PERFORMANCE BY AGENT.

     If an Event of Default shall have occurred and be  continuing,  Agent shall
have the right, but not the duty,  without limitation upon any of Agent's rights
pursuant hereto,  to perform in good faith the obligations of Borrower which are
the subject of the Event of Default, in which event Agent shall endeavor to give
notice to Borrower of Agent's performance,  and Borrower agrees to pay to Agent,
within five (5) days of demand  therefor,  all actual and  reasonable  costs and
expenses incurred by Agent in connection therewith, including without limitation
reasonable  attorneys' fees, together with interest from the date of expenditure
at the  Default  Rate,  if an Event of  Default  shall  have  given rise to such
expenditure; provided, however that Borrower shall not be obligated to reimburse
Agent for costs and expenses  incurred by Agent pursuant to this Section 7.1 due
to Agent's gross negligence or willful misconduct. Upon demand by Agent, each of
the Lenders shall promptly  advance to Agent in immediately  available funds its
ratable  portion of the funds  expended by Agent in curing such Event of Default
together  with  interest  thereon at the  Default  Rate from the date of Agent's
payment  through the date prior to the date on which such advance is received by
Agent.  Agent will  disburse to each Lender such  Lenders'  ratable share of any
fees or charges  paid or advanced to Agent by Borrower  (i) pursuant to Sections
2.14 and 8.12 hereof and/or (ii) pursuant to Section 11(c) of the Mortgage.

     Section 7.2 ACTIONS.

     If Agent  shall  have  reasonable  cause to  believe  that  any  action  or
proceeding   related  to  the  Premises  or  the  Leasehold  may,  if  adversely
determined, have a material adverse effect upon the rights or interests of Agent
and/or Lenders under this Agreement or any of the other Loan  Documents,  Agent,
after any applicable notice to Borrower shall have the right to commence, appear
in and defend such action or proceeding,  and in connection  therewith Agent may
pay necessary  expenses,  employ counsel,  and pay reasonable  attorneys'  fees.
Borrower  agrees to pay to Agent,  within five (5) days after demand therefor by
Agent,  all  actual  and  reasonable  costs and  expenses  incurred  by Agent in
connection  therewith,  including without limitation reasonable attorneys' fees,
together with interest from the date of  expenditure  at the Default Rate, if an
Event of Default shall have given rise to such action or proceeding.  Borrower's
obligations to repay such expenses shall be secured by the Loan Documents.

     Section 7.3 NONLIABILITY OF AGENT AND LENDERS.

     Borrower acknowledges and agrees that:

     by  accepting  or approving  anything  required to be observed,  performed,
fulfilled or given to Agent or Lenders pursuant to the Loan Documents, including
any  certificate,  statement  of profit and loss or other  financial  statement,
survey, appraisal, lease or insurance policy, neither Agent nor Lenders shall be
deemed to have warranted or represented the sufficiency, legality, effectiveness
or legal effect of the same, or of any term, provision or condition thereof, and
such  acceptance  or  approval  thereof  shall  not  constitute  a  warranty  or
representation to anyone with respect thereto by Agent;

     neither Agent nor Lenders  undertake nor assume any  responsibility or duty
to Borrower to select, review, inspect,  supervise, pass judgment upon or inform
Borrower of any matter in  connection  with the  Premises or the  Leasehold  and
Borrower shall rely entirely upon its own judgment with respect to such matters,
and any  review,  inspection,  supervision,  exercise  of  judgment or supply of
information  to Borrower by Agent or Lenders in connection  with such matters is
for the  protection  of Agent and/or  Lenders only and neither  Borrower nor any
third party is entitled to rely thereon; and


                                      -39-
<PAGE>
     except to the  extent  caused by a  Lender's  gross  negligence  or willful
misconduct,  neither Agent nor any Lender shall be directly or indirectly liable
or responsible for any loss, claim,  cause of action,  liability,  indebtedness,
damage or injury of any kind or character to any person or property arising from
any  construction  on,  or  occupancy  or use  of,  any of the  Premises  or the
Leasehold  Premises,  including  without  limitation any loss,  claim,  cause of
action,  liability,  indebtedness,  damage or injury caused by, or arising from:
(i) any defect in any building,  structure,  grading, fill, landscaping or other
improvements thereon or in any on-site or off-site improvement or other facility
therein or thereon; (ii) any act or omission of Borrower, the parties comprising
Borrower  or any  of  Borrower's  agents,  employees,  independent  contractors,
licensees or invitees; (iii) any accident in or on the Premises or the Leasehold
Premises  or any  fire,  flood or other  casualty  or hazard  thereon;  (iv) the
failure of Borrower, any of Borrower's licensees,  employees,  invitees, agents,
independent  contractors or other  representatives  to maintain the Premises and
the  Leasehold  Premises  in a safe  condition;  and  (v) any  nuisance  made or
suffered on any part of the Premises or the Leasehold Premises.

     Section 7.4 AUTHORIZATION AND ACTION.

     Each Lender  hereby  appoints and  authorizes  Agent to take such action as
agent on its behalf and to exercise such powers under the Loan  Documents as are
delegated to Agent by the terms hereof and thereof, together with such powers as
are reasonably incidental thereto,  including but not limited to (i) all actions
set forth in Section 59 of the  Mortgage or any similar  provision  of any other
Loan  Document  and (ii)  except  if an  Event of  Default  has  occurred  or is
continuing hereunder, any and all actions related to the Cash Collateral Account
(Central  Account),  Cash  Collateral  Account  (Ratio  Reserve),  if any,  Cash
Collateral  Account  (Tenant  Allowance  Reserve),  if any,  and any other  cash
collateral accounts required to be made hereunder, including but not limited to,
the  release  of monies or other  collateral  deposited  or  delivered  to Agent
pursuant  thereto.  As to any matters  not  expressly  provided  for by the Loan
Documents  (including,  without  limitation,  enforcement  or  collection of the
Note),  Agent  shall not be  required to  exercise  any  discretion  or take any
action,  but shall be  required  to act or to refrain  from acting (and shall be
fully protected in so acting or refraining from acting) upon the instructions of
the Majority Lenders,  and such instructions  shall be binding upon all Lenders;
provided,  however,  that Agent shall not be  required to take any action  which
exposes  Agent to personal  liability or which is contrary to this  Agreement or
applicable law. Agent agrees to give to each Lender prompt notice of each notice
given to it by Borrower pursuant to the terms of the Loan Documents.

     By their execution of this Agreement,  all of the Lenders hereby  delegate,
authorize  and direct Agent to act on their behalf in all respects in connection
with the Loan  Documents and the making of the Loan and agree with Borrower that
Borrower shall only be required to deal with Agent and each of the Lenders shall
be bound by any acts of Agent.

     Except as otherwise  expressly provided in this Agreement,  Agent (i) shall
take all such actions hereunder and under the other Loan Documents which are not
inconsistent  with the terms  hereof or thereof as the  Majority  Lenders  shall
instruct  and (ii) shall not take any  material  actions  hereunder or under the
Loan  Documents  contrary  to the  instructions  of the  Majority  Lenders.  Any
provision of this  Agreement  which grants to Agent the right to make a decision
at its sole  discretion  or in its  reasonable  judgment or at its option or any
other similar  provision is intended,  unless the context shall clearly  require
otherwise,  to apply  only to  relations  between  Borrower  and  Agent  and the
respective  rights and obligations of Borrower and Agent hereunder and shall not
apply to the relations  between Agent and the Lenders or the  respective  rights
and obligations of Agent and the Lenders hereunder.




                                      -40-
<PAGE>
     Promptly after Agent acquires  actual  knowledge  thereof,  Agent will give
written  notice to each Lender of any lien on the  Premises or the  Leasehold or
default under this Agreement or any of the other Loan Documents. Agent agrees to
consult with Lenders in respect of any remedial action to be taken in respect of
any such default and shall act in  accordance  with any decision of the Majority
Lenders.  Agent agrees that during a period of forty-five (45) days from Agent's
notice to Lenders  of any such  default,  Agent will not take any such  material
remedial  action without the prior  agreement of the Majority  Lenders unless in
Agent's good faith judgment it is necessary to take more prompt  remedial action
within such period,  with or without the agreement of the Majority  Lenders,  in
order to preserve  any  collateral  for the  payment of the Loan or  substantive
rights or remedies under any of the Loan  Documents.  Agent shall advise Lenders
from time to time of such remedial action as Agent shall have taken.  All losses
and expenses  incurred by Agent in  connection  with the Loan,  the  enforcement
thereof  or the  realization  of the  security  therefor  shall  be borne by the
Lenders in accordance with their ratable interest in the Loan, and Lenders will,
upon request,  reimburse Agent for their ratable shares of any expenses incurred
by Agent in connection with any such default,  any advances made to pay taxes or
insurance  or  otherwise to preserve the lien of the Mortgage or to preserve and
protect the Premises or the Leasehold (provided,  however,  that Agent shall not
advance  sums in excess of the  principal  amount  of the  Mortgage),  any other
expenses  incurred in connection  with the  enforcement  of the Mortgage and any
expenses  incurred by Agent in connection with the  consummation of the Loan not
paid or provided for by Borrower.

     Agent shall,  in making any Major  Decision,  act upon the direction of the
Majority  Lenders;  provided,  however,  that  without the consent of all of the
Lenders,  Agent shall not,  except as expressly  provided for in Section 7.4(a),
Section 7.4(c) or Section 7.4(d) hereof,  make or consent to any modification of
the Loan or the Loan  Documents,  release any security for the Loan,  or release
any Person from  liability  in  connection  with the Loan under any  guaranty or
otherwise.  As used herein,  "Major Decision" means any decision to exercise any
material  rights or remedies under the Loan  Documents,  or which would alter or
amend the terms of, or security for, the Loan in any material respect  including
the interest rate on the Loan). The provisions of this subsection are solely for
the  benefit  of the  Lenders  and  Agent and shall  not  create  any  rights in
Borrower.

     If Agent shall be  prohibited  by Law from  continuing to act as agent with
respect to the Loan, then, subject to Borrower's  approval (which approval shall
not be  unreasonably  withheld,  conditioned or delayed),  the Majority  Lenders
shall (and at any time may) designate  another Lender to perform the obligations
and exercise the rights of Agent  hereunder.  The  successor  Agent shall assume
such obligations in writing and from and after  Borrower's  receipt of a copy of
notice  of  such  replacement  and  receipt  of a copy of  such  assumption  the
successor  Agent shall be the sole Agent  hereunder  and the term "Agent"  shall
thereafter refer to such successor.

     Section 7.5 WITHHOLDING EXEMPTION CERTIFICATES.

     Concurrently with the disbursement of proceeds of the Loan and concurrently
with (and as a condition precedent to) the sale of any participation interest in
the Loan or assignment of all or any portion of the Loan, Agent shall deliver to
Borrower via facsimile two completed  copies of United States  Internal  Revenue
Service Form 1001 or Form 4224, as applicable, or the successor applicable form,
with  respect to each  Lender  (or,  in the case of any sale of a  participation
interest  or  assignment  of all or any  portion  of the  Loan,  the  applicable
purchaser or assignee) certifying that such Lender (or, if applicable, purchaser
or assignee) is entitled to receive payments under the Loan without deduction or
withholding of any United States federal income taxes. Each Lender shall further
deliver  to  Borrower  two (2)  copies  of such  Form  1001  or  Form  4224,  as
applicable,  or the successor  applicable form, at least thirty (30) days before


                                      -41-
<PAGE>
the date that any such form expires or becomes obsolete or immediately after the
occurrence  of any event  requiring a change in the most recent form  previously
delivered  by it to  Borrower,  in each  case  certifying  that  such  Lender is
entitled to receive payments under the Loan without  deduction or withholding of
any United States federal income taxes.

     Section 7.6 AGENT'S RELIANCE, ETC.

     Agent shall  administer  this  Agreement  and the other Loan  Documents and
service the Loan in accordance  with the terms and  conditions of this Agreement
and with the same  degree  of care as Agent  would  use in  servicing  a loan of
similar size and type held for its own account, provided,  however, that none of
its  directors,  officers,  agents or  employees  shall be liable for any action
taken or  omitted  to be taken by it or them  under or in  connection  with this
Agreement,  except for its or their own gross negligence or willful  misconduct.
Without  limiting the generality of the foregoing,  Agent:  (i) may consult with
legal counsel (including  counsel for Borrower),  independent public accountants
and other  experts  selected  and shall not be liable  for any  action  taken or
omitted  to be taken in good faith by it in  accordance  with the advice of such
counsel, accountants or experts; (ii) makes no warranty or representation to any
Lender and shall not be responsible to any Lender for any statements, warranties
or representations  (whether written or oral) made in or in connection with this
Agreement;  (iii) shall not have any duty to  ascertain  or to inquire as to the
performance  or observance of any of the terms,  covenants or conditions of this
Agreement  on the part of  Borrower  or to  inspect  either  the  Premises,  the
Leasehold or the books and records of Borrower; (iv) shall not be responsible to
any  Lender  for  the  due  execution,   legality,   validity,   enforceability,
genuineness,  sufficiency or value of this Agreement or any other  instrument or
document furnished pursuant hereto; and (v) shall incur no liability under or in
respect of this  Agreement by acting upon any notice,  consent,  certificate  or
other  instrument or writing  (which may be by  telecopier,  telegram,  cable or
telex)  believed by it to be genuine  and signed or sent by the proper  party or
parties.

                                    ARTICLE 8
                                  MISCELLANEOUS

     Section 8.1 FEES AND EXPENSES.

     Borrower  agrees  to  pay  all  actual,  out-of-pocket  expenses  of  Agent
(including the reasonable  fees and expenses of its counsel) in connection  with
the Loan, the  preparation of this Agreement and any amendments or  supplements,
the  enforcement  of  any  provision  of  this  Agreement  or any  amendment  or
supplement and the collection of Note and/or the foreclosure of any Lien, and/or
Mortgage,  and/or  the  enforcement  of this  Agreement  through  all  trial and
appellate  levels,  whether such fees or expenses arise before  proceedings  are
commenced or after entry of a final judgment;  provided,  however, that Borrower
shall not be required to pay more than $10,000 (in total) for Agent's travel and
out-of-pocket expenses incurred in the preparation of the Loan Documents and the
closing of the  contemplated  transaction.  Borrower hereby  authorizes Agent to
utilize  the  proceeds  of the  Loan to  satisfy  any and all of the  costs  and
expenses  referred  to herein and no further  direction  or  authorization  from
Borrower  shall  be  necessary  to  warrant  disbursements  in  payment  of  the
foregoing,  and all such  disbursements  shall earn  interest as provided in the
Note and shall be secured by the Mortgage.

     Section 8.2 CUMULATIVE RIGHTS AND NO WAIVER.

     Each and every  right  granted to Agent  hereunder  or under any other Loan
Documents  delivered hereunder or in connection  herewith,  or allowed by law or
equity, including but not limited to these rights exercisable in connection with
an Event of Default, shall be cumulative and may be exercised from time to time.


                                      -42-
<PAGE>
No failure on the part of Agent to  exercise,  and no delay in  exercising,  any
right will operate as a waiver thereof,  nor will any single or partial exercise
by Agent of any  right  preclude  any other or future  exercise  thereof  or the
exercise of any other right.

     Section 8.3 NOTICES.

     Unless  expressly  contained  herein,  all notices given hereunder shall be
given in accordance with the terms of the Mortgage.

     Section 8.4 SEVERABILITY.

     In case any one or more of the provisions contained in this Agreement shall
be invalid, illegal or unenforceable in any respect under any law, the validity,
legality and enforceability of the remaining  provisions  contained herein shall
not in any way be affected or impaired thereby.

     Section 8.5 BINDING EFFECT.

     This Agreement  shall be binding upon and shall inure to the benefit of the
respective  permitted  successors  and assigns of  Borrower,  Agent and Lenders;
provided,  however,  that  Borrower may not assign any of its rights  hereunder,
except as permitted in this Agreement or in the Loan Documents.

     Section 8.6 EXECUTION IN COUNTERPARTS.

     This  Agreement  may be executed in any number of  counterparts  and by the
different  parties  hereto  on  separate  counterparts,  each of  which  when so
executed and  delivered  shall be an original,  but all the  counterparts  shall
together constitute one and the same instrument.

     Section 8.7 TIME OF THE ESSENCE.

     Time is of the essence in matters pertaining to this Agreement.

     Section 8.8 IMMUNITY.

     Agent's  commitment  to make this Loan  hereunder  shall not at any time be
subject or liable to  attachment or levy at the suit of any creditor of Borrower
or any agent,  contractor,  subcontractor  or  supplier of  Borrower.  All third
parties' rights shall be and are  subordinate and inferior to Lenders'  interest
and lien under the terms of the Mortgage and this  Agreement.  Agent and Lenders
shall not be liable to third parties for services,  labor, materials,  Fixtures,
equipment and other personal property  employed upon,  furnished or delivered to
the Premises or the Leasehold  Premises,  and further as to such third  parties,
Agent shall be under no obligation to adhere to the requirements  herein imposed
as  conditions  for the advance of Loan funds which  requirements  are expressly
intended to be for the sole and exclusive benefit of Agent.

     Section 8.9 GOVERNMENTAL REGULATION OF LENDER.

     Lenders are subject to various Governmental Authorities and the laws, rules
and  regulations  enacted,  adopted and  promulgated by them. To the extent that
Lenders'  power and authority to perform the  obligations on the part of Lenders
to be  performed  under  this  Agreement,  now or  hereafter,  may be limited or
regulated hereby, Lenders are hereby excused from such performance.

     Section 8.10 MODIFICATION, WAIVER, CONSENT.

     Any  modification  or  waiver or any  provision  of this  Agreement  or any
consent to any departure by Borrower therefrom shall not be effective unless the
same is in writing and signed by an authorized  officer of Agent,  and then such


                                      -43-
<PAGE>
modification, waiver or consent shall be effective only in the specific instance
and for the  specific  purpose  given.  Any notice to or demand on Borrower  not
specifically required of Agent hereunder shall not entitle Borrower to any other
or further notice or demand in the same, similar, or other circumstances  unless
specifically required hereunder.

     Section 8.11 ENTIRE AGREEMENT.

     The Loan Documents  contain the entire agreement between the parties hereto
and there are no promises, agreements, conditions, undertakings,  warranties and
representations,  whether  written or oral,  express  or  implied,  between  the
parties hereto other than as set forth in the Loan Documents.

     Moreover,  in the event of a conflict  between  the terms of  another  Loan
Document  and this  Agreement,  the terms of the  document  which  shall  either
enlarge the  interest of Lenders in the  Premises  and the  Leasehold,  grant to
Lenders  greater  financial  security in the Premises and the  Leasehold  and/or
assure repayment by Borrower of all sums due hereunder in full shall control.

     Section 8.12 ASSIGNMENT.

     (a)  Borrower  may  not  assign  this  Agreement  or any of its  rights  or
obligations  hereunder without the prior approval of Agent except as provided in
this Agreement or in the other Loan Documents.

     (b)  Borrower and each Lender  acknowledges  and agrees that Agent may, and
shall  have the right  without  Borrower's  or any  Lender's  consent  to,  sell
participation  interests  in, or to assign,  its  interest  in the Loan,  or any
portion thereof,  subject to Section 7.5 hereof, to any Institution and upon any
assignment  by Agent,  Agent shall be relieved of any  liability  hereunder  and
under any Loan  Document  to the  extent of the  amount so  assigned;  provided,
however,  Agent  shall give ten (10) days  prior  notice of such  assignment  to
Borrower  (together  with a  completed  copy of  Form  1001  or  Form  4224,  as
applicable,  with  respect  to  the  proposed  assignee).   Borrower  and  Agent
acknowledge  that any Lender  (other than Agent) may,  and shall have the right,
subject to Agent's prior written consent, and ten (10) days prior written notice
to  Borrower  (together  with a  completed  copy of Form 1001 or Form  4224,  as
applicable,  with respect to the proposed  assignee) to assign (but not sell any
participation  interests in) its entire interest (but not a portion  thereof) to
any  Institution,  and upon any assignment by such Lender,  such Lender shall be
relieved of any liability hereunder or under any other Loan Document;  provided,
further,  that no such sale or assignment shall result in a material increase in
Borrower's  obligations,  costs or liabilities hereunder or a material reduction
in Borrower's  rights and remedies.  The parties to each such  assignment  shall
execute and deliver to Agent,  for its  acceptance  and recording in the Agent's
Register,  Agent's form of assignment and acceptance agreement,  together with a
processing and recordation fee of $2,500,  which fee shall cover Agent's cost in
connection with the assignments under this Agreement. If an Event of Default has
occurred  and  is   continuing,   Borrower's   consent  to  any   assignment  or
participation  to any party  whatsoever  shall not be  required  and all parties
hereto  agree to  promptly  execute  and  file an  amendment  to this  Agreement
reflecting any such assignment.  Borrower agrees to execute within ten (10) days
after  request  therefor  is  made  by  Agent,  any  documents  and/or  estoppel
certificates reasonably requested by Agent in connection with such participation
or assignment,  without  charge;  provided that such documents  and/or  estoppel
certificates  do not expand the liability or  obligations  of Borrower or reduce
assignee's  or  participant's   obligations  or  reduce  Borrower's  rights  and
remedies.  Upon such  execution,  delivery,  acceptance and recording,  from and
after the effective date specified in such  Assignment and  Acceptance,  (x) the
assignee  thereunder shall be a party thereto and, to the extent that rights and
obligations  hereunder have been assigned to it pursuant to such  Assignment and
Acceptance,  have the rights and  obligations of a Lender  hereunder and (y) the


                                      -44-
<PAGE>
Lender  assignor  thereunder  shall,  to the extent that rights and  obligations
hereunder have been assigned by it pursuant to such  Assignment and  Acceptance,
relinquish its rights and be released from its obligations under this Agreement,
and such  Lender  assignor  shall  cease to be a party  hereto.  The Agent shall
maintain a register (the "Agent's Register") showing the identity of the Lenders
from time to time.

     Section 8.13 APPLICABLE LAW.

     This  Agreement  shall be governed by and construed in accordance  with the
laws of the State of Illinois.

     Section 8.14 USURY.

     Nothing  herein,  nor any transaction  related hereto or thereto,  shall be
construed or so operate as to require Borrower to pay interest at a greater rate
than is lawful under  applicable  law. Should any interest or other charges paid
by  Borrower  in  connection  with all  advances  made to  Borrower  under  this
Agreement  result in the  computation  or earning of  interest  in excess of the
maximum lawful rate of interest which is legally permitted under applicable law,
then any and all such excess shall be, and the same is hereby,  waived by Agent,
and any and all such excess shall be, at Agent's option, be returned to Borrower
or credited against and in reduction of the balance due under the  indebtedness,
and the portion of such excess which exceed the balance due under this Agreement
and the  Note  evidencing  the  indebtedness,  shall  be  returned  by  Agent to
Borrower.

     Section 8.15 CONSENT TO JURISDICTION.

     Borrower, Agent and Lenders each hereby irrevocably submit to the exclusive
jurisdiction  and  venue of any  state or  federal  court  sitting  in  Chicago,
Illinois for the purpose of any suit, action, proceeding or judgment relating to
or arising out of this  Agreement  or the Note or the  Mortgage  and/or the Loan
Document.

Section 8.16 MONIES.

     All references to monies in this  Agreement  shall be deemed to mean lawful
monies of the United States of America.

     Section 8.17 JURY TRIAL.

     AGENT,  LENDERS AND BORROWER HEREBY KNOWINGLY AND  INTENTIONALLY  WAIVE THE
RIGHT  EITHER  MAY HAVE TO A TRIAL BY JURY IN RESPECT  TO ANY  LITIGATION  BASED
HEREON,  OR ARISING OUT OF, UNDER OR IN CONNECTION WITH THIS AGREEMENT,  AND ANY
AGREEMENT  CONTEMPLATED TO BE EXECUTED IN CONNECTION HEREWITH,  OR ANY COURSE OF
CONDUCT, COURSE OF DEALING, STATEMENTS (WHETHER VERBAL OR WRITTEN) OR ACTIONS OF
EITHER PARTY.  THIS  PROVISION IS A MATERIAL  INDUCEMENT  FOR LENDERS  EXTENDING
CREDIT TO BORROWER.  FURTHER,  BORROWER, HEREBY CERTIFIES THAT NO REPRESENTATIVE
OR AGENT OF AGENT, NOR AGENT'S COUNSEL, HAS REPRESENTED, EXPRESSLY OR OTHERWISE,
THAT AGENT  WOULD NOT,  IN THE EVENT OF SUCH  LITIGATION,  SEEK TO ENFORCE  THIS
WAIVER OF RIGHT TO JURY TRIAL PROVISION.

                            [SIGNATURES ON NEXT PAGE]










                                      -45-
<PAGE>
     IN WITNESS  WHEREOF,  this Agreement was executed and delivered the day and
year first above written.

                                       BORROWER:

                                       77 WEST WACKER LIMITED PARTNERSHIP

                                       By:  Prime Group Realty L.P., its general
                                            partner


         By:  Prime Group Realty Trust, its managing general partner

                                             By:   /s/ Jeffrey A. Patterson
                                                --------------------------------
                                                Name:  Jeffrey A. Patterson
                                                       -------------------------
                                                Title: Executive Vice President
                                                       -------------------------



                                       For purposes of Sections 4.1(aa) and 6.1
                                       hereof only:

                                       PRIME GROUP REALTY, L.P.


                                       By:  Prime Group Realty Trust, its
                                            managing general partner

                                            By:/s/ Jeffrey A. Patterson
                                               ---------------------------------
                                            Name:  Jeffrey A. Patterson
                                                   -----------------------------
                                            Title: Executive Vice President
                                                   -----------------------------


                       [SIGNATURES CONTINUED ON NEXT PAGE]
























                                      -46-
<PAGE>
                                       AGENT AND LENDER:

                                       WESTDEUTSCHE IMMOBILIENBANK

MAXIMUM US$125,000,000                 By:   /s/ Armin Gemmerich
                                           -------------------------------------
                                          Name:  Armin Gemmerich
                                                 -------------------------------
                                          Title: Vice President
                                                 -------------------------------

                                       By:   /s/ Andreas Schwab
                                           -------------------------------------
                                          Name:  Andreas Schwab
                                                --------------------------------
                                          Title: Assistant Vice President
                                                --------------------------------

                                       LENDER:

                                       LANDESBANK SCHLESWIG-HOLSTEIN

US$[27,500,000]                        By:   /s/ Benno Mokwinski
                                           -------------------------------------
                                          Name:  Benno Mokwinski
                                                --------------------------------
                                          Title: Executive Vice President
                                                --------------------------------

                                       By:   /s/ Ursula Kemphausen
                                           -------------------------------------
                                          Name:  Ursula Kemphausen
                                                --------------------------------
                                          Title: Senior Vice President
                                                --------------------------------

                                       LENDER:

                                       LANDESBANK SAAR GIROZENTRALE

US$[25,000,000]                        By:   /s/ Hans Porter
                                             -----------------------------------
                                          Name:  Hans Porter
                                                --------------------------------
                                          Title: Vice President
                                                --------------------------------

                                       By:   /s/ Dirk Hoffmann
                                           -------------------------------------
                                          Name:  Dirk Hoffmann
                                                --------------------------------
                                          Title: Vice President
                                                --------------------------------











                                      -47-
<PAGE>
                                       LENDER:

                                       DSL BANK

US$[20,000,000]                        By:     /s/ H. Willemse
                                             -----------------------------------
                                          Name:    H. Willemse
                                                --------------------------------
                                          Title: Senior Vice President
                                                --------------------------------

                                       By:   /s/ R. Fuchs
                                           -------------------------------------
                                          Name:  R. Fuchs
                                                --------------------------------
                                          Title: FVP
                                                --------------------------------















































                                      -48-
<PAGE>
                                    EXHIBIT A

                    Cash Collateral Agreement (Ratio Reserve)
                    -----------------------------------------




                             Intentionally Deleted























































                                      -49-
<PAGE>
                                    EXHIBIT B

                               Description of Land
                               -------------------





                             Intentionally Deleted






















































                                      -50-
<PAGE>
                                    EXHIBIT C

                                     Leases
                                     ------



                             Intentionally Deleted
























































                                      -51-
<PAGE>
                                    EXHIBIT D

                             Permitted Encumbrances
                             ----------------------

All those  encumbrances  set forth on Schedule B to that certain title policy of
Chicago  Title  Insurance  Company dated as of the date hereof,  No.  007822406,
covering 77 West Wacker Drive, Chicago, Illinois.
























































                                      -52-
<PAGE>
                                    EXHIBIT E

                          Principal Repayment Schedule
                          ----------------------------


September 30, 2000                                          $4,000.000
September 30, 2001                                          $4,000.000
September 30, 2002                                          $4,500.000
September 30, 2003                                          $5,000.000
September 30, 2004                                          $5,000.000





















































                                      -53-

<TABLE>
                                                                                                                        EXHIBIT 12.1

                                                              PRIME GROUP REALTY TRUST AND THE PREDECESSOR
                                                         STATEMENTS REGARDING COMPUTATION OF RATIOS OF EARNINGS
                                                       TO COMBINED FIXED CHARGES AND PREFERRED SHARE DISTRIBUTIONS
                                                                          (Dollars in Thousands)
<CAPTION>
                                                                   Prime Group Realty Trust - Historical
                                          ---------------------------------------------------------------------------------------
                                                                                                                        Period
                                                                                                                         from
                                                                                                                     November 17,
                                              Three months ended            Nine months ended           Year             1997
                                                September 30,                 September 30,             ended          through
                                          ---------------------------   ---------------------------   December 31,   December 31,
                                              1999           1998           1999           1998           1998           1997
                                          ------------   ------------   ------------   ------------   ------------   ------------
<S>                                       <C>            <C>            <C>            <C>            <C>            <C>
Earnings:
  Income before preferred share
    distributions and minority
    interests per the consolidated
    financial statements............      $     56,029   $      9,688   $     79,013   $     21,195   $     30,866   $      1,427
  Interest expense..................            10,899          7,615         32,822         22,091         30,901          1,680
  Amortization of debt issuance
    costs...........................               646            422          1,739          1,061          1,230            140
                                          ------------   ------------   ------------   ------------   ------------   ------------
Earnings............................      $     67,574   $     17,725   $    113,574   $     44,347   $     62,997   $      3,247
                                          ============   ============   ============   ============   ============   ============

Fixed charges:
  Interest expense..................      $     10,899   $      7,615   $     32,822   $     22,091   $     30,901   $      1,680
  Capitalization of interest
    expense.........................             2,519            958          5,513          1,422          2,498              -
  Amortization of debt issuance
    costs...........................               646            422          1,739          1,061          1,230            140
  Preferred share distributions.....             3,037          2,950          9,067          4,991          7,971            345
                                          ------------   ------------   ------------   ------------   ------------   ------------
Total fixed charges.................      $     17,101   $     11,945   $     49,141   $     29,565   $     42,600   $      2,165
                                          ============   ============   ============   ============   ============   ============

Ratio of earnings to combined
  fixed charges and preferred
  share distributions...............              3.95           1.48           2.31           1.50           1.48           1.50
                                          ============   ============   ============   ============   ============   ============

Excess of earnings to combined
  fixed charges and preferred
  share distributions...............      $     50,473   $      5,780   $     64,433   $     14,782   $     20,397   $      1,082
                                          ============   ============   ============   ============   ============   ============

Funds from operations:
   Funds from operations............      $     13,904   $     12,600   $     41,188    $    33,858   $     46,762   $      3,619
   Interest expense.................            10,899          7,615         32,822         22,091         30,901          1,680
   Amortization of debt issuance
     costs..........................               646            422          1,739          1,061          1,230            140
   Preferred share distributions....             3,037          2,950          9,067          4,991          7,971            345
                                          ------------   ------------   ------------   ------------   ------------   ------------
Adjusted funds from operations......      $     28,486   $     23,587   $     84,816   $     62,001   $     86,864   $      5,784
                                          ============   ============   ============   ============   ============   ============
Fixed charges:
   Interest expense.................      $     10,899   $      7,615   $     32,822   $     22,091   $     30,901   $      1,680
   Capitalization of interest
     expense........................             2,519            958          5,513          1,422          2,498              -
   Amortization of debt issuance
     costs..........................               646            422          1,739          1,061          1,230            140
   Preferred share distributions....             3,037          2,950          9,067          4,991          7,971            345
                                          ------------   ------------   ------------   ------------   ------------   ------------
Total fixed charges.................      $     17,101   $     11,945   $     49,141   $     29,565   $     42,600   $      2,165
                                          ============   ============   ============   ============   ============   ============

Ratio of funds from operations to
  combined fixed charges and
  preferred share distributions.....              1.67           1.97           1.73           2.10           2.04           2.67
                                          ============   ============   ============   ============   ============   ============

Excess of funds from operations to
  combined fixed charges and
  preferred share distributions.....      $     11,385   $     11,642   $     35,675   $     32,436   $     44,264   $      3,619
                                          ============   ============   ============   ============   ============   ============
</TABLE>
                                      -1-
<PAGE>
<TABLE>
                                            PRIME GROUP REALTY TRUST AND THE PREDECESSOR
                                       STATEMENTS REGARDING COMPUTATION OF RATIOS OF EARNINGS
                                      TO COMBINED FIXED CHARGES AND PREFERRED SHARE DISTRIBUTIONS
                                                          (Dollars in Thousands)
<CAPTION>
                                                          Predecessor - Historical
                                          ---------------------------------------------------------
                                           Period from
                                           January 1,
                                          1997, through           Year ended December 31,
                                          November 16,   ------------------------------------------
                                              1997           1996           1995           1994
                                          ------------   ------------   ------------   ------------
<S>                                       <C>            <C>            <C>            <C>
Earnings:
  Loss before preferred share
    distributions and minority
    interests per the combined
    financial statements............      $    (29,050)  $    (31,417)  $    (29,576)  $    (22,062)
  Interest expense..................            34,417         37,217         36,234         33,387
  Amortization of debt issuance
    costs...........................               630            594          1,148            714
                                          ------------   ------------   ------------   ------------
Earnings                                  $      5,997   $      6,394   $      7,806   $     12,039
                                          ============   ============   ============   ============

Fixed charges:
  Interest expense..................      $     34,417   $    37,217    $     36,234   $     33,387
  Capitalization of interest
    expense.........................                 -             -               -              -
  Amortization of debt issuance
    costs...........................               630           594           1,148            714
  Preferred share distributions.....                 -             -               -              -
                                          ------------   ------------   ------------   ------------
Total fixed charges.................      $     35,047   $     37,811   $     37,382   $     34,101
                                          ============   ============   ============   ============

Ratio of earnings to combined fixed
  charges and preferred share
  distributions.....................                 -              -              -              -
                                          ============   ============   ============   ============

Deficit of earnings to combined
  fixed charges and preferred
  share distributions...............      $    (29,050)  $    (31,417)  $    (29,576)  $    (22,062)
                                          ============   ============   ============   ============

Funds from operations:
  Funds from operations.............      $    (14,461)  $    (17,367)  $    (12,733)  $    (12,930)
  Interest expense..................            34,417         37,217         36,234         33,387
  Amortization of debt issuance
    costs...........................               630            594          1,148            714
  Preferred share distributions.....                 -              -              -              -
                                          ------------   ------------   ------------   ------------
Adjusted funds from operations......      $     20,586   $     20,444   $     24,649   $     21,171
                                          ============   ============   ============   ============

Fixed charges:
  Interest expense..................      $     34,417   $     37,217   $     36,234   $     33,387
  Capitalization of interest
    expense.........................                 -              -              -              -
  Amortization of debt issuance
    costs...........................               630            594          1,148            714
  Preferred share distributions.....                 -              -              -              -
                                          ------------   ------------   ------------   ------------
Total fixed charges                       $     35,047   $     37,811   $     37,382   $     34,101
                                          ============   ============   ============   ============

Ratio of funds from operations to
  combined fixed charges and
  preferred share distributions.....                 -              -              -              -
                                          ============   ============   ============   ============

Deficit of funds from operations to
  combined fixed charges and
  preferred share distributions.....      $    (14,461)  $    (17,367)  $    (12,733)  $    (12,930)
                                          ============   ============   ============   ============
</TABLE>
                                      -2-

<TABLE> <S> <C>

<ARTICLE>                     5
<MULTIPLIER>                  1,000

<S>                                    <C>
<PERIOD-TYPE>                          YEAR
<FISCAL-YEAR-END>                      DEC-31-1999
<PERIOD-START>                         JAN-01-1999
<PERIOD-END>                           SEP-30-1999
<CASH>                                          10,173
<SECURITIES>                                         0
<RECEIVABLES>                                  104,107
<ALLOWANCES>                                         0
<INVENTORY>                                    162,716  <F1>
<CURRENT-ASSETS>                                     0
<PP&E>                                         990,886
<DEPRECIATION>                                 (31,572)
<TOTAL-ASSETS>                               1,236,310
<CURRENT-LIABILITIES>                          256,726  <F2>
<BONDS>                                        643,267
                                0
                                         40
<COMMON>                                           151
<OTHER-SE>                                     336,126
<TOTAL-LIABILITY-AND-EQUITY>                 1,236,310
<SALES>                                              0
<TOTAL-REVENUES>                               204,269
<CGS>                                                0
<TOTAL-COSTS>                                        0
<OTHER-EXPENSES>                               120,276  <F3>
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                              32,822
<INCOME-PRETAX>                                 50,342
<INCOME-TAX>                                         0
<INCOME-CONTINUING>                                  0
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                   (829)
<CHANGES>                                            0
<NET-INCOME>                                    50,342
<EPS-BASIC>                                     2.73
<EPS-DILUTED>                                     2.72
<FN>
<F1>  Amount includes restricted cash escrows ($118,052), net deferred costs
      ($22,985), and other assets ($21,679).
<F2>  Amount includes accrued interest payable ($2,610), accrued real estate
      taxes ($36,814), accounts payable and accrued expenses ($27,678),
      liabilities for leases assumed ($3,242), dividends payable ($8,104), other
      liabilities ($8,409) and minority interests of ($169,869).
<F3>  Amount includes property operations ($33,205), real estate taxes
      ($26,370), depreciation and amortization ($25,382), loss on land
      development option ($600), general and administrative expense ($5,472) and
      minority interests allocation ($29,247).
</FN>


</TABLE>


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