CORNERSTONE PROPERTIES INC
10-Q, 1998-11-16
REAL ESTATE
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<PAGE>

- --------------------------------------------------------------------------------
- --------------------------------------------------------------------------------

                                    FORM 10-Q

                       Securities and Exchange Commission
                              Washington, DC 20549

/x/     Quarterly report pursuant to Section 13 or 15(d) of the
        Securities Exchange Act of 1934 for the quarterly period ended 
        September 30, 1998

                                       or

/ /     Transition report pursuant to Section 13 or 15(d) of the
        Securities Exchange Act of 1934 for the transition period from _________
        to_________

                         Commission File Number 0-10421
                                   -----------
                           CORNERSTONE PROPERTIES INC.
             (Exact name of Registrant as specified in its Charter)

             Nevada                                     74-2170858
(State or other jurisdiction of                (IRS Employer Identification No.)
incorporation and organization)


                              126 East 56th Street
                               New York, New York
                    (Address of principal executive offices)

                                      10022
                                   (Zip Code)

                                 (212) 605-7100
              (Registrant's telephone number, including area code)

Securities registered pursuant to Section 12(b) of the Act:
<TABLE>
<CAPTION>

  Title of each class:              Name of Each Exchange on which Registered:
  --------------------              ------------------------------------------
<S>                                 <C>
  Common Stock, no par value        New York Stock Exchange
                                    Dusseldorf Stock Exchange
                                    Frankfurt Stock Exchange

</TABLE>

     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 
                                             -----     ------

     Aggregate market value of registrant's voting Common Stock held by
non-affiliates as of November 12, 1998: $1,518,230,531.

Number of shares of Common Stock outstanding as of November 12, 1998: 
101,638,864.

<PAGE>

                                    PART I - FINANCIAL INFORMATION
Item 1. Financial Statements

                              CORNERSTONE PROPERTIES INC. AND SUBSIDIARIES
                                 CONDENSED CONSOLIDATED BALANCE SHEETS
                         (Dollar amounts in thousands, except per share amounts)

<TABLE>
<CAPTION>


                                                                                September 30,       December 31,
                                                                                    1998               1997
                                                                                -------------       ------------
                                                                                 (Unaudited)
<S>                                                                             <C>               <C>        
ASSETS

Investments, at cost:
       Land                                                                     $   315,498       $   260,542
       Buildings, leasehold interests and improvements                            1,854,308         1,559,085
       Investment in real estate joint venture                                      245,784           240,253
       Deferred lease costs                                                         140,638           127,645
                                                                                -----------       -----------
                                                                                  2,556,228         2,187,525
       Less: Accumulated depreciation and amortization                              271,218           229,652
                                                                                -----------       -----------
          Total investments                                                       2,285,010         1,957,873

Cash and cash equivalents                                                            30,566            24,730
Restricted cash                                                                       5,250             1,903
Other deferred costs, net of accumulated amortization of $3,015 and $1,998          145,726             5,728
Deferred tenant receivables                                                          48,352            38,531
Tenant and other receivables, net                                                    10,026             7,584
Notes receivable                                                                        528             1,652
Other assets                                                                         10,120            13,480
                                                                                -----------       -----------
Total Assets                                                                    $ 2,535,578       $ 2,051,481
                                                                                -----------       -----------
                                                                                -----------       -----------
LIABILITIES

Long-term debt, inclusive of $11,799 and $11,209 of unamortized premium         $   849,554       $   706,178
Credit facility                                                                     148,000           187,000
Accrued interest payable                                                              7,261             4,134
Accrued real estate taxes payable                                                    19,446            13,401
Accounts payable and accrued expenses                                                19,841            18,363
Unearned revenue and other liabilities                                               16,770            10,986
                                                                                -----------       -----------
Total Liabilities                                                                 1,060,872           940,062
                                                                                -----------       -----------

MINORITY INTEREST

Minority Interest in operating partnership                                           55,258              --
Minority Interest in real estate joint ventures                                      14,811            15,420
                                                                                -----------       -----------
Total Minority Interest                                                              70,069            15,420


Commitments and Contingencies

Redeemable Preferred Stock; 344,828 shares authorized;
   0 shares issued and outstanding                                                     --                --

STOCKHOLDERS' INVESTMENT
7% Cumulative Convertible Preferred Stock, $16.50 stated value;
   65,000,000 shares authorized; 3,030,303 shares issued and outstanding             50,000            50,000
Common stock, no par value; 250,000,000 shares authorized;
   (1998-101,636,864; 1997-83,191,819) shares issued and outstanding
Paid-in capital                                                                   1,356,615         1,048,187
Deferred compensation                                                                (1,978)           (2,188)
                                                                                -----------       -----------
Total Stockholders' Investment                                                    1,404,637         1,095,999
                                                                                -----------       -----------
Total Liabilities and Stockholders' Investment                                  $ 2,535,578       $ 2,051,481
                                                                                -----------       -----------
                                                                               -----------       -----------
</TABLE>

                          The accompanying notes are an integral part of these
                              condensed consolidated financial statements.

                                                 2 of 30
<PAGE>

Item 1. Financial Statements (continued)

                          CORNERSTONE PROPERTIES INC. AND SUBSIDIARIES
                           CONDENSED CONSOLIDATED STATEMENTS OF INCOME
                 FOR THE THREE AND NINE MONTHS ENDED SEPTEMBER 30, 1998 AND 1997
                     (Dollar amounts in thousands, except per share amounts)
                                           (Unaudited)

<TABLE>
<CAPTION>
                                                        Three Months     Three Months     Nine Months      Nine Months
                                                           Ended            Ended            Ended            Ended
                                                        September 30,    September 30,    September 30,    September 30,
                                                           1998             1997             1998             1997
                                                        -------------    -------------    -------------    -------------
<S>                                                     <C>              <C>              <C>              <C>      
Revenues
       Office and parking rentals                       $  83,227        $  34,546        $ 239,767        $ 103,237
       Earnings in real estate joint venture                3,856             --             10,150             --
       Interest and other income                            1,955            3,868            7,167            8,432
                                                        ---------        ---------        ---------        ---------
           Total Revenues                                  89,038           38,414          257,084          111,669
                                                        ---------        ---------        ---------        ---------

Expenses
       Building operating expenses                         18,896            7,660           52,947           22,693
       Real estate taxes                                   12,034            5,933           34,900           17,553
       Interest expense                                    16,057            7,405           47,724           22,395
       Depreciation and amortization                       15,702            7,057           42,561           20,865
       General and administrative                           3,169            1,869            8,713            5,134
                                                        ---------        ---------        ---------        ---------
           Total Expenses                                  65,858           29,924          186,845           88,640
                                                        ---------        ---------        ---------        ---------
                                                           23,180            8,490           70,239           23,029
                                                        ---------        ---------        ---------        ---------
Other income (expenses)
      Loss on sale of real estate assets                     (127)            --             (2,324)            --
      Minority interest                                    (1,826)            (414)          (4,682)          (1,408)
      Net gain on interest rate swaps                        --               --               --                 99
                                                        ---------        ---------        ---------        ---------
Income before extraordinary item                           21,227            8,076           63,233           21,720

Extraordinary loss                                         (2,269)            --             (2,269)             (54)
                                                        ---------        ---------        ---------        ---------

Net income                                              $  18,958        $   8,076        $  60,964        $  21,666
                                                        ---------        ---------        ---------        ---------
                                                        ---------        ---------        ---------        ---------
Income applicable to preferred stock                    $    (875)       $    (875)       $  (2,625)       $  (9,285)
                                                        ---------        ---------        ---------        ---------
                                                        ---------        ---------        ---------        ---------
Income applicable to common stock                       $  18,083        $   7,201        $  58,339        $  12,381
                                                        ---------        ---------        ---------        ---------
                                                        ---------        ---------        ---------        ---------
Income before extraordinary item per common share       $    0.20        $    0.16        $    0.62        $    0.37
                                                        ---------        ---------        ---------        ---------
                                                        ---------        ---------        ---------        ---------
Extraordinary loss per common share                     $   (0.02)       $    --          $   (0.02)       $    --
                                                        ---------        ---------        ---------        ---------
                                                        ---------        ---------        ---------        ---------
Basic income per common share                           $    0.18        $    0.16        $    0.59        $    0.37
                                                        ---------        ---------        ---------        ---------
                                                        ---------        ---------        ---------        ---------
Diluted income per common share                         $    0.18        $    0.16        $    0.59        $    0.37
                                                        ---------        ---------        ---------        ---------
                                                        ---------        ---------        ---------        ---------

</TABLE>
                           The accompanying notes are an integral part of these
                               condensed consolidated financial statements.

                                                 3 of 30
<PAGE>

Item 1. Financial Statements (continued)

                                CORNERSTONE PROPERTIES INC. AND SUBSIDIARIES
                              CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS
                           FOR THE NINE MONTHS ENDED SEPTEMBER 30, 1998 AND 1997
                                        (Dollar amounts in thousands)
                                                 (Unaudited)
<TABLE>
<CAPTION>
                                                                                         Nine Months       Nine Months
                                                                                            Ended             Ended
                                                                                        September 30,     September 30,
                                                                                            1998              1997
                                                                                          ---------         ---------
<S>                                                                                      <C>               <C>      
Cash flows from operating activities:
        Net income                                                                        $  60,964         $  21,666
        Adjustments to reconcile net income to net cash
           provided by operating activities:
              Depreciation and amortization                                                  42,618            21,282
              Deferred compensation amortization                                                787               661
              Share of net loss in real estate joint venture                                  5,001              --
              Net gain on interest rate swap                                                   --                 (99)
              Extraordinary loss                                                              2,269                54
              Unbilled rental revenue                                                        (9,332)             (978)
              Increase in accrued interest payable                                            3,127               440
              Minority interest share of income                                               4,682             1,408
              Loss on sale of real estate assets                                              2,324              --
              Increase in tenant and other receivables and other assets                      (3,777)           (4,772)
              Increase in accounts payable, accrued expenses and other liabilities            8,123             3,810
                                                                                          ---------         ---------

              Total adjustments                                                              55,822            21,806
                                                                                          ---------         ---------

              Net cash provided by operating activities                                     116,786            43,472
                                                                                          ---------         ---------

Cash flows from investing activities:
        Additions to investment property                                                   (343,160)          (75,064)
        Repayment of notes receivable                                                         1,124               903
        Investments in and advances to real estate joint ventures                            (7,134)             --
        Proceeds from sale of real estate assets                                             45,538              --
                                                                                          ---------         ---------

              Net cash used in investing activities                                        (303,632)          (74,161)
                                                                                          ---------         ---------

Cash flows from financing activities:
        Proceeds from common stock offering                                                 262,344           225,400
        Borrowings under mortgage loans                                                      82,377            35,000
        Borrowings under credit facility                                                    221,500              --
        Repayments under credit facility                                                   (260,500)             --
        Repayment of term loan                                                                 --             (32,500)
        Repayments under mortgage loans                                                      (2,502)             (812)
        Proceeds from dividend reinvestment plan                                              5,247             8,586
        Net payments for swap terminations and debt prepayment costs                         (1,762)             (216)
        Increase in restricted cash                                                          (3,348)          (35,302)
        Stock and debt issuance costs                                                       (15,610)          (18,139)
        Distributions to minority partners                                                   (5,618)           (1,285)
        Distributions to preferred stockholders                                              (3,500)          (10,160)
        Distributions to common stockholders                                                (85,946)          (29,812)
                                                                                          ---------         ---------

              Net cash provided by financing activities                                     192,682           140,760
                                                                                          ---------         ---------

Increase in cash and cash equivalents                                                         5,836           110,071
Cash and cash equivalents, beginning of period                                               24,730           114,803
                                                                                          ---------         ---------
Cash and cash equivalents, end of period                                                  $  30,566         $ 224,874
                                                                                          ---------         ---------
                                                                                          ---------         ---------
</TABLE>
                            The accompanying notes are an integral part of these
                                condensed consolidated financial statements.

                                                  4 of 30
<PAGE>


Item 1.  Financial Statements (continued)

                  CORNERSTONE PROPERTIES INC. AND SUBSIDIARIES
              NOTES TO CONDENSED CONSOLIDATED FINANCIAL STATEMENTS
                               SEPTEMBER 30, 1998


1.   NATURE OF COMPANY'S BUSINESS AND SIGNIFICANT ACCOUNTING POLICIES

Nature of the Company's Business

     Cornerstone Properties Inc., a Nevada corporation ("Cornerstone" or the 
"Company"), is a self-advised real estate investment trust ("REIT") that owns 
interests in 21 Class A office properties comprising approximately 11.4 
million rentable square feet that are located in 11 metropolitan areas 
throughout the United States. Cornerstone's strategy is to own interests in 
Class A office properties in prime central business district locations and 
major suburban office markets in U.S. metropolitan areas. Class A office 
properties are generally considered to be those that have the most favorable 
locations and physical attributes, command premium rents and experience the 
highest tenant retention rates within their markets.

     In January 1998, Cornerstone converted its corporate structure into an 
umbrella limited partnership REIT ("UPREIT"). Under the UPREIT structure, 
Cornerstone owns all of its properties and conducts all of its property 
business through Cornerstone Properties Limited Partnership, a Delaware 
limited partnership (the "Operating Partnership"), of which Cornerstone is 
the sole general partner. As of November 12, 1998, Cornerstone owned, 
directly or indirectly, approximately 96.1% of the common units of 
partnership interest ("UPREIT Units") in the Operating Partnership.

General

     The condensed consolidated financial statements included herein have 
been prepared by the Company, without audit, pursuant to the rules and 
regulations of the Securities and Exchange Commission. Certain information 
and footnote disclosures normally included in consolidated financial 
statements prepared in accordance with generally accepted accounting 
principles have been omitted pursuant to such rules and regulations, although 
the Company believes that the disclosures are adequate to make the 
information presented not misleading. In the opinion of management of the 
Company, all adjustments, consisting only of normal recurring accruals 
necessary to summarize fairly the unaudited results of operations for the 
three and nine month periods presented, have been included. Results for the 
three and nine months ended September 30, 1998 are not necessarily indicative 
of results which may be expected for any other interim periods or for the 
year as a whole. It is suggested that these condensed consolidated financial 
statements be read in conjunction with the audited financial statements and 
notes thereto included in the Company's latest annual report on Form 10-K.

Principles of Consolidation

     The accompanying financial statements include the accounts of 
Cornerstone, its wholly-owned qualified REIT subsidiary, the Operating 
Partnership and controlled partnerships. The Company has consolidated the 
following partnerships because it has a majority interest in the economic 
benefits and is or has the right to become the managing general partner at 
its sole discretion: NWC Limited Partnership ("NWC"); Third and University 
Limited Partnership ("Third Partnership"); Two Twenty Two Berkeley Venture 
("222 Berkeley"); Five Hundred Boylston West Venture ("500 Boylston") and One 
Ninety One Peachtree Associates ("191 Peachtree"). All significant 
intercompany balances and transactions have been eliminated in consolidation.

Reclassifications

     The Company has reclassified certain prior period amounts in order to 
conform them to the September 30, 1998 financial statement presentation.

                                     5 of 30
<PAGE>

Minority Interest

     Minority interest in the Operating Partnership relates to the interest 
in the Operating Partnership the Company does not own, which as of September 
30, 1998 amounted to 3.9%. The Company allocates income to the minority 
interest in the Operating Partnership based on the weighted-average 
percentage ownership in the Operating Partnership through the year. Persons 
who contributed assets to the Operating Partnership received UPREIT Units, 
shares of Cornerstone's common stock (the "Common Stock"), cash or a 
combination thereof. At the request of a Unitholder, the Company will be 
obligated to redeem each UPREIT Unit held by such Unitholder for one share of 
Common Stock or, at the option of the Company, cash equal to the fair market 
value of one share of Common Stock at the time of redemption. Such 
redemptions will cause the Company's percentage ownership in the Operating 
Partnership to increase. As of September 30, 1998, the number of issued and 
outstanding UPREIT Units held by Unitholders other than the Company was 
4,145,883 (3.9%) and as of such date, no UPREIT Units have been exchanged for 
shares of Common Stock.

     Minority interest in real estate joint ventures represents the Company's 
partner's capital account balances in NWC, Third Partnership, 222 Berkeley, 
500 Boylston and 191 Peachtree. Debit balances in certain of these capital 
accounts originated through special cash distributions in excess of the 
partner's share of income in accordance with certain provisions of the 
respective partnership agreements. Realizability of the debit balances is 
continually monitored by calculating pro forma sales proceeds under the 
respective partnership agreements.

Recently Issued Accounting Standards

     During 1998, the Financial Accounting Standards Board issued Statement 
of Financial Accounting Standard No. 133 "Accounting for Derivative 
Instruments and Hedging Activities" ("SFAS 133"), which is effective for 
fiscal years beginning after June 15, 1999. SFAS 133 establishes a new model 
for accounting for derivatives and hedging activities and supersedes and 
amends a number of existing standards. In addition, the Accounting Standards 
Executive Committee of the American Institute of Certified Public Accountants 
issued Statement of Position 98-5, "Reporting on the Costs of Start-Up 
Activities" ("SOP 98-5") and Statement of Position 98-1, "Accounting for the 
Costs of Computer Software Developed or Obtained for Internal Use" ("SOP 
98-1"), which are effective for fiscal years beginning after December 15, 
1998. SOP 98-5 requires that certain costs incurred in conjunction with 
start-up and organizational activities be expensed. SOP 98-1 provides 
guidance on whether the costs of computer software developed or obtained for 
internal use should be capitalized or expensed. Management believes that when 
the Company adopts SFAS 133, SOP 98-5 and SOP 98-1 they will not have a 
significant impact on the Company's financial statements.

     During the first quarter of 1998, the Company adopted the Emerging 
Issues Task Force of the Financial Accounting Standards Board release Issue 
No. 97-11, "Accounting for Internal Costs Relating to Real Estate Property 
Acquisitions" ("EITF 97-11"). EITF 97-11 requires that the internal 
pre-acquisition costs of identifying and acquiring operating property be 
expensed as incurred. The adoption of EITF 97-11 did not have a material 
impact on the Company's financial statements.

     During the first quarter of 1998, the Company also adopted the Financial 
Accounting Standards Board's Statement of Financial Accounting Standard No. 
130, "Reporting Comprehensive Income" ("SFAS 130"). SFAS 130 specifies the 
presentation and disclosure requirements for comprehensive income which 
includes those items which have been formerly reported as a component of 
stockholders' equity. The adoption of SFAS 130 did not have a significant 
impact on the Company's financial statements.

Estimates and Risks

     The preparation of 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 to 
make disclosure of contingent assets and liabilities at the date of the 
financial statements and the reported amounts of revenues and expenses during 
the reporting period. The most significant risks, estimates and assumptions 
are related to the recoverability and depreciable lives of investment 
property, the recoverability of deferred tenant receivables and the 
qualification of the Company as a REIT. Actual results could differ from 
those estimates.

                                    6 of 30
<PAGE>

2. PROPERTIES

     The following table summarizes Cornerstone's interest in real estate
investments at September 30, 1998:

<TABLE>
<CAPTION>

                                                                   Completed/   Net Rentable              Ownership
Property                               Location                     Acquired    square feet    % Leased    Interest   Notes
- --------                               --------                     --------    ----------     --------    --------   -----
<S>                            <C>                             <C>              <C>           <C>         <C>         <C> 
One Norwest Center..........   Denver, Colorado                        1983      1,188,000          97%       100%
Norwest Center..............   Minneapolis, Minnesota                  1988      1,118,000          99%        50%        A
Washington Mutual Tower.....   Seattle, Washington                     1988      1,155,000          99%        50%        B
125 Summer Street...........   Boston, Massachusetts              1989/1995        464,000          99%       100%
Tower 56....................   New York, New York                 1983/1996        162,000          99%       100%        C
One Lincoln Centre..........   Oakbrook Terrace, Illinois         1986/1996        297,000          91%       100%
527 Madison Avenue..........   New York, New York                 1986/1997        216,000         100%       100%
191 Peachtree Street........   Atlanta, Georgia                   1991/1997      1,221,000          97%        80%        D
Market Square...............   Washington, D.C.                   1990/1997        689,000          95%        59%        E
500 Boylston Street.........   Boston, Massachusetts              1988/1997        715,000         100%      91.5%        F
222 Berkeley Street.........   Boston, Massachusetts              1991/1997        531,000         100%      91.5%        F
Charlotte Plaza.............   Charlotte, North Carolina          1982/1997        613,000          98%       100%
200 Galleria................   Atlanta, Georgia                   1985/1997        433,000          94%       100%
11 Canal Center.............   Alexandria, Virginia               1986/1997         70,000          96%       100%
99 Canal Center.............   Alexandria, Virginia               1986/1997        138,000          99%       100%
TransPotomac Plaza 5........   Alexandria, Virginia               1983/1997         96,000         100%       100%
Sixty State Street..........   Boston, Massachusetts              1979/1997        823,000          99%       100%        G
Corporate 500 Centre........   Deerfield, Illinois             1986-90/1998        679,000          95%       100%        H
One Memorial Drive..........   Cambridge, Massachusetts           1987/1998        353,000         100%       100%        I
201 California Street.......   San Francisco, California          1980/1998        240,000         100%       100%        J
Wilshire Palisades..........   Santa Monica, California           1981/1998        186,000         100%       100%        J


</TABLE>

- --------
(A)  While the Company's stated interest in the partnership that owns Norwest
     Center is 50%, its economic interest in the property is significantly
     larger due to priority distributions it receives on its invested capital
     base. For the nine months ended September 30, 1998, the Company's share of
     earnings and cash distributions from the partnership that owns Norwest
     Center was 81%.

(B)  While the Company's stated interest in the partnership that owns Washington
     Mutual Tower is 50%, its economic interest in the property is significantly
     larger due to priority distributions it receives on its invested capital
     base. For the nine months ended September 30, 1998, the Company received
     100% of the cash distributions from the partnership that owns Washington
     Mutual Tower.

(C)  On January 5, 1998, the Company purchased the remaining participation
     rights in the cash flow and residual value of Tower 56 from the former
     participants for 307,692 shares of Common Stock. As a result, all cash flow
     and the residual value of Tower 56 inures to the Company.

                                     7 of 30
<PAGE>

(D)  While the Company's stated interest in the partnership that owns 191
     Peachtree Street is 80%, its economic interest is significantly larger
     because it acquired the first mortgage note on the property in the
     amount of $145 million, which earns interest at 9.375% and will receive a
     priority distribution on its acquired capital base. In 1997, the partner in
     the transaction, CH Associates, Ltd., received an annual incentive
     distribution of $250,000, which the Company expects it will continue to
     receive under the partnership agreement through February 28, 2000, with the
     Company receiving the remainder of the cash flow from the property.

     The partnership that owns 191 Peachtree Street leases a portion of the 
     land upon which the project is located pursuant to a ground lease 
     agreement. The agreement requires the partnership to make annual 
     payments of $5,000 through January 31, 1998, $45,000 through January 31, 
     2002 and $75,000 through January 31, 2008. Thereafter, the annual rent 
     increases $2,500 per year until the expiration date of January 31, 2087. 
     The partnership records ground rental expense relating to this agreement 
     on a straight-line basis. The ground lease is renewable for an 
     additional 99 years.

(E)  In January 1998, the Company acquired partnership interests with a stated
     interest of approximately 59% in the partnerships that own Market Square,
     with the option to purchase an additional 1%. The Company's economic
     interest is significantly larger because it has acquired the first mortgage
     note on the property in the amount of $181.0 million, which earns interest
     at 9.75% and will receive a priority distribution on its acquired capital
     base. In addition, the Company acquired a "buffer loan", with accrued
     principal and interest of $49.0 million, which accrues interest at a rate
     of 11% per annum and is payable from cash flow, refinancing or sales
     proceeds from Market Square in excess of the first mortgage. During the
     nine months ended September 30, 1998, the Company received 100% of the cash
     flow from the property. The Company accounts for the transaction as an
     equity investment in real estate.

(F)  Distributions of cash flow and sales and refinancing proceeds are shared in
     proportion to the Company's 91.5% partnership interest and Hines Interests
     Limited Partnership's and/or its affiliates' ("Hines") 8.5% partnership
     interest.

(G)  On December 31, 1997, Cornerstone purchased the second mortgage on Sixty
     State Street located in the heart of Boston's Central Business District.
     The mortgage is a cash flow mortgage through which all the economic
     benefits/risks (subject to the first mortgage) inure to the Company.
     The Company controls all major decisions regarding management and leasing.
     The total purchase price for the second mortgage was $131.5 million. The
     $78.4 million first mortgage on the property was originally recorded by the
     Company as an $89.6 million liability due to its above-market interest
     rate.

     The second mortgage, which the Company holds, is collateralized only by 
     the improvements on Sixty State Street in Boston. Title to the 
     improvements is owned by Marshall Field, who is the ground lessee under a
     ground lease that expires on December 28, 2067. The lease payments on the
     ground lease are $398,896 per annum throughout the term.

(H)  On January 28, 1998, the Company purchased Corporate 500 Centre in 
     Deerfield, Illinois. Constructed between 1986 and 1990, Corporate 500 
     Centre consists of four Class A office buildings comprising 
     approximately 680,000 rentable square feet. The total purchase price of 
     the property was approximately $150.0 million, approximately $15.0 
     million of which was paid in UPREIT Units priced at $18.50 per unit. The 
     Company financed a portion of the costs to acquire the property with an 
     $80.0 million mortgage loan from Bankers Trust Company at an interest 
     rate of LIBOR plus 1.0%. The Company had entered into an interest rate 
     swap agreement with Bankers Trust Company that effectively fixed the 
     interest rate on the mortgage loan at 6.63%; this agreement was 
     terminated in August 1998 at no cost to the Company. This swap was 
     considered a hedge for federal income tax purposes. This mortgage was 
     subsequently refinanced in October 1998 - see Footnote 5(M).

                                     8 of 30
<PAGE>

(I)  On April 28, 1998, the Company purchased One Memorial Drive in Cambridge,
     Massachusetts. The total purchase price for the property was approximately
     $112.5 million, approximately $29.0 million of which was paid in UPREIT
     Units priced at $17.50 per unit. The Company also issued 3,428,571 shares
     of Common Stock priced at $17.50 per share as part of the acquisition.

(J)  On June 3, 1998, the Company purchased 201 California Street in San
     Francisco, California, and Wilshire Palisades in Santa Monica, California.
     The total purchase price for the properties was approximately $121.5
     million, approximately $29.1 million of which was paid in UPREIT Units
     priced at $17.50 per unit. Also included in the purchase price was $64.6
     million in assumed debt.

On March 31, 1998, the Dearborn Land, an undeveloped parcel of land in Chicago
that was acquired in October 1997 along with nine Class A office properties
(collectively, the "DIHC Properties") from Stichting Pensioenfonds Voor de
Gezondheid Geestelijke en Maatschappelijke Belangen ("PGGM") and Dutch
Institutional Holding Company, Inc. ("DIHC"), was sold for net proceeds of
approximately $18,790,000, resulting in a loss of $212,228.

On April 29, 1998, the Company sold the Frick Building, located in Pittsburgh,
PA, for net proceeds of approximately $26,748,000, resulting in a loss of
$2,111,540.

3.   INVESTMENT IN REAL ESTATE JOINT VENTURE

     During October 1997, the Company acquired the first mortgage note on 
Market Square in the amount of $181.0 million which earns interest at a rate 
of 9.75%. In addition, the Company acquired a "buffer loan", with accrued 
principal and interest of $49.0 million, which accrues interest at a rate of 
11% per annum and is payable from cash flow, refinancing or sales proceeds 
from Market Square in excess of the first mortgage.

     During January 1998, the Company purchased a 99% interest in Market 
Square Development Investors ("MSDI") for approximately $5.1 million. MSDI 
owns an 85.71% interest in Market Square Associates ("MSA"), which owns a 70% 
interest in Avenue Associates Limited Partnership ("AALP"). AALP owns and 
operates Market Square. The Company's investment is accounted for under the 
equity method. The following table provides summary balance sheet information 
as of September 30, 1998 and income and expense information for the nine 
months ended September 30, 1998 for the MSA entity (amounts in thousands):
<TABLE>
<CAPTION>

                                                               1998
                                                           -------------
<S>                                                          <C>
Total Assets, primarily investments in real estate           $ 173,830
Total Liabilities, primarily notes payable to the Company      235,684
Revenues, primarily office and parking rentals                  21,403
Net Loss                                                        (6,995)

</TABLE>

     The amount recorded as earnings in real estate joint venture includes the 
interest income earned on the notes discussed above, which was offset by the 
net loss of MSA from January 30, 1998 through September 30, 1998, plus 
adjustments for straight-line rent and interest expense.

4.   OTHER DEFERRED COSTS

     Included within "other deferred costs" is $138.8 million in loans made 
by the Company between June and September 1998 to affiliates or special 
purpose entities formed by William Wilson & Associates (individually or 
collectively "Wilson"). The loans bear interest at a rate of LIBOR plus 1.50% 
and mature on December 31, 1999 ($89.1 million) and March 20, 2000 ($49.7 
million). The loans are collateralized by seven office projects and one 
parcel of undeveloped land owned by Wilson in the western United States. Upon 
consummation of the Wilson Acquisition, the outstanding loan balance will be 
offset against the purchase price. In the event that the Wilson Acquisition 
is not consummated (see Footnotes 7 and 13), Wilson is obligated to repay the 
loans and any accrued interest. The Company financed these loans in part 
through drawing on its credit facility, which bears interest at a 
weighted-average rate of approximately 6.79%.

                                     9 of 30
<PAGE>

5.   LONG-TERM DEBT

     The following table sets forth certain information regarding the 
consolidated debt obligations of the Company as of September 30, 1998, 
including mortgage obligations relating to the Company's properties. All of 
this debt, with the exception of the Convertible Promissory Note due 2001, is 
nonrecourse to the Company. However, notwithstanding the nonrecourse 
indebtedness, the lender may have the right to recover deficiencies from the 
Company in certain circumstances.

<TABLE>
<CAPTION>

                                                                           Maturity     Prepayment
Property                                 Amortization     Interest Rate    Date         Provisions        9/30/98        12/31/97
- --------                                 ------------     -------------    --------     ----------        -------        --------
                                                                                    
<S>                                    <C>               <C>              <C>         <C>                <C>            <C>
Convertible Promissory Note
 due 2001 (A)....................      Interest only     8.11% max (B)    Jan-2001    Not prepayable     $12,926,000    $12,926,000
One Norwest Center (C)............     10 year           6.90             Oct-2008     (D)                98,500,000     96,780,000
Norwest Center....................     Interest only     8.74             Dec-2005    Not prepayable     110,000,000    110,000,000
Washington Mutual Tower...........     Interest only     7.53             Nov-2005     (E)                79,100,000     79,100,000
125 Summer Street.................     Interest only (F) 7.20             Jan-2003     (G)                50,000,000     50,000,000
Tower 56..........................     30 year           7.67             May-2003     (H)                17,608,000     17,742,000
TransPotomac Plaza 5 and Charlotte
  Plaza (I).......................     Interest only     7.28             Oct-2000    Not prepayable      65,000,000     65,000,000
527 Madison Avenue and One Lincoln
  Centre (I)......................     Interest only     7.47             Oct-2004    Not prepayable      65,000,000     65,000,000
Market Square (J) and 200
  Galleria (I)....................     Interest only     7.54             Oct-2007    Not prepayable     120,000,000    120,000,000
Sixty State Street (K)............     30 year           6.84             Jan-2005     (L)                88,140,000     89,630,000
Corporate 500 Centre (M)..........     Interest only     6.63 (N)         Jul-2002    Prepayable          80,000,000       -
201 California Street (O).........     30 year           6.70             Mar-2005     (P)                33,171,000       -
Wilshire Palisades (Q)............     30 year           6.70             Jul-2002     (R)                30,109,000       -
                                                         ---------------------------                  ------------------------------
                                                         7.37%(S)         6.4 yrs. (S)                  $849,554,000   $706,178,000
</TABLE>

- ------------

(A)  The lender, Hines, has the right to convert the note into Common Stock at a
     conversion price of $14.30 per share. At maturity, the Company is entitled
     to repay the principal of the note with Common Stock priced at the lesser
     of $14.30 per share or the then-existing share price.

(B)  Lesser of 30-day LIBOR plus 0.5% or 8.11%.

(C)  On September 25, 1998, the Company completed the refinancing of the $96.1
     million mortgage on One Norwest Center with CIGNA and Mass Mutual. As a
     result of the refinancing, the principal balance was increased to $98.5
     million, the term of the loan was extended from three years to ten years
     and the interest rate was reduced from 7.50% to 6.90%.

(D)  No prepayment until October 1, 2000. From October 1, 2000 through September
     30, 2007, the prepayment fee is the greater of 1% of the outstanding
     principal balance or Treasury Yield Maintenance (as defined). Beginning
     October 1, 2007, the prepayment fee is Treasury Yield Maintenance. The loan
     may be repaid at par during the last three months of the loan.

(E)  No prepayment until September 30, 1998. Prepayable thereafter, with a
     prepayment fee equal to the greater of 1% of the outstanding principal
     balance or Treasury Yield Maintenance (as defined). Prepayment without
     fee during the six months prior to the maturity date.

(F)  Interest only payments through January 1, 2001, with a 25-year amortization
     schedule thereafter.

                                     10 of 30
<PAGE>

(G)  No prepayment until July 1, 1999. Prepayable thereafter with a 
     prepayment fee equal to the greater of 1% of the outstanding 
     principal balance or Treasury Yield Maintenance (as defined). 
     Prepayment without fee on or after three months prior to maturity date.

(H)  No prepayment until December 31, 1999. Prepayable thereafter with a 
     prepayment fee equal to the greater of 1% of the principal balance or 
     Treasury Yield Maintenance (as defined). Prepayment without fee during 
     the three months prior to the maturity date.

(I)  The three loans arising from the acquisition of several properties from
     DIHC are cross-collateralized, having the effect of forming a "collateral
     pool" for the underlying notes.

(J)  The collateral for this loan is a pledge of the $181.0 million first
     mortgage loan on Market Square which the Company purchased from PGGM.

(K)  While the face amount of the loan is $77,938,000, and the interest rate is
     9.5%, the Company is carrying the debt at $88,140,000, which is the market
     value of the loan at the time of the closing, less the amortization of
     principal and premium since closing, based upon a market interest rate for
     similar quality loans of 6.84%.

(L)  No prepayment until February 1, 2000. Prepayable thereafter with a 
     prepayment fee equal to the greater of 2% of the outstanding principal 
     balance or Treasury Yield Maintenance (as defined). The 2% maximum is 
     reduced by 0.25% per annum thereafter until it reaches 1%. Prepayment 
     without fee during the 90 days prior to the maturity date.

(M)  On October 9, 1998, the Company completed the refinancing of the $80.0
     million mortgage on Corporate 500 Centre with Teachers Insurance and
     Annuity Association. As a result of the refinancing, the principal balance
     was increased to $90.0 million, the term of the loan was extended from 4.5
     years to 10 years and the interest rate was increased by three basis points
     to 6.66%.

(N)  The interest rate on the loan is LIBOR plus 100 basis points.

(O)  While the face amount of the loan is $32,842,000, and the interest rate is
     6.9%, the Company has recorded the debt at $33,171,000, which is the market
     value of the loan at the time of the closing, less the amortization of
     principal and premium since closing, based upon a market interest rate for
     similar quality loans of 6.70%.

(P)  No prepayment until March 15, 2001. Prepayable thereafter with a
     prepayment fee, if paid in full, equal to the greater of 1% of the
     amount being prepaid or Modified Yield Maintenance (as defined). If a
     partial prepayment is made, the prepayment fee is equal to Modified Yield
     Maintenance. Prepayment without fee during the 120 days prior to the
     maturity date.

(Q)  While the face amount of the loan is $28,841,000, and the interest rate is
     8.04%, the Company has recorded the debt at $30,109,000, which is the
     market value of the loan at the time of the closing, less the amortization
     of principal and premium since closing, based upon a market interest rate
     for similar quality loans of 6.70%.

(R)  No prepayment until July 1, 1998. Prepayable thereafter with 60 days notice
     to Lender, with a prepayment fee equal to the greater of 1% of the
     outstanding principal balance or Yield Maintenance (as defined).

(S)  Weighted-average interest rate and term of the Company's long-term
     debt.

Since most of the long-term debt is collateralized by property, there are
restrictive covenants that limit the total amount of indebtedness that can be
placed on individual properties.

                                    11 of 30
<PAGE>

6.   CREDIT FACILITY

     The Company has a $350 million Revolving Credit Facility with Bankers 
Trust Company and The Chase Manhattan Bank for acquisitions and general 
working capital purposes as well as the issuance of letters of credit. The 
interest rate on the line of credit depends on the Company's leverage ratio 
at the time of borrowing and will be at a spread of 1.10% to 1.40% over LIBOR 
or the Prime Rate at the borrower's option. The letters of credit will be 
priced at the applicable Eurodollar credit spread. The line of credit expires 
on October 27, 2000. As of September 30, 1998, $148.0 million of the credit 
line was outstanding at a weighted-average interest rate of approximately 
6.79% as well as a $0.9 million letter of credit at a spread of 1.40%. The 
letter of credit  expired on November 2, 1998. The line of credit contains 
certain restrictive covenants including; (i) a limitation on the Company's 
dividend to 90% of funds from operations and 110% of cash available for 
distribution; (ii) the percentage of total liabilities to total property 
asset value (as defined) cannot exceed 55%; (iii) the ratio of adjusted 
EBITDA to interest expense may not be less than 2.25 to 1.00; (iv) the fixed 
charge coverage ratio may not be less than 1.75 to 1.00; and (v) the ratio of 
total property asset value to secured indebtedness may not be less than 2.50 
to 1.00.

7.   COMMITMENTS AND CONTIGENCIES

     The Company has entered into an agreement to purchase a 912,000 square foot
Class A office building, currently under development, in downtown Minneapolis,
Minnesota, for an estimated cost of approximately $160.0 million, of which
approximately $33.0 million has been spent to date. The project is scheduled to
be completed in the year 2000 and is approximately 50% pre-leased. The
development is to be financed through a construction loan by U.S. Bank. Upon
completion, the Company will retire the construction loan and acquire the
property from the developer for an amount to be determined by applying a
negotiated formula to in-place net operating income.

     On June 22, 1998, the Company entered into an agreement to merge with 
and acquire certain assets from Wilson, a private real estate developer, 
property manager and owner based in San Mateo, California. The Company will 
acquire the Wilson operating company and approximately 9.1 million square 
feet of Wilson's Class A office buildings in the San Francisco Bay Area, 
Southern California, Phoenix, Salt Lake City and Seattle (the "Wilson 
Acquisition"). The total purchase price for the Wilson Acquisition is 
estimated to be approximately $1.81 billion and is expected to close during 
the fourth quarter of 1998. See Footnote 13.

8.   STOCKHOLDERS' INVESTMENT

     The 7% Cumulative Convertible Preferred Stock is convertible into Common
Stock at $16.50 per share at any time after August 4, 2000.

     On April 21, 1997, Cornerstone completed its initial public offering
("IPO") in the United States of 16.1 million shares of Common Stock at a price
of $14 per share. The Company received net proceeds of approximately $207.8
million ($225.4 million gross proceeds less an underwriting discount of
approximately $14.1 million and expenses of approximately $3.5 million).

     On February 6, 1998, Cornerstone completed a secondary public offering 
of 14,375,000 shares of Common Stock at $18.25 per share. The shares were 
placed in the U.S. through a syndicate of seven investment banks led by 
Merrill Lynch & Co. Net proceeds to the Company were approximately $247.9 
million (approximately $262.3 million gross proceeds less an underwriting 
discount of approximately $13.7 million and expenses of approximately $0.7
million). The net proceeds were used to repay outstanding borrowings under 
the Revolving Credit Facility and for working capital purposes.


                                    12 of 30
<PAGE>

     The following tables summarize the stock options and restricted stock
grants for certain officers of the Company as of September 30, 1998:

<TABLE>
<CAPTION>

Stock Options

                    Options Granted   Exercise Price                               Options         Options
  Date of Grant     (No. of shares)   (per share)           Vesting(A)           Exercisable      Exercised
  -------------     ---------------   -----------           ----------           -----------      ---------
<S>                 <C>               <C>               <C>                      <C>              <C>
August, 1995 ....        637,500       $   14.30        33.3%/yr, 10yr term        637,500                 0
October, 1995 ...        150,000       $   14.30        33.3%/yr, 10yr term        100,000            10,500
March, 1997 .....        880,000       $   14.50        33.3%/yr, 10yr term        293,333                 0
November, 1997 ..         70,000       $   18.44        33.3%/yr, 10yr term              0                 0
February, 1998 ..         70,000       $   18.13        33.3%/yr, 10yr term              0                 0
February, 1998 ..        595,000       $   18.25        33.3%/yr, 10yr term              0                 0
March, 1998 .....        200,000       $   18.25        33.3%/yr, 10yr term              0                 0
                                                                                              
</TABLE>



Restricted Stock Grants

<TABLE>
<CAPTION>

                           Shares Granted           Value at Grant  
      Date of Grant        (No. of shares)          Date (per share)                        Vesting (B)
      -------------        ---------------          ----------------                        -----------
<S>                        <C>                      <C>                   <C>
August, 1995                     167,622                 $14.30           The grant will fully vest with respect to 13.333% on June
                                                                          30, 1996, 1997, 1998, 1999 and with respect to 46.668% on
                                                                          June 30, 2000.
March, 1997                      100,000                 $16.38           The grant will fully vest with respect to 13.333% on June
                                                                          30, 1998, 1999, 2000, 2001 and with respect to 46.668% on
                                                                          June 30, 2002.
November, 1997                    12,500                 $18.44           The grant will fully vest with respect to 13.333% on June
                                                                          30, 1998, 1999, 2000, 2001 and with respect to 46.668% on
                                                                          June 30, 2002.
March, 1998                       12,500                 $18.13           The grant will fully vest with respect to 13.333% on
                                                                          March 15, 1999, 2000, 2001, 2002 and with respect to
                                                                          46.668% on March 15, 2003.
March, 1998                       19,178                 $18.25           The grant will fully vest with respect to 13.333% on
                                                                          March 15, 1999, 2000, 2001, 2002 and with respect to
                                                                          46.668% on March 15, 2003.
</TABLE>
- --------

(A)  The vesting schedule for the options were amended from 20%/yr, 10yr term to
     33.3%/yr, 10yr term on February 4, 1998.

(B)  Deferred compensation of approximately $4,842,000 is being amortized
     according to the respective amortization schedule for each vesting period
     noted above, with the unamortized balance of approximately $1,978,000 shown
     as a deduction from stockholders' investment. Regular dividends are paid
     on restricted stock.

9.   STOCKHOLDERS' AND UNITHOLDERS' DISTRIBUTIONS

     A cash dividend and Unitholder distribution of $0.30 per share/unit was 
declared for the first quarter of 1998 and paid on February 27, 1998, to 
Common Stockholders and Unitholders of record as of January 30, 1998. A cash 
dividend and Unitholder distribution of $0.30 per share/unit was declared for 
the second quarter of 1998 and paid on May 29, 1998, to Common Stockholders 
and Unitholders of record as of April 30, 1998. A cash dividend and 
Unitholder distribution of $0.30 per share/unit was declared for the third 
quarter of 1998 and paid on August 31, 1998, to Common Stockholders and 
Unitholders of record as of July 31, 1998.

                                    13 of 30
<PAGE>

10.  INCOME PER COMMON SHARE

     The tables below set forth the calculation of income per common share for
the three and nine months ended September 30, 1998 and 1997 (dollar amounts in
thousands, except per share amounts):

<TABLE>
<CAPTION>
                                                                            Three Months Ended
                                                          -------------------------------------------------------
                                                              September 30, 1998            September 30, 1997
                                                          ----------------------------    -----------------------
                                                              Basic        Diluted          Basic      Diluted
                                                          -------------- -------------    ----------- -----------
<S>                                                         <C>             <C>             <C>       <C>      
               Proceeds upon exercise of options            $    --         $  40,940       $    --   $  24,021
               Market price of shares
                    average for the respective period       $    --         $   15.91       $    --   $   17.31
               Treasury shares that could be 
                    repurchased (options)                        --             2,573            --       1,388
               Option shares outstanding                         --             2,592            --       1,668
               Weighted common stock equivalent
                    shares (Excess shares under option
                    over Treasury shares that could
                    be repurchased)                              --               157            --         280
               Weighted average common shares
                    outstanding                               101,574         101,574          45,804    45,804
                                                            ---------       ---------       --------- ---------
               Adjusted weighted average common
                    shares outstanding                        101,574         101,731          45,804    46,084


               Net income for the period                    $  18,958       $  18,958       $   8,076 $   8,076
               Income applicable to
                    preferred stock                         $   (875)       $   (875)       $   (875) $   (875)
                                                            ---------       ---------       --------- ---------
               Income available to 
                    common shares                           $  18,083       $  18,083       $   7,201 $   7,201
               Income per common share                      $    0.18       $    0.18       $    0.16 $    0.16

</TABLE>

<TABLE>
<CAPTION>
                                                                            Nine Months Ended
                                                          -------------------------------------------------------
                                                              September 30, 1998            September 30, 1997
                                                          ----------------------------    -----------------------
                                                              Basic        Diluted          Basic      Diluted
                                                          -------------- -------------    ----------- -----------
<S>                                                       <C>            <C>              <C>         <C>     
               Proceeds upon exercise of options          $   --         $ 40,940         $   --      $ 24,021
               Market price of shares                                                   
                   average for the respective period      $   --         $  17.29         $   --      $  16.14
               Treasury shares that could be                                            
                   repurchased (options)                      --            2,368             --         1,488
               Option shares outstanding                      --            2,592             --         1,668
               Weighted common stock equivalent                                         
                   shares (Excess shares under option                                   
                   over Treasury shares that could be                                   
                   repurchased)                               --              276             --           179
               Weighted average common shares                                           
                   outstanding                              98,312         98,312           33,494      33,494
                                                          --------       --------         --------    --------
               Adjusted weighted average common                                         
                   shares outstanding                       98,312         98,588           33,494      33,673
                                                                                        
               Net income for the period                  $ 60,964       $ 60,964         $ 21,666    $ 21,666
               Income applicable to                                                     
                   preferred stock                        $ (2,625)      $ (2,625)        $ (9,285)   $ (9,285)
                                                          --------       --------         --------    --------
               Income available to                                                      
                   common shares                          $ 58,339       $ 58,339         $ 12,381    $ 12,381
               Income per common share                    $   0.59       $   0.59         $   0.37    $   0.37
                                                                                        
</TABLE>

                                    14 of 30
<PAGE>

11.  SUPPLEMENTAL CASH FLOW INFORMATION

     Cash paid for interest was approximately $46,981,000 and $21,955,000 for
the nine months ended September 30, 1998 and 1997, respectively.

Non-Cash Investing and Financing Activities

     On January 5, 1998, the Company purchased the participation rights in the
cash flow and residual value of Tower 56 from the former participants for
307,692 shares of Common Stock.

     On January 28, 1998, the Company purchased Corporate 500 Centre, a complex
of four office buildings in Deerfield, Illinois. As part of the total purchase
price of approximately $150.0 million, the Company issued 822,794 UPREIT Units
priced at $18.50 per unit.

     On April 28, 1998, the Company purchased One Memorial Drive, an office
tower in Cambridge, Massachusetts. As part of the total purchase price of
approximately $112.5 million, the Company issued 3,428,571 shares of Common
Stock and 1,657,426 UPREIT Units, both priced at $17.50.

     On June 3, 1998, the Company purchased 201 California Street in San
Francisco, California, and Wilshire Palisades in Santa Monica, California. As
part of the total purchase price for the Properties of approximately $121.5
million, the Company assumed $64.6 million in debt and issued 1,665,663 UPREIT
Units priced at $17.50 per unit.

     On September 25, 1998, in conjunction with the refinancing of the One
Norwest Center mortgage, the Company incurred an extraordinary loss of $507,022,
which represented the unamortized deferred financing costs on the previous One
Norwest Center mortgage at the time of the refinancing.

12.  PRO FORMA FINANCIAL INFORMATION

     The pro forma financial information shown below is based on the 
consolidated historical statements of Cornerstone after giving effect to the 
acquisitions of 527 Madison Avenue, the DIHC Properties, Corporate 500 
Centre, One Memorial Drive, 201 California Street and Wilshire Palisades as 
if such acquisitions took place on January 1, 1998 and 1997, respectively. 
The pro forma financial information is presented for informational purposes 
only and may not be indicative of results that would have actually occurred 
had the acquisitions taken place at the date indicated. Also, they may not be 
indicative of the results that may be achieved in the future.

<TABLE>
<CAPTION>

            September 30,                              1998                 1997
            -------------                              ----                 ----
<S>                                               <C>                  <C>          
Pro forma total revenues                          $ 269,769,000        $ 246,576,000
Pro forma income before extraordinary items          63,165,000           68,080,000
Pro forma net income                                 60,896,000           68,026,000
Pro forma extraordinary loss per share                    (0.02)                0.00
Pro forma income per share                                 0.58                 0.83
</TABLE>

                                    15 of 30
<PAGE>

13.  OTHER MATTERS

     On June 22, 1998, the Company entered into an agreement to merge with 
and acquire certain assets from Wilson, a private real estate developer, 
property manager and owner based in San Mateo, California. The Company will 
acquire the Wilson operating company and approximately 9.1 million square 
feet of Wilson's Class A office buildings in the San Francisco Bay Area, 
Southern California, Phoenix, Salt Lake City and Seattle. The total purchase 
price for Wilson and its portfolio is expected to be approximately $1.81 
billion. At this price, it is anticipated that the Company will issue to 
Wilson and its investors approximately $635 million in Common Stock and 
UPREIT Units, at a stated price of $17.25 per share/unit, and pay cash for 
the remaining equity. In addition, the Company will assume or repay 
approximately $780 million of existing indebtedness currently held by Wilson. 
The cash needed for the transaction will be financed under the Revolving 
Credit Facility and from an expected sale of $200 million of Common Stock to 
PGGM, a 31% equity holder in the Company at September 30, 1998, at an agreed 
price of $17.25 per share. The consummation of the Wilson Acquisition is 
subject to the approval of the stockholders of the Company and the investors 
of Wilson, as well as other outstanding closing conditions. The Wilson 
investors consented to the transaction in September 1998. The Company's proxy 
statement has been filed and distributed to its stockholders. Upon approval 
of the transaction by the Company's stockholders, the transaction will close 
in the fourth quarter of 1998.

14.  SUBSEQUENT EVENTS

     A cash dividend and Unitholder distribution of $0.30 per share/unit was 
declared for the fourth quarter of 1998 to Common Stockholders and 
Unitholders of record as of October 30, 1998, to be paid on November 30, 1998.

     On November 4, 1998, a syndicate of banks led by BT Alex. Brown, Chase 
Securities, and NationsBank Montgomery Securities provided the Company with a 
$550 million line of credit for acquisitions and general working capital 
purposes. The interest rate on the line of credit depends on the Company's 
leverage ratio at the time of borrowing and will be at a spread of 1.10% to 
1.40% over LIBOR. These are the same terms as the Company's previous $350 
million line of credit, which was retired at the closing of the new line of 
credit. The $550 million line of credit expires on November 4, 2001. On 
November 4, 1998, the amount outstanding on the previous line of credit was 
transferred to the banks taking part in the syndicate providing the new line 
of credit.

     On November 6, 1998, the Company purchased an additional 14.29% partnership
interest in MSA for $4.0 million. Upon completion of the transaction, the
Company effectively owns 99.14% of the MSA entity, which has a 70% interest in
AALP. AALP owns and operates Market Square (see Footnote 3). The Company will 
consolidate Market Square in the fourth quarter.

                                    16 of 30
<PAGE>

Item 2

     MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS
      OF OPERATIONS FOR THE THREE AND NINE MONTHS ENDED SEPTEMBER 30, 1998


RESULTS OF OPERATIONS

Consolidation

     Cornerstone's principal source of income is rental revenues received 
through its investment in fourteen fee simple properties, six real estate 
partnerships and one mortgage. NWC, Third Partnership, 191 Peachtree, 222 
Berkeley and 500 Boylston have been consolidated because Cornerstone has a 
majority interest in the economic benefits and is or has the right to become 
managing general partner at its sole discretion. The Company has accounted 
for its investment in MSA using the equity method because it does not have 
sufficient control of the day to day operations of the partnership.

Property Results

     For the three and nine months ended September 30, 1998 and 1997, 
Property results can be summarized as follows (amounts in thousands):

<TABLE>
<CAPTION>

                                           For the three           For the three         For the nine        For the nine
                                            months ended            months ended         months ended        months ended
                                          September 30, 1998     September 30, 1997   September 30, 1998  September 30, 1997
                                         --------------------    ------------------   ------------------  ------------------

<S>                                             <C>                    <C>                  <C>                 <C>     
Office and Parking Rentals                      $83,227                $34,546              $239,767            $103,237
Less:
  Building Operating Expenses                    18,896                  7,660                52,947              22,693
  Real Estate Taxes                              12,034                  5,933                34,900              17,553
  Depreciation and Amortization                  15,702                  7,057                42,561              20,865
                                                -------                -------              --------             -------
Total Operating Expenses                         46,632                 20,650               130,408              61,111
                                                -------                -------              --------             -------
Total Property Income                           $36,595                $13,896              $109,359             $42,126
                                                -------                -------              --------             -------
                                                -------                -------              --------             -------

</TABLE>

     The increase in property income of $22.7 million for the three months 
ended September 30, 1998 as compared to the same period in 1997 was due to 
additional revenue of $22.6 million derived from 13 properties acquired since 
September 30, 1997. At the properties held during both periods (the "Existing 
Propoerties"), property income at One Norwest Center increased $0.4 million 
due to increased rental rates. The remaining increase of $0.1 million was 
caused by slight variances in property income at the existing properties. 
These increases were offset by a reduction in property income of $0.4 million 
at the Frick Building which was due to the sale of this building in April 
1998. 

     The increase in property income of $67.2 million for the nine months 
ended September 30, 1998 as compared to the same period in 1997 was due to 
the additional revenue of $65.9 million derived from 13 properties acquired 
since September 30, 1997 and an increase of $0.7 million in revenues from 527 
Madison Avenue because it was purchased in February 1997. At the Existing 
Properties, property income at One Norwest Center increased $0.2 million due 
to increased rental rates. Washington Mutual Tower increased $0.6 million due 
to increased rental rates and parking revenue. 125 Summer Street increased 
$0.6 million due to increased rental rates and the lease up of the former 
Gadsby and Hannah space which was vacant during the same period in 1997. 
These increases were offset by a reduction in property income of $0.6 million 
at the Frick Building which was due to the sale of this building in April 
1998. The remaining decrease of $0.2 million was caused by slight variances 
in property income at the other properties.

                                    17 of 30

<PAGE>

Earnings in Real Estate Joint Venture

    The earnings in real estate joint venture of approximately $10.1 million 
for the nine months ended September 30, 1998 was due to the acquisition of 
the mortgage loan and "buffer loan" on Market Square in October 1997 and the 
partnership interest in Market Square in January 1998. The amount is 
comprised of approximately $15.1 million of interest earned on the loans 
which is offset by an equity in loss pickup of approximately $5.0 million.

Interest and Other Income

     Interest and other income decreased to approximately $2.0 million for 
the three months ended September 30, 1998 from approximately $3.9 million for 
the three months ended September 30, 1997. These amounts primarily consist of 
interest earned from short-term investments, management fee income, lease 
cancellation payments and income from advisory contracts in 1997. The 
decrease was due to a reduction in interest income of $2.7 million on 
short-term investments due to the Company having excess cash in 1997 from its 
preferred stock placement that occurred in late 1996 as well as its IPO in 
April 1997, a reduction of $0.6 million due to the expiration of certain 
advisory contracts in 1997 and a reduction in lease cancellation income of 
$0.3 million. These amounts were offset by an increase of $0.8 million in 
tenant alteration income, a $0.4 million increase in management fee income 
and an increase of $0.5 million in other income.

     Interest and other income decreased to approximately $7.2 million for 
the nine months ended September 30, 1998 from approximately $8.4 for the nine 
months ended September 30, 1997. These amounts primarily consist of interest 
earned from a mortgage note receivable, short-term investments, a note 
receivable from a partner, management fee income and income from advisory 
contracts in 1997. The decrease was due to a reduction in interest income of 
$4.7 million on short-term investments due to the Company having excess cash 
in 1997 from its preferred stock placement that occurred in late 1996 as well 
as its IPO in April 1997, a reduction of $0.9 million due to the expiration 
of certain advisory contracts in 1997 and a reduction of $0.1 million in 
interest received from the note receivable from a partner due to the 
reduction in principal. These amounts were offset by an increase of $2.0 
million in tenant alteration income, an increase of $1.8 million due to the 
purchase of the mortgage note on Market Square in late 1997 and an increase 
of $0.7 million in management fee income.

Interest Expense

     Interest expense incurred by Cornerstone relating to its financing 
activities increased to approximately $16.1 million for the three months 
ended September 30, 1998 from approximately $7.4 million for the three months 
ended September 30, 1997. The increase in interest expense was due to $4.7 
million of interest expense on the purchase money loans from the DIHC 
transaction, an increase in interest expense of $0.2 million on the Revolving 
Credit Facility, an increase of $0.2 million in amortization of deferred 
financing costs, interest of $1.5 million on the Sixty State Street loan, 
interest of $1.3 million on the Corporate 500 Centre loan, interest of $0.5 
million on the 201 California Street loan and interest of $0.5 million on the 
Wilshire Palisades loan. These increases were offset by the decrease of $0.2 
million due to the refinancing of the One Norwest Center loan, as discussed 
below.

     Interest expense incurred by Cornerstone relating to its financing 
activities increased to approximately $47.7 million for the nine months ended 
September 30, 1998 from approximately $22.4 million for the nine months ended 
September 30, 1997. The increase in interest expense was due to $13.7 million 
of interest expense on the purchase money loans from the DIHC transaction, an 
increase in interest expense of $2.0 million on the Revolving Credit 
Facility, an increase of $0.6 million in amortization of deferred financing 
costs, interest of $4.6 million on the Sixty State Street loan, interest of 
$3.6 million on the Corporate 500 Centre loan, interest of $0.7 million on 
the 201 California Street loan and interest of $0.7 million on the Wilshire 
Palisades loan. These increases were offset by a decrease of $0.4 million due 
to the Term Loan interest and a decrease of $0.2 million due to the 
refinancing of the One Norwest Center loan, both as discussed below.

                                    18 of 30

<PAGE>

General and Administrative Expenses

     The aggregate amount of Cornerstone's general and administrative 
expenses have increased to approximately $3.2 million for the three months 
ended September 30, 1998 from approximately $1.9 million for the three months 
ended September 30, 1997. The increase in 1998 from 1997 of $1.3 million is 
due to the additional employees, space, systems and other support necessary 
to manage the substantial growth in assets of the Company during the most 
recent twelve-month period. Included in the increase is approximately $1.1 
million of accrued bonus expense which is expected to be paid upon 
consummation of the Wilson Acquisition.

     The aggregate amount of Cornerstone's general and administrative 
expenses have increased to approximately $8.7 million for the nine months 
ended September 30, 1998 from approximately $5.1 million for the nine months 
ended September 30, 1997. The increase in 1998 from 1997 of $3.6 million is 
due to the additional employees, space, systems and other support necessary 
to manage the substantial growth in assets of the Company during the most 
recent twelve-month period. Included in the increase is approximately $1.1 
million of accrued bonus expense which is expected to be paid upon 
consummation of the Wilson Acquisition.

Loss on Sale of Real Estate Assets

     On March 31, 1998, the Dearborn Land, an undeveloped parcel of land in 
Chicago that was acquired in October 1997 along with nine Class A office 
properties from PGGM and DIHC was sold for net proceeds of approximately 
$18.8 million, resulting in a loss of approximately $0.2 million.

     On April 29, 1998, the Company sold the Frick Building, located in 
Pittsburgh, PA, for net proceeds of approximately $26.7 million, resulting in 
a loss of approximately $2.1 million.

Minority Interest

     Minority interest increased to approximately $1.8 million for the three 
months ended September 30, 1998 from approximately $0.4 million for the three 
months ended September 30, 1997 due to the allocation of income to the 
Unitholders and the purchase of the partnership interests in 500 Boylston, 
222 Berkeley and 191 Peachtree.

     Minority interest increased to approximately $4.7 million for the nine 
months ended September 30, 1998 from approximately $1.4 million for the nine 
months ended September 30, 1997 due to the allocation of income to the 
Unitholders and the purchase of the partnership interests in 500 Boylston, 
222 Berkeley and 191 Peachtree.

Interest Rate Swaps

     During 1998, the Company had entered into a $80.0 million interest rate 
swap to protect it from interest rate fluctuations that could have affected 
its floating rate debt on Corporate 500 Centre. The swap effectively fixed 
the interest rate on the $80.0 million loan at 6.63%. This agreement was 
terminated in August 1998 at no cost to the Company. The swap was considered 
a hedge for federal income tax purposes.

                                    19 of 30

<PAGE>

LIQUIDITY AND CAPITAL RESOURCES

Cash Flow (dollar amounts in thousands)

<TABLE>
<CAPTION>

                                           For the nine months ended       For the nine months ended
Cash flow provided by (used in):               September 30, 1998              September 30, 1997
- --------------------------------           -------------------------       ------------------------- 
<S>                                               <C>                              <C>       
Operating activities                              $   116,786                      $   43,472
Investing activities                                 (303,632)                        (74,161)
Financing activities                                  192,682                         140,760
Earnings to fixed charges ratio                          2.16                            1.39

</TABLE>

     Cash provided by operating activities increased to approximately $116.8 
million for the nine months ended September 30, 1998 from approximately $43.5 
million for the nine months ended September 30, 1997. The increase is 
primarily due to the cash flows from the interests in 13 properties acquired 
since the end of the third quarter of 1997.

     Cash used in investing activities increased to approximately $303.6 
million for the nine months ended September 30, 1998 from approximately $74.2 
million for the nine months ended September 30, 1997 due to the acquisition 
of Corporate 500 Centre for approximately $135.0 million (net of UPREIT 
Units), One Memorial Drive for approximately $23.5 million (net of Common 
Stock and UPREIT Units) and 201 California Street and Wilshire Palisades for 
approximately $28.1 million (net of assumed debt and UPREIT Units). Further 
adding to the increase was the net change in the investment in Market Square 
of approximately $7.1 million, an increase in deferred costs of approximately 
$141.0 million and other property additions of approximately $15.5 million. 
These investments were partially offset by the approximately $18.8 million 
and approximately $26.7 million in proceeds from the sale of the Dearborn 
Land and the Frick Building, respectively. In addition, these investments 
were partially offset by the receipt of approximately $1.1 million from the 
repayment of notes receivable. During 1997, the Company invested 
approximately $67.0 million in 527 Madison Avenue and approximately $8.1 
million in other property investments. These investments were slightly offset 
by the receipt of approximately $0.9 million from the repayment of notes 
receivable.

     Cash provided by financing activities increased to approximately $192.7 
million for the nine months ended September 30, 1998 from approximately 
$140.8 million for the nine months ended September 30, 1997. The increase was 
mainly due to the secondary offering proceeds of approximately $262.3 million 
compared to approximately $225.4 million received from the Company's IPO in 
1997, an increase in mortgage borrowings of approximately $47.4 million, a 
decrease in restricted cash of approximately $32.0 million and a decrease in 
stock and debt issuance costs of approximately $2.5 million. Further adding 
to the increase was a decrease in loan repayments of approximately $30.8 
million and a decrease in preferred distributions of approximately $6.7 
million. These amounts were offset by an increase in credit facility 
repayments versus credit facility borrowings of approximately $39.0 million, 
a decrease in proceeds from the dividend reinvestment plan of approximately 
$3.4 million, an increase in distributions to minority partners of 
approximately $4.3 million, an increase in net swap termination and debt 
prepayment costs of approximately $1.6 million and an increase in dividends 
paid of approximately $56.1 million.

     The ratio of earnings to fixed charges and dividends on preferred stock 
increased to 2.16 times at September 30, 1998 from 1.39 times at September 
30, 1997 due to the substantial reduction of the Company's leverage ratio and 
the conversion of the 8% preferred shares into Common Stock.

Funds From Operations

     The Company calculates Funds from Operations ("FFO") based upon guidance 
from the National Association of Real Estate Investment Trusts ("NAREIT"). 
FFO is defined as net income, excluding gains or losses from debt 
restructuring and sales of property, plus depreciation and amortization, 
after adjustments for unconsolidated joint ventures. The Company has adjusted 
1997 FFO by the net gain on interest rate swap due to the non-cash nature of 
this item.

     Industry analysts generally consider FFO to be an appropriate measure of 
performance of a REIT such as Cornerstone. FFO does not represent cash 
generated from operating activities in accordance with generally accepted 
accounting principles and, therefore, should not be considered a substitute 
for net income as a measure of performance or a substitute for cash flow from 
operations as a measure of liquidity calculated in accordance with generally 
accepted accounting principles.

                                    20 of 30

<PAGE>

The Company believes that FFO is helpful to investors as a measure of the
performance of an equity REIT because, along with cash flows from operating
activities, financing activities and investing activities, it provides investors
an understanding of the ability of the Company to generate earnings from its 
recurring operations, after the payment of all administrative costs and 
interest expense. For cash flows from operating, financing and
investing activities, see the Condensed Consolidated Statements of Cash Flows
included in the Condensed Consolidated Financial Statements which are part of
this report.

     The Company no longer reports free and deferred rental income as an 
adjustment to FFO because this is not part of the industry standard. 
Therefore, included in FFO for the three months ended September 30, 1998 is 
an increase of approximately $3,483,000 and a decrease of approximately 
$38,000 for the three months ended September 30, 1997, for free and deferred 
rental income (after adjustment for minority interest). Included in FFO for 
the nine months ended September 30, 1998 and 1997 is an increase of 
approximately $10,392,000 and $746,000, respectively, for free and deferred 
rental income (after adjustment for minority interest).

     The table below sets forth the adjustments which were made to the net 
income of the Company in the calculation of FFO for the three and nine month 
periods ended September 30, 1998 and 1997, respectively (amounts in 
thousands):

                            Funds From Operations (1)
<TABLE>
<CAPTION>

                                           Three Months            Three Months           Nine Months           Nine Months
                                              Ended                   Ended                  Ended                 Ended
                                        September 30, 1998      September 30, 1997     September 30, 1998    September 30, 1997
                                        ------------------      ------------------     ------------------    ------------------
<S>                                            <C>                    <C>                    <C>                   <C>     
Net income                                     $ 18,958               $  8,076               $ 60,964              $ 21,666

NAREIT adjustments:
   Depreciation and amortization (2)             15,702                  7,057                 42,561                20,865
   Realized/unrealized gain on swaps                  0                      0                      0                   (99)
   Minority adjustments                            (407)                  (307)                (1,415)               (1,044)
   Unconsolidated depreciation                    1,380                      0                  3,554                     0
   Loss on sale of real estate assets               127                      0                  2,324                     0
   Extraordinary losses/swap losses               2,269                      0                  2,269                    54

Other adjustments:
   Amortization on rent notes                       387                    346                  1,133                   903
   Minority interest allocated to             
    unitholders                                     780                      0                  1,426                     0  
                                               --------               --------               --------              --------

Funds from operations                            39,196                 15,172                112,816                42,345

Interest expense on convertible note                200                    199                    604                   592
                                               --------               --------               --------              --------

Funds from operations available for            
   diluted shares                              $ 39,396               $ 15,371              $ 113,420              $ 42,937
                                               --------               --------               --------              --------
                                               --------               --------               --------              --------
</TABLE>

- -----------------

(1) Although the Company believes that this table is a full and fair
    presentation of the Company's FFO, similarly captioned items may be defined
    differently by other REITs, in which case direct comparisons may not be
    possible.

(2) The depreciation and amortization adjustment does not include amortization
    of deferred financing costs and depreciation of non-real estate assets in
    accordance with guidance from NAREIT.


                                    21 of 30

<PAGE>

     The increase in FFO for the three and nine month periods ended September 
30, 1998 as compared to the same periods in 1997 is primarily due to the 
acquisition of interests in 14 properties since the end of the February of 
1997.

     The Company will seek to continue increasing FFO and the value of its 
property portfolio by acquiring additional properties that the Company 
believes will produce favorable returns. As part of its ongoing business, the 
Company periodically engages in discussions with public and private real 
estate entities regarding possible portfolio or asset acquisitions or 
business combinations.

Capital Stock Transactions

     On January 31, 1997, through a dividend reinvestment plan available to 
its German stockholders, Cornerstone received proceeds of approximately $3.7 
million and issued an additional 243,907 shares of Common Stock to such 
stockholders.

     On April 21, 1997, the Company received approximately $225.4 million 
gross proceeds from the public placement of 16,100,000 new shares of Common 
Stock at a price of $14.00 per share and listed on the New York Stock 
Exchange through underwriters led by Merrill Lynch & Co. The net proceeds 
were used as partial consideration for the purchase of the DIHC Properties.

     On April 30, 1997, through a dividend reinvestment plan available to its 
German stockholders, Cornerstone received proceeds of approximately $2.2 
million and issued an additional 141,733 shares of Common Stock to such 
stockholders.

     On July 25, 1997, the 1,148,276 shares of Redeemable Preferred stock 
outstanding at the time were converted into 11,482,760 shares of Common 
Stock. The contractual conversion was based upon meeting a $16.00 twenty-day 
average price per share of Common Stock.

     On July 31, 1997, through a dividend reinvestment plan available to its 
German stockholders, Cornerstone received proceeds of approximately $2.6 
million and issued an additional 175,796 shares of Common Stock to such 
stockholders.

     On October 27, 1997, the Company increased the authorized shares from 
115,000,000 shares of capital stock, without par value, to 265,000,000 shares 
of capital stock, without par value, of which 15,000,000 shares were 
preferred stock and 250,000,000 shares were Common Stock.

     On October 28, 1997, as consideration for the acquisition of the DIHC 
Properties, Cornerstone issued 34,185,500 shares of Common Stock to DIHC and 
PGGM as compensation for the acquisition of interests in nine Class A office 
buildings and an undeveloped parcel of land.

     On October 31, 1997, through a dividend reinvestment plan available to 
its German stockholders, Cornerstone received proceeds of approximately $2.5 
million and issued an additional 134,577 shares of Common Stock to such 
stockholders.

     On January 5, 1998, the Company purchased the participation rights in 
the cash flow and residual value of Tower 56 from the former participants for 
307,692 shares of Common Stock.

     On February 6, 1998, Cornerstone completed a secondary public offering of
14,375,000 shares of Common Stock at $18.25 per share. The shares were placed
in the U.S. through a syndicate of seven investment banks led by Merrill
Lynch & Co. Net proceeds to the Company were approximately $247.9 million
(approximately $262.3 million gross proceeds less an underwriting discount of 
approximately $13.7 million and expenses of approximately $0.7 million). 
The net proceeds were used to repay the Company's acquisition line of credit
and for working capital purposes.

                                    22 of 30

<PAGE>

     On February 27, 1998, through a dividend reinvestment plan available to 
its German stockholders, Cornerstone received proceeds of approximately $2.0 
million and issued an additional 109,007 shares of Common Stock to such 
stockholders.

     On April 28, 1998, the Company issued 3,428,571 shares of Common Stock 
to Prudential Securities as partial consideration for the acquisition of One 
Memorial Drive.

     On May 20, 1998, the Company increased the number of authorized 
Preferred Stock from 15,000,000 shares to 65,000,000 shares.

     On May 29, 1998, through a dividend reinvestment plan available to its 
German stockholders, Cornerstone received proceeds of approximately $1.8 
million and issued an additional 98,487 shares of Common Stock to such 
stockholders.

     On August 31, 1998, through a dividend reinvestment plan available to 
its German stockholders, Cornerstone received proceeds of approximately $1.5 
million and issued an additional 94,610 shares of Common Stock to such 
stockholders.

Mortgage Indebtedness

     On October 27, 1997, the Company entered into three mortgage loans with 
PGGM and its wholly-owned subsidiary DIHC as purchase money financing for the 
DIHC Properties. The mortgages, which are cross-collateralized, encumber 
TransPotomac Plaza 5, Charlotte Plaza, 527 Madison Avenue, One Lincoln 
Centre, 200 Galleria and the first mortgage note on Market Square. These 
mortgages total $250.0 million and are interest only with no prepayment 
rights. The first loan has a $65.0 million principal balance, bears interest 
at a rate of 7.28% and matures in October 2000. Upon repayment of this loan, 
PGGM will release the liens on TransPotomac Plaza 5 and Charlotte Plaza. The 
second loan has a $65.0 million principal balance, bears interest at a rate 
of 7.47% and matures in October 2004. Upon repayment of this loan, PGGM will 
release the liens on 527 Madison Avenue and One Lincoln Centre. The third 
loan has a $120.0 million principal balance, bears interest at 7.54% and 
matures in October 2007. Upon repayment of this loan, PGGM will release the 
liens on Market Square and 200 Galleria.

     On December 31, 1997, the Company purchased the second mortgage on Sixty 
State Street in Boston, MA.  The property has a first mortgage in the amount 
of approximately $78.4 million, which matures in January 2005. The loan 
requires amortization based on a 30-year schedule and bears interest at a 
rate of 9.5%. While the face amount of the first mortgage is $77.9 million, 
and the interest rate is 9.5%, the Company is carrying the debt at $88.1 
million, which is the market value of the loan at the time of the closing, 
less the amortization of principal and premium since closing, based upon a 
market interest rate for similar quality loans of 6.84%.

     On January 28, 1998, the Company entered into an $80.0 million first 
mortgage on Corporate 500 Centre with Bankers Trust Company. The loan bears 
interest at a rate of LIBOR plus 1.0% and matures in July 2002.

     On June 3, 1998, the Company assumed the mortgage on 201 California Street 
in San Francisco, CA. The loan requires amortization based on a 30-year 
schedule and bears interest at a rate of 6.9%. While the face amount of the 
loan is $32.8 million, and the interest rate is 6.9%, the Company is carrying 
the debt at $33.2 million, which is the market value of the loan at the time 
of the closing, less the amortization of principal and premium since closing, 
based upon a market interest rate for similar quality loans of 6.7%.


                                    23 of 30

<PAGE>

     On June 3, 1998, the Company assumed the mortgage on Wilshire Palisades 
in Santa Monica, CA. The loan requires amortization based on a 30-year 
schedule and bears interest at a rate of 8.04%. While the face amount of the 
loan is $28.8 million, and the interest rate is 8.04%, the Company is 
carrying the debt at $30.1 million, which is the market value of the loan at 
the time of the closing, less the amortization of principal and premium since 
closing, based upon a market interest rate for similar quality loans of 6.7%.

     On September 25, 1998, the Company completed the refinancing of the 
$96.1 million mortgage on One Norwest Center with CIGNA and Mass Mutual. As a 
result of the refinancing, the principal balance was increased to $98.5 
million, the term of the loan was extended from three years to ten years and 
the interest rate was reduced from 7.50% to 6.90%.

     On October 9, 1998, the Company completed the refinancing of the $80.0 
million mortgage on Corporate 500 Centre with Teachers Insurance and Annuity 
Association. As a result of the refinancing, the principal balance was 
increased to $90.0 million, the term of the loan was extended from 4.5 years 
to 10 years and the interest rate was increased by three basis points to 
6.66%.

Other Indebtedness

     On August 8, 1995, the existing $32.5 million loan (the "Term Loan") was 
extended through December 31, 2003 and assigned to Deutsche Bank AG London at 
an interest rate of 5%. The Term Loan had a $32.5 million balance at December 
31, 1996. The loan was prepaid on March 18, 1997, since, under its terms, it 
was required to be prepaid upon Cornerstone's IPO in the United States. The 
Company has no long-term debt maturing until 2000.

     On October 27, 1997, the Company entered into a three-year, $350.0 
million acquisition line of credit syndicated by Bankers Trust Company and 
The Chase Manhattan Bank. The line bears interest at a rate of LIBOR plus 
1.10% to 1.40% depending on the Company's then current leverage ratio. As of 
September 30, 1998, $148.0 million of the credit line was outstanding at a 
weighted-average interest rate of approximately 6.79%. The line is also 
available for the issuance of standby letters of credit.

Stockholders' and Unitholders' Distributions

     Cornerstone intends to distribute at least 95% of its taxable income to 
maintain its qualification as a REIT. The Company anticipates that FFO will 
exceed taxable income for the foreseeable future. Cornerstone's distribution 
policy is to pay distributions based upon FFO, less prudent reserves. The 
Company paid distributions of $0.30 per share/unit to all stockholders and 
Unitholders on February 27, 1998 (to stockholders and Unitholders of record 
as of January 30, 1998). The Company paid distributions of $0.30 per share/unit
to all stockholders and Unitholders on May 29, 1998 (to stockholders and 
Unitholders of record as of April 30, 1998). The Company paid distributions of 
$0.30 per share/unit to all stockholders and Unitholders on August 31, 1998 (to
stockholders and Unitholders of record as of July 31, 1998).

     At the present time, the Company is current in the payment of all 
preferred dividends.

Liquidity

     At September 30, 1998, the Company had approximately $30.6 million in 
cash and cash equivalents and approximately $5.3 million in restricted cash. 
Restricted cash is being held by the mortgage servicer for the One Norwest 
Center, Washington Mutual Tower and Wilshire Palisades mortgage loans. 
Cornerstone also had available $202.0 million under its working capital line 
of credit for general corporate purposes. In addition, Cornerstone 
anticipates it will receive distributions from its real estate partnerships, 
rental income from its fee owned properties and interest income from its 
mortgages on a monthly basis which will be used to cover normal operating 
expenses and pay distributions to its stockholders and Unitholders. Based 
upon its cash reserves and other sources of funds including its $350.0 
million line of credit, Cornerstone has sufficient liquidity to meet its cash 
requirements for the foreseeable future.

                                    24 of 30

<PAGE>

Other Matters

General
- -------
     The Company is not aware of any environmental issues at any of its 
properties. The Company believes it has sufficient insurance coverage at each 
of its properties. A majority of the Company's leases with the majority of its 
tenants require the tenants to pay most operating expenses and increases in 
common area maintenance expenses, which reduces the Company's exposure to 
increases in costs and operating expenses resulting from inflation.

Recently Issued Accounting Standards 
- ------------------------------------
     During 1998, the Financial Accounting Standards Board issued Statement of 
Financial Accounting Standard No. 133 "Accounting for Derivative Instruments 
and Hedging Activities" ("SFAS 133"), which is effective for fiscal years 
beginning after June 15, 1999. SFAS 133 establishes a new model for 
accounting for derivatives and hedging activities and supersedes and amends a 
number of existing standards. In addition, the Accounting Standards Executive 
Committee of the American Institute of Certified Public Accountants issued 
Statement of Position 98-5, "Reporting on the Costs of Start-Up Activities" 
("SOP 98-5") and Statement of Position 98-1, "Accounting for the Costs of 
Computer Software Developed or Obtained for Internal Use" ("SOP 98-1"), which 
are effective for fiscal years beginning after December 15, 1998. SOP 98-5 
requires that certain costs incurred in conjunction with start-up activities 
be expensed. SOP 98-1 provides guidance on whether the costs of computer 
software developed or obtained for internal use should be capitalized or 
expensed. Management believes that when the Company adopts SFAS 133, SOP 98-5 
and SOP 98-1 they will not have a significant impact on the Company's 
financial statements.

     During the first quarter of 1998, the Company adopted the Emerging 
Issues Task Force of the Financial Accounting Standards Board release Issue 
No. 97-11, "Accounting for Internal Costs Relating to Real Estate Property 
Acquisitions" ("EITF 97-11"). EITF 97-11 requires that the internal 
pre-acquisition costs of identifying and acquiring operating property be 
expensed as incurred. The adoption of EITF 97-11 did not have a material 
impact on the Company's financial statements.

     During the first quarter of 1998, the Company also adopted the Financial 
Accounting Standards Board's Statement of Financial Accounting Standard No. 
130, "Reporting Comprehensive Income" ("SFAS 130"). SFAS 130 specifies the 
presentation and disclosure requirements for comprehensive income which 
includes those items which have been formerly reported as a component of 
stockholders' equity. The adoption of SFAS 130 did not have a significant 
impact on the Company's financial statements.

Year 2000 Issue
- ---------------

     General      

     The Year 2000 Issue is the result of computer programs being written 
using two digits rather than four to define a specific year. Absent 
corrective actions, a computer program that has date sensitive software may 
recognize a date using "00" as the year 1900 rather than the year 2000. This 
could result in a system failure or miscalculations causing disruptions of 
operations, including, among other things, a temporary inability to process 
transactions, prepare financial statements, send tenant invoices, or engage 
in similar normal business activities.

     Readiness

     The Company's corporate business and technical information systems have 
been assessed as to Year 2000 compliance and functionality. Presently these 
systems are nearly complete with respect to required software or hardware 
changes. The Company anticipates that internal business and technical 
information Year 2000 compliance issues will be substantially remediated by 
the end of the second quarter of 1999.

     The Company has completed the identification and review of computer 
hardware and software suppliers and is in the process of verifying the Year 
2000 preparedness of third party property managers, suppliers, tenants, 
vendors and/or service providers that the Company has identified as critical.

                                    25 of 30

<PAGE>

     Cost

     The total historical and anticipated remaining costs for the Year 2000 
remediation are estimated to be immaterial to the Company's financial 
condition. The costs to date have been expensed as incurred and consist of 
immaterial internal staff costs and other expenses such as telephone and 
mailing costs. In addition, where the appropriate course of action includes 
replacement or upgrade of certain systems or equipment, the Company's review 
at this time indicates a minor cost to the Company. The "non-information 
technology building systems" that have thus far been identified as 
non-compliant are at or approaching the end of their useful lives and have 
been or will be replaced or upgraded in 1999 as a part of the normal 
operations and maintenance at the Company's properties.

     The Company does not anticipate delays in finalizing Year 2000 
remediation within remaining time schedules. However, third parties having a 
material relationship with the Company (e.g., property managers, utilities, 
financial institutions, governmental agencies, municipalities and major 
tenants) may be a potential risk based on their individual Year 2000 
preparedness which may not be within the Company's reasonable control. The 
Company is in the process of identifying, reviewing and logging the Year 2000 
preparedness of critical third parties.

     Anticipated completion of this review is December 31, 1998. Pending the 
results of that review, the Company will determine what course of action and 
contingencies will need to be made. There can be no assurance that the 
external Year 2000 issues will be resolved in 1999. If not resolved, such 
issues could have a material adverse impact on the Company's business, 
operating results and financial condition.

     Year 2000 Compliance Detail

     The Company's program addresses the Year 2000 issue with respect to the 
following: (i) the Company's information technology and operating systems, 
including its accounting and financial reporting systems; (ii) the Company's 
"non-information technology building systems", including building access, 
energy management, elevator systems, equipment and other infrastructure 
systems that may contain or use computer systems or embedded micro-controller 
technology; and (iii) certain systems of the Company's third party property 
managers, major suppliers and material service providers (insofar as such 
systems relate to the Company's business activities such as billing, 
financial reporting, payroll, health services, stock transfer services and 
alarm systems). As described below, the Company's Year 2000 program involves 
(a) an assessment of the Year 2000 problems that may affect the Company, (b) 
the development of remedies to address the problems discovered in the 
assessment phase, (c) the testing of such remedies and (d) the preparation of 
contingency plans to deal with worst case scenarios.

         Assessment Phase. As part of the internal assessment phase, the Company
has attempted to substantially identify all the major components of the systems
described above. In determining the extent to which such systems are vulnerable
to the Year 2000 issue, the Company is evaluating either directly or through its
third party managers purchased software applications and property operational
control systems, e.g., heating ventilation and air conditioning (HVAC), lighting
timers, alarms, fire, sewage and access. In addition, in the second quarter of
1998, the Company's third party managers began sending letters to the major
suppliers and service providers of the Company's buildings, requesting them to
provide assurance of existing or anticipated Year 2000 compliance by their
systems insofar as the systems relate to their activities with the Company. The
Company is requesting that all responses to the inquiries be returned to it no
later than December 31, 1998.

         Remediation and Testing Phase. Based upon the assessment and
remediation efforts to date, the Company has completed, tested and put on line
the Year 2000 compliance modification in all the software for all corporate
applications including accounting and financial reporting. All of the Company's
personal computers and associated applications and networking infrastructure are
Year 2000 compliant.


                                    26 of 30

<PAGE>

         The Company purchases primarily "off-the-shelf" versions of the
software used for spreadsheet analysis, database applications, word processing
systems and accounting, all of which are Year 2000 compliant. The Company's
corporate office phone, communication and data processing networks are Year 2000
compliant.

         Seven third-party property managers manage the Company's portfolio of
21 office properties. The Company is working closely with these managers to
assess the Year 2000 impact on the operations of the buildings. For the most
part, the systems reviewed by the Company have been found to be Year 2000
compliant. The reviewed systems include but are not limited to HVAC equipment,
building management systems, elevators, security and life safety systems. Those
systems that have been found not to be compliant are nearing the end of their
useful lives and are being replaced or upgraded in the normal course of
business.

         Contingency Plans. The Company intends to develop contingency plans to
handle its most reasonably likely worst case Year 2000 scenarios. These have not
yet been identified fully. The Company intends to complete its determination of
worst case scenarios after it has received and analyzed responses to
substantially all of the inquiries it has made of third parties. Following its
analysis, the Company intends to develop a timetable for completing its
contingency plans.

         Costs Related to the Year 2000 Issue. To date, the Company has 
incurred no material costs. Labor, mailing and phone costs attributed to the 
Year 2000 program are minimal. The Company currently estimates that to have 
all systems compliant it will incur some additional costs which are not 
quantifiable but believed to be not material to the Company's business. The 
"non-information technology building systems" that have thus far been 
identified as non-compliant and at or approaching the end of their useful 
lives will be replaced or upgraded as a part of the normal operations and 
maintenance at the Company's properties.

         Risks Related to the Year 2000 Issue. Although the Company's Year 2000
efforts are intended to minimize the adverse effects of the Year 2000 issue on
the Company's business and operations, the actual effects of the issue and the
success or failure of the Company's efforts described above cannot be known
until the year 2000. Failure by the Company's third party managers, major
suppliers, and other service providers to address adequately their respective
Year 2000 issues in a timely manner (insofar as such issues relate to the
Company's business) could have a material adverse effect on the Company's
business, results of operations and financial condition.

Wilson Acquisition
- ------------------
     On June 22, 1998, the Company entered into an agreement to merge 
with and acquire certain assets from Wilson, a private real estate developer, 
property manager and owner based in San Mateo, California. The Company will 
acquire the Wilson operating company and approximately 9.1 million square 
feet of Wilson's Class A office buildings in the San Francisco Bay Area, 
Southern California, Phoenix, Salt Lake City and Seattle. The total purchase 
price for Wilson and its portfolio is expected to be approximately $1.81 
billion. At this price, it is anticipated that the Company will issue to 
Wilson and its investors approximately $635 million in Common Stock and 
UPREIT Units, at a stated price of $17.25 per share/unit, and pay cash for 
the remaining equity. In addition, the Company will assume or repay 
approximately $780 million of existing indebtedness currently held by Wilson. 
The cash needed for the transaction will be financed under the Revolving 
Credit Facility and from an expected sale of $200 million of Common Stock to 
PGGM, a 31% equity holder in the Company at September 30, 1998, at an agreed 
price of $17.25 per share. The consummation of the Wilson Acquisition is 
subject to the approval of the stockholders of the Company and the investors 
of Wilson, as well as other outstanding closing conditions. The Wilson 
investors consented to the transaction in September 1998. The Company's proxy 
statement has been filed and distributed to its stockholders. Upon approval 
of the transaction by the Company's stockholders, the transaction will close 
in the fourth quarter of 1998.

                                    27 of 30

<PAGE>

Minneapolis Office Building Development
- ---------------------------------------
     The Company has entered into an agreement to purchase a 912,000 square 
foot Class A office building, currently under development, in downtown 
Minneapolis, Minnesota, for an estimated cost of approximately $160.0 
million, of which approximately $33.0 million has been spent to date. The 
project is scheduled to be completed in the year 2000 and is approximately 
50% pre-leased. The development is to be financed through a construction loan 
by U.S. Bank. Upon completion, the Company will retire the construction loan 
and acquire the property from the developer for an amount to be determined by 
applying a negotiated formula to in-place net operating income.

Subsequent Events

     1. A cash dividend and Unitholder distribution of $0.30 per share was 
declared for the fourth quarter of 1998 to Common Stockholders and 
Unitholders of record as of October 30, 1998, to be paid on November 30, 1998.

     2. On November 4, 1998, a syndicate of banks led by BT Alex. Brown, 
Chase Securities, and NationsBank Montgomery Securities provided the Company 
with a $550 million line of credit for acquisitions and general working 
capital purposes. The interest rate on the line of credit depends on the 
Company's leverage ratio at the time of borrowing and will be at a spread of 
1.10% to 1.40 % over LIBOR. These are the same terms as the Company's 
previous $350 million line of credit, which was retired at the closing of the 
new line of credit. The $550 million line of credit expires on November 4, 
2001. On November 4, 1998, the amount outstanding on the previous line of 
credit was transferred to the banks taking part in the syndicate providing 
the new line of credit.

     3. On November 6, 1998, the Company purchased an additional 14.29% 
partnership interest in MSA for $4.0 million. Upon completion of the 
transaction, the Company effectively owns 99.14% of the MSA entity, which has 
a 70% interest in AALP. AALP owns and operates Market Square. The Company 
will consolidate Market Square in the fourth quarter.


                                      28 of 30

<PAGE>

                           PART II - OTHER INFORMATION

Item 2. CHANGES IN SECURITIES AND USE OF PROCEEDS

On August 31, 1998, through a dividend reinvestment plan available to all German
shareholders, the Company issued 94,610 shares of Common Stock to such
shareholders in lieu of paying cash dividends in the aggregate amount of
$1,476,000. Such shares were issued and sold to persons outside the United
States and were not registered under the Securities Act.



Item 6.   EXHIBITS AND REPORTS ON FORM 8-K

(a)  Exhibits: 


     1)   Exhibit 2.1: Contribution Agreement and Agreement and Plan of Merger
          dated as of June 22, 1998 (incorporated by reference to Annex A to 
          the Company's Proxy Statement filed with the Commission on 
          November 13, 1998)

     2)   Exhibit 12.1: Statement of Computation of Earnings to Fixed Charges

     3)   For EDGAR filing purposes only, this report contains Exhibit 27,
          Financial Data Schedule

     4)   Exhibit 99.1: Supplemental Information to Quarterly Earnings Release

(b)  Reports on Form 8-K:

     1.   Form 8-K dated August 26, 1998

          Item 2 - Acquisition or Disposition of Assets. Press releases
                              announcing Cornerstone's acquisition of One 
                              Memorial Drive, 201 California and Wilshire 
                              Palisades.

          Item 7 - Financial Statements and Exhibits. Income statements for One
                              Memorial Drive, 201 California and Wilshire 
                              Palisades, and financial statements reflecting 
                              the acquisition of same.

     2.   Form 8-K/A dated September 4, 1998

          Item 7 - Financial Statements and Exhibits. Consents of Independent
                              Auditors to include their opinions in various 
                              previously filed Cornerstone registration 
                              statements and reports.





                                     29 of 30

<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.


                              CORNERSTONE PROPERTIES INC.
                              (Registrant)


                              By: /s/ John S. Moody                          .
                                  --------------------------------------------
                                  John S. Moody, Chairman and CEO

                              Date:  November 16, 1998

                              By: /s/ Kevin P. Mahoney                       .
                                  --------------------------------------------
                                  Kevin P. Mahoney, Senior Vice President 
                                        and Chief Financial Officer
                                        (Principal Financial Officer)

                              Date:  November 16, 1998



                                        30 of 30

<PAGE>

                                                                    Exhibit 12.1
                                                        
   Statement of Computation of Earnings to Fixed Charges and Preferred Stock
 Dividend Requirements for the nine month periods ended September 30, 1998 and
                               September 30, 1997

<TABLE>
<CAPTION>

                                                  For the nine months ended
                                           September 30, 1998    September 30, 1997
                                           ------------------    ------------------
<S>                                            <C>                   <C>     
Net income .............................       $ 60,964              $ 21,666
Interest expense .......................         47,724                22,395
                                               --------              --------
Earnings before interest ...............        108,688                44,061
                                                                 
Interest expense .......................         47,724                22,395
Preferred dividends ....................          2,625                 9,285
                                               --------              --------
Fixed charges ..........................         50,349                31,680
                                                                 
Earnings to fixed charges and preferred                          
     stock dividend requirements .......           2.16                  1.39
                                               --------              --------
                                               --------              --------
                                                          
</TABLE>

<TABLE> <S> <C>

<PAGE>
<ARTICLE> 5
<MULTIPLIER> 1,000
       
<S>                             <C>
<PERIOD-TYPE>                   9-MOS
<FISCAL-YEAR-END>                          DEC-31-1998
<PERIOD-START>                             JAN-01-1998
<PERIOD-END>                               SEP-30-1998
<CASH>                                          30,566
<SECURITIES>                                         0
<RECEIVABLES>                                   58,906
<ALLOWANCES>                                         0
<INVENTORY>                                          0
<CURRENT-ASSETS>                                45,842
<PP&E>                                       2,169,806
<DEPRECIATION>                                 271,218
<TOTAL-ASSETS>                               2,535,578
<CURRENT-LIABILITIES>                           46,548
<BONDS>                                              0
                                0
                                     50,000
<COMMON>                                     1,356,615
<OTHER-SE>                                     (1,978)
<TOTAL-LIABILITY-AND-EQUITY>                 2,535,578
<SALES>                                              0
<TOTAL-REVENUES>                               257,084
<CGS>                                                0
<TOTAL-COSTS>                                  186,845
<OTHER-EXPENSES>                                 7,006
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                              47,724
<INCOME-PRETAX>                                 60,964
<INCOME-TAX>                                         0
<INCOME-CONTINUING>                             60,964
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                  2,269
<CHANGES>                                            0
<NET-INCOME>                                    60,964
<EPS-PRIMARY>                                     0.59
<EPS-DILUTED>                                     0.59
        

</TABLE>

<PAGE>

                                                                    Exhibit 99.1


                           Cornerstone Properties Inc.


             Supplemental Information to Quarterly Earnings Release




1)   Third Quarter 1998

     -    Balance Sheet

     -    Income Statement

2)   Third Quarter Press Release

3)   Quarterly Fact Sheet

4)   Table of Properties

5)   Top Ten Tenants Schedule

6)   Historical Occupancy Schedule

7)   Net Rent and Net Effective Rent Schedule

8)   Lease Expiration Schedule

9)   Tenant Retention Schedule

10)  Leasing Costs and Capital Expenditures

11)  Debt Schedule

12)  Equity Schedule

13)  Minority Sharing in Cash Flows and Residual Proceeds


<PAGE>


                           Cornerstone Properties Inc.





                           Supplemental Information to

                           Quarterly Earnings Release





                              - Third Quarter 1998

                                - Balance Sheet

                                - Income Statement


<PAGE>

<TABLE>

                                  CORNERSTONE PROPERTIES INC. AND SUBSIDIARIES
                                   CONDENSED CONSOLIDATED BALANCE SHEETS
                             (Dollar amounts in thousands, except per share amounts)

<CAPTION>
                                                                                  September 30,    December 31,
                                                                                      1998            1997
                                                                                   -----------     -----------
                                                                                   (Unaudited)
<S>                                                                                <C>             <C>        
ASSETS
Investments, at cost:
       Land                                                                        $   315,498     $   260,542
       Buildings, leasehold interests and improvements                               1,854,308       1,559,085
       Investment in real estate joint venture                                         245,784         240,253
       Deferred lease costs                                                            140,638         127,645
                                                                                   -----------     -----------
                                                                                     2,556,228       2,187,525
       Less: Accumulated depreciation and amortization                                 271,218         229,652
                                                                                   -----------     -----------
          Total investments                                                          2,285,010       1,957,873
                                                                                
Cash and cash equivalents                                                               30,566          24,730
Restricted cash                                                                          5,250           1,903
Other deferred costs, net of accumulated amortization of $3,015 and $1,998             145,726           5,728
Deferred tenant receivables                                                             48,352          38,531
Tenant and other receivables, net                                                       10,026           7,584
Notes receivable                                                                           528           1,652
Other assets                                                                            10,120          13,480
                                                                                   -----------     -----------
Total Assets                                                                       $ 2,535,578     $ 2,051,481
                                                                                   -----------     -----------
                                                                                   -----------     -----------
LIABILITIES

Long-term debt, inclusive of $11,799 and $11,209 of unamortized premium            $   849,554     $   706,178
Credit facility                                                                        148,000         187,000
Accrued interest payable                                                                 7,261           4,134
Accrued real estate taxes payable                                                       19,446          13,401
Accounts payable and accrued expenses                                                   19,841          18,363
Unearned revenue and other liabilities                                                  16,770          10,986
                                                                                   -----------     -----------
Total Liabilities                                                                    1,060,872         940,062
                                                                                   -----------     -----------
MINORITY INTEREST

Minority Interest in operating partnership                                              55,258            --
Minority Interest in real estate joint ventures                                         14,811          15,420
                                                                                   -----------     -----------
Total Minority Interest                                                                 70,069          15,420


Commitments and Contingencies

Redeemable Preferred Stock; 344,828 shares authorized;
   0 shares issued and outstanding                                                        --              --

STOCKHOLDERS' INVESTMENT
7% Cumulative Convertible Preferred Stock, $16.50 stated value;
   65,000,000 shares authorized; 3,030,303 shares issued and outstanding                50,000          50,000
Common stock, no par value; 250,000,000 shares authorized;
   (1998-101,636,864; 1997-83,191,819) shares issued and outstanding
Paid-in capital                                                                      1,356,615       1,048,187
Deferred compensation                                                                   (1,978)         (2,188)
                                                                                   -----------     -----------
Total Stockholders' Investment                                                       1,404,637       1,095,999
                                                                                   -----------     -----------
Total Liabilities and Stockholders' Investment                                     $ 2,535,578     $ 2,051,481
                                                                                   -----------     -----------
                                                                                   -----------     -----------

</TABLE>

                          The accompanying notes are an integral part of these
                              condensed consolidated financial statements.


<PAGE>

<TABLE>

                              CORNERSTONE PROPERTIES INC. AND SUBSIDIARIES
                              CONDENSED CONSOLIDATED STATEMENTS OF INCOME
                       FOR THE THREE AND NINE MONTHS ENDED SEPTEMBER 30, 1998 AND 1997
                           (Dollar amounts in thousands, except per share amounts)
                                                 (Unaudited)

<CAPTION>


                                                   Three Months   Three Months   Nine Months    Nine Months
                                                      Ended          Ended          Ended          Ended
                                                   September 30,  September 30,  September 30,  September 30,
                                                       1998           1997          1998           1997
                                                   -------------  -------------  -------------  -------------
                                                                                        
<S>                                                  <C>           <C>            <C>            <C>  
Revenues    
       Office and parking rentals                    $  83,227     $  34,546     $ 239,767     $ 103,237
       Earnings in real estate joint venture             3,856          --          10,150          --
       Interest and other income                         1,955         3,868         7,167         8,432
                                                     ---------     ---------     ---------     ---------
           Total Revenues                               89,038        38,414       257,084       111,669
                                                     ---------     ---------     ---------     ---------
Expenses
       Building operating expenses                      18,896         7,660        52,947        22,693
       Real estate taxes                                12,034         5,933        34,900        17,553
       Interest expense                                 16,057         7,405        47,724        22,395
       Depreciation and amortization                    15,702         7,057        42,561        20,865
       General and administrative                        3,169         1,869         8,713         5,134
                                                     ---------     ---------     ---------     ---------
           Total Expenses                               65,858        29,924       186,845        88,640
                                                     ---------     ---------     ---------     ---------
                                                        23,180         8,490        70,239        23,029
                                                     ---------     ---------     ---------     ---------
Other income (expenses)
      Loss on sale of real estate assets                  (127)         --          (2,324)         --
      Minority interest                                 (1,826)         (414)       (4,682)       (1,408)
      Net gain on interest rate swaps                     --            --            --              99
                                                     ---------     ---------     ---------     ---------
Income before extraordinary item                        21,227         8,076        63,233        21,720

Extraordinary loss                                      (2,269)         --          (2,269)          (54)
                                                     ---------     ---------     ---------     ---------
Net income                                           $  18,958     $   8,076     $  60,964     $  21,666
                                                     ---------     ---------     ---------     ---------
                                                     ---------     ---------     ---------     ---------
Income applicable to preferred stock                 $    (875)    $    (875)    $  (2,625)    $  (9,285)
                                                     ---------     ---------     ---------     ---------
                                                     ---------     ---------     ---------     ---------
Income applicable to common stock                    $  18,083     $   7,201     $  58,339     $  12,381
                                                     ---------     ---------     ---------     ---------
                                                     ---------     ---------     ---------     ---------
Income before extraordinary item per
 common share                                        $    0.20     $    0.16     $    0.62     $    0.37
                                                     ---------     ---------     ---------     ---------
                                                     ---------     ---------     ---------     ---------
Extraordinary loss per common share                  $   (0.02)    $    --     $     (0.02)    $   --
                                                     ---------     ---------     ---------     ---------
                                                     ---------     ---------     ---------     ---------
Basic income per common share                        $    0.18     $    0.16     $    0.59     $    0.37
                                                     ---------     ---------     ---------     ---------
                                                     ---------     ---------     ---------     ---------
Diluted income per common share                      $    0.18     $    0.16     $    0.59     $    0.37
                                                     ---------     ---------     ---------     ---------
                                                     ---------     ---------     ---------     ---------                           
</TABLE>

                          The accompanying notes are an integral part of these
                             condensed consolidated financial statements.


<PAGE>


                           Cornerstone Properties Inc.



                           Supplemental Information to

                           Quarterly Earnings Release





                         - Third Quarter Press Release


<PAGE>

FOR IMMEDIATE RELEASE
November 3, 1998

FOR ADDITIONAL INFORMATION, CONTACT:

Kevin Mahoney                            Karin Maas
Chief Financial Officer                  VP, Investor Relations
(212) 605-7142                           (212) 605-7113


                           CORNERSTONE PROPERTIES INC.
                      ANNOUNCES THIRD QUARTER 1998 RESULTS


Third Quarter 1998 Highlights

- -    Announced approval by the investors of William Wilson and Associates of a
     merger valued at over $1.81 billion.
 
- -    Funds from Operations per share increased over 24% as compared to the same
     period in 1997.

- -    Occupancy rate remained a solid 98%.

- -    Completed the refinancing of One Norwest Center in Denver and Corporate 500
     Centre in Deerfield, Illinois.

New York, NEW YORK (November 3, 1998) -- Cornerstone Properties Inc. (NYSE:
CPP), a real estate investment trust, announced today results for its third
quarter ended September 30, 1998. Funds from operations (FFO) allocated to
shareholders amounted to $39,396,000, or $0.36 per share calculated on
109,931,000 average diluted total shares outstanding, compared to $15,371,000,
or $0.29 per share on 53,145,000 average diluted total shares outstanding for
the three months ended September 30, 1997. The increase in FFO per share was due
to the accretive impact of the Company's acquisitions over the past twelve
months and internal growth. As defined by NAREIT, funds from operations is net
income excluding expenses from debt restructuring, gains (or losses) on sale of
property, plus depreciation and amortization.

Year-to-date net operating income before depreciation from Cornerstone
Properties' real estate assets increased 163% to $165,624,000 for the nine
months ended September 30, 1998, from $62,991,000 for the comparable period in
1997.

Net income for the third quarter of 1998 grew to $18,958,000 compared to
$8,076,000 in the third quarter of 1997. Year-to-date net income increased to
$60,964,000 compared to $21,666,000 for 1997.

John S. Moody, Chairman and CEO said, "Cornerstone Properties' third quarter
results continue to reflect the advantages that flow from our very high quality
portfolio - namely high occupancy, high retention and same store revenue 
growth reflecting good market fundamentals in our portfolio."


<PAGE>

Cornerstone Properties Announces Third Quarter 1998 Earnings
November 3, 1998
Page 2


Quarterly Dividend Declared

The Company declared a quarterly dividend of $0.30 per share payable on November
30, 1998 to shareholders of record as of October 30, 1998.

"Same Store" Revenue Growth Continues

The Company achieved year to date "same store" net operating income growth of
3.51% over 1997 at the seven properties owned over the same period; this is a
substantial increase in same store growth and the highest quarterly increase
since Cornerstone became a public company in early 1997. This increase is due to
a 2.48% increase in revenues while expenses increased only 0.81% and reflects
the strengthening of fundamentals in the Company's core markets.

Leasing Update: Tenant Retention Rate 77% and Overall Occupancy Rate 98%

Tenant retention for 1998 decreased to 77%, mainly due to the downsizing of an
existing tenant's lease, however, since the space which was vacated was
immediately leased to a new tenant, there was no loss of revenue from the
downsizing. The portfolio's overall occupancy rate remained at 98%. Occupancy
across the DIHC portfolio has increased from 96% to 98%, in the eleven months
since it was acquired.

Two significant leasing transactions were completed at Sixty State Street in
Boston. Cornerstone repurchased 44,000 square feet of space that was leased to
ITT Sheraton at substantially below market rents. The Company expects to
re-lease this space at market rates. In addition, the law firm, Hale and Dorr
exercised an option to take an additional 23,000 square feet in the building.

Cornerstone Properties also signed a lease for 60,000 square feet with Towers
Perrin, renewing and expanding their tenancy at 500 Boylston Street which will
significantly reduce 1999 expirations.

Refinancing of One Norwest Center in Denver and Corporate 500 Centre in
Deerfield

During the third quarter and early fourth quarter the Company refinanced the
first $96.1 million mortgage on One Norwest Center in Denver with CIGNA and Mass
Mutual. The Company increased its proceeds by approximately $2 million to $98.5
million. The term of the loan was extended from three years to ten years and the
interest rate was reduced from 7.50% to 6.90%.

In the early part of the fourth quarter the company also refinanced the first
mortgage on Corporate 500 Centre in Deerfield, Illinois with Teachers Insurance
and Annuity Association. The outstanding balance was increased from $80 million
to $90 million. The term of the loan was extended from 4.5 years to 10 years and
the interest rate increased by three basis points to 6.66%.

Approval of Merger with William Wilson and Associates

On September 14, 1998 the Company announced that the investors of William Wilson
and Associates had approved the merger with Cornerstone Properties. Since then
Cornerstone's proxy has been filed and is being reviewed by the Securities and
Exchange Commission. Cornerstone Properties expects the transaction to close in
December.


<PAGE>

Cornerstone Properties Announces Third Quarter 1998 Earnings
November 3, 1998
Page 3

Cornerstone Properties Inc. is a self-administered equity real estate investment
trust (REIT) investing in Class A office properties in prime locations in major
metropolitan areas and central business districts. The Company, through its
subsidiaries, currently owns 21 Class A office properties throughout the United
States totaling approximately 11.5 million square feet. Headquartered in New
York City, Cornerstone's stock is traded on the New York Stock Exchange under
the ticker symbol CPP.

This press release contains forward-looking statements within the meaning of the
Federal securities laws. Forward-looking statements are inherently subject to
risks and uncertainties, many of which cannot be predicted with accuracy, that
could cause the actual results, performance or achievements of Cornerstone and
Wilson to differ materially from those reflected in such forward-looking
statements. The acquisition described herein may not be consummated for a
variety of reasons and anticipated benefits may not materialize, also for a
variety of reasons. Information contained in this press release regarding
current and future market conditions is based on Cornerstone's and Wilson's
assessment of real estate markets as of this date and is subject to the
uncertainties inherent in such an assessment. In particular, but not
exclusively, national and regional economic conditions, the rate of new
construction, and demand and supply in a given market will affect leasing
activity, projected rents and the cost of lease renewals.

                               [Tables to follow]
                                      # # #

  For more information on Cornerstone Properties visit Cornerstone Properties'
                     Web site at http://www.cstoneprop.com


<PAGE>

Cornerstone Properties Announces Third Quarter 1998 Earnings
November 3, 1998
Page 4



                                       CORNERSTONE PROPERTIES INC.
                                          Funds From Operations
                                           September 30, 1998
                                    (in 000's, except per share data)

<TABLE>
<CAPTION>
                                                     Three months Ended       Nine months Ended
                                                        September 30             September 30
                                                     1998          1997        1998          1997
                                                    -------       ------      -------       ------
<S>                                                 <C>          <C>          <C>          <C>    
Rental Income1                                       90,897       34,546      259,992      103,237
Building Operating Expenses1                         33,364       13,593       94,368       40,246
                                                    -------       ------      -------       ------
Building Net Operating Income                        57,533       20,953      165,624       62,991
                                                    -------       ------      -------       ------
Corporate General and Administrative                 (3,169)      (1,869)      (8,713)      (5,134)
Interest and Other Income                             1,955        3,868        7,167        8,432
                                                    -------       ------      -------       ------
EBITDA                                               56,319       22,952      164,078       66,289
                                                    -------       ------      -------       ------
Interest Expense                                    (16,057)      (7,405)     (47,724)     (22,395)
Minority Adjustments                                 (1,453)        (721)      (4,671)      (2,452)
Rent Notes                                              387          346        1,133          903
                                                    -------       ------      -------       ------
Funds From Operations                                39,196       15,172      112,816       42,345
Interest on Convertible Debt                            200          199          604          592
                                                    -------       ------      -------       ------
Funds From Operations (Adjusted for
 Convertible Debt                                    39,396       15,371      113,420       42,937
                                                    -------       ------      -------       ------
Weighted Average Diluted Shares                     109,931       53,145      104,940       46,404
FFO Per Share (Diluted)                                0.36         0.29         1.08         0.93
Less: Capital Expenditures Per Share                   0.02         0.02         0.05         0.06
                                                    -------       ------      -------       ------
AFFO Per Share                                         0.34         0.27         1.03         0.87
                                                    -------       ------      -------       ------


Funds From Operations                                39,196       15,172      112,816       42,345
Less: Preferred Dividends                              (875)        (875)      (2,625)      (9,285)
Less: Recurring Lease Costs and
  Capital Expenditures2                              (2,062)      (1,038)      (5,690)      (2,999)
  Less: Straight Line Rents Adjusted For
        Minority Interest                            (3,483)          38      (10,392)        (746)
                                                    -------       ------      -------       ------
Funds Available for Distribution                     32,776       13,297       94,109       29,315
                                                    -------       ------      -------       ------
Weighted Average Common Shares and
  Units Outstanding                                 105,720       45,804      100,729       33,494
Funds Available for Distribution Per Share             0.31         0.29         0.93         0.88
Distribution Per Share                                 0.30         0.30         0.90         0.90

</TABLE>

1.   For the nine months ended September 30, 1998 rental income has been
     increased by $20,225,000 and building operating expenses have been
     increased by $6,521,000 in order to show the effects of Market Square had
     the property been consolidated. For the three months ended September 30,
     1998, rental income has been increased by $7,670,000 and building operating
     expenses have been increased by $2,434,000.

2.   Based on a five year 1994-1998 average of recurring (non-revenue
     generating) tenant leasing costs of $8.46 per square foot leased times the
     five year (1998-2003) average quarterly lease expiration (adjusted for
     minority interest) of 211,009 square feet ($1,785,136) plus a capital
     expenditure reserve (adjusted for minority interest) of $0.10 per square
     foot ($276,717).

Year to date the Company has incurred $12,288,520 in recurring tenant costs in
leasing 1,319,315 square feet or a cost of $9.31 per square foot.

Year to date the Company has incurred $1,179,978 in recurring capital costs or
$0.15 per square foot on an annualized basis.


<PAGE>


                           Cornerstone Properties Inc.



                           Supplemental Information to

                           Quarterly Earnings Release




                             - Quarterly Fact Sheet


<PAGE>

                          Cornerstone Properties Inc.
                              Quarterly Fact Sheet

<TABLE>
<CAPTION>

1998 Common Dividends                         Record Date     Payment Date 
- ---------------------                         -----------     ------------ 
<S>                                            <C>             <C>        
4th Quarter                                    10/30/98        11/30/98
1st Quarter 1999                                1/29/99         2/26/99
2nd Quarter 1999                                4/30/99         5/31/99
3rd Quarter 1999                                7/30/99         8/31/99
- ------------------------------------------    -----------     ------------
Earnings Release/Quarterly Conference Call
- ------------------------------------------
4th Quarter                                     2/25/99
1st Quarter 1999                                 5/4/99
2nd Quarter 1999                                 8/3/99
3rd Quarter 1999                                11/2/99

<CAPTION>

                                                   Quarter to Date                  Year to Date
3rd Quarter Results                              1998            1997           1998            1997
- ------------------------------------------  -----------     -----------      -----------     -----------
<S>                                         <C>             <C>              <C>             <C>        
FFO Per Share                               $      0.36     $      0.29      $      1.08     $      0.93
AFFO Per Share                              $      0.34     $      0.27      $      1.03     $      0.87
FAD Per Share                               $      0.31     $      0.29      $      0.93     $      0.88
FFO Payout Ratio                                     83%            103%              83%             97%
AFFO Payout Ratio                                    88%            111%              87%            103%
FAD Payout Ratio                                     97%            103%              97%            102%
Same Store NOI Growth                                NA              NA             3.51%           1.24%
EBITDA Interest Coverage                           3.46            3.04             3.39            2.90
Fixed Charge Coverage                              3.28            2.72             3.21            2.05
- ------------------------------------------  -----------     -----------      -----------     -----------
Recurring Leasing Costs
 (Adjusted for minority interest)           $ 6,792,320     $ 2,169,613      $12,288,520     $ 6,320,021
Per Square Foot Leased                      $     21.24     $      9.69      $      9.31     $      7.18

Recurring Capital Expenditures              $   689,607     $   205,511      $ 1,179,978     $   267,151
Non-Recurring Leasing Cost                  $   157,355     $   111,981      $ 2,855,217     $   965,173
Non-Recurring Capital Expenditures          $   214,472     $    78,618      $   488,056     $   153,007
- ------------------------------------------  -----------     -----------      -----------     -----------

- ------------------------------------------  -----------     -----------      -----------     -----------
Parking Revenues (included in
 Office and Parking)                        $ 5,218,807     $ 1,396,725      $15,194,491     $ 4,579,374
Parking Expense (included in
 Building Operating Expense)                $   732,710     $    89,694      $ 2,098,710     $   549,041
Net Parking Income                          $ 4,486,097     $ 1,307,031      $13,095,781     $ 4,030,333
- ------------------------------------------  -----------     -----------      -----------     -----------

- ------------------------------------------  -----------     -----------      -----------     -----------
Straight Line Rents                         $ 3,483,000     $   (38,340)     $10,392,000     $   746,429
- ------------------------------------------  -----------     -----------      -----------     -----------

</TABLE>

<PAGE>


                           Cornerstone Properties Inc.





                           Supplemental Information to

                           Quarterly Earnings Release






                              - Table of Properties


<PAGE>

                                                     Cornerstone Properties Inc.
                                                         Table of Properties
                                                       As of September 30, 1998
<TABLE>
<CAPTION>
                                                                                       Remaining
                                                                                        Average
                                            Company's    Total                 Number    Lease
       Property Name              Year       Percent    Rentable    Occupancy    of       Term              Largest
       and Location            Constructed  Interest   Square Feet     Rate    Leases  (in Years)           Tenant
- -----------------------------  -----------  ---------  -----------  ---------  ------  ----------  ------------------------------
<S>                            <C>            <C>      <C>             <C>      <C>       <C>      <C>
One Norwest Center                1983        100%      1,188,000       97%      47        7.9     Norwest Bank Denver N.A.
  Denver, Colorado                                                                                 Newmont Gold Company
                                                                                                   Teletech, Inc.

Norwest Center(1)                 1988         50%      1,118,000       99%      31       11.2     Norwest Corporation
  Minneapolis, Minnesota                                                                           Faegre & Benson
                                                                                                   KPMG Peat Marwick 

Washington Mutual Tower(2)(3)     1988         50%      1,155,000       99%      89        6.0     Perkins Coie
  Seattle, Washington                                                                              Washington Mutual
                                                                                                   Karr Tuttle Campbell

125 Summer Street                 1989        100%        464,000       99%      26        4.0     Deloitte & Touche
  Boston, Massachusetts                                                                            BTM Capital Corp.
                                                                                                   Burns & Levinson

Tower 56(4)                       1983        100%        162,000       99%      44        3.0     Cornerstone Properties
  New York, New York                                                                               ICC Associates, L.P.
                                                                                                   United Bank of Kuwait

One Lincoln Centre                1986        100%        297,000       91%      41        2.4     Superior Bank FSB
  Oakbrook Terrace, IL                                                                             Microsoft Corporation
                                                                                                   McDonald's Corporation

527 Madison Avenue                1986        100%        216,000      100%      20        4.9     The Sumitomo Trust & 
 New York, NY                                                                                       Banking Co., Ltd.
                                                                                                   W.P. Stewart Co., Inc.
                                                                                                   Hill Samuel New York, Inc.

191 Peachtree Street(5)(6)        1991         80%      1,221,000       97%      34        7.8     Wachovia Bank
  Atlanta, Georgia                                                                                 King & Spalding
                                                                                                   Powell, Goldstein, Frazer 
                                                                                                     & Murphy

Market Square(5)(7)               1990         60%        689,000       95%      47        6.9     Fulbright & Jaworski
  Washington, D.C.                                                                                 Edison Electric Institute
                                                                                                   Shearman & Sterling

500 Boylston Street(5)(8)         1988       91.5%        715,000      100%      14        5.7     Massachusetts Financial 
 Boston, Massachusetts                                                                              Services
                                                                                                   The New England Life
                                                                                                   Towers Perrin Forster &  
                                                                                                     Crosby, Inc.

222 Berkeley Street(5)(8)         1991       91.5%        531,000      100%      28        6.4     Houghton Mifflin
  Boston, Massachusetts                                                                            Saga International Holidays
                                                                                                   Oracle Corporation

Charlotte Plaza(5)                1982        100%        613,000       98%      42        6.3     First Union
  Charlotte, North Carolina                                                                        Parker Poe
                                                                                                   Midrex

200 Galleria(5)                   1985        100%        433,000       94%      56        3.4     Liberty Mutual Group
  Atlanta, Georgia                                                                                 Worldspan
                                                                                                   Cobank ACB

11 Canal Center(5)                1986        100%         70,000       96%       7        7.6     Robbins Gioa
  Alexandria, Virginia                                                                             National Certification 
                                                                                                     Commission on Acupuncture
                                                                                                     and Oriental Medicine

99 Canal Center(5)                1986        100%        138,000       99%      18        3.6     Lowe, Price, LeBlanc & Becker
  Alexandria, Virginia                                                                             Howard, Needles, Tannen & 
                                                                                                    Bergendoff
                                                                                                   National District Attorney's 
                                                                                                    Association

TransPotomac Plaza 5(5)           1983        100%         96,000      100%      11        5.7     Cities In Schools
  Alexandria, Virginia                                                                             The Onyx Group
                                                                                                   The Hawthorn Group

Sixty State Street(9)             1979        100%        823,000       99%      36        8.9     Hale & Dorr
  Boston, Massachusetts                                                                            The Pioneer Group, Inc.
                                                                                                   ITT/Sheraton

Corporate 500 Centre(10)       1986/1990      100%        679,000       95%      40        6.0     MMI Companies, Inc.
  Deerfield, Illinois                                                                              Fortune Brands
                                                                                                   Gaylord Container

One Memorial Drive(11)            1987        100%        353,000      100%      13        8.0     Sapient Corporation
  Cambridge, Massachusetts                                                                         InterSystems Corporation
                                                                                                   David L. Babson, Inc.

201 California Street(12)         1980        100%        240,000      100%       8        2.8     Bank of America
  San Francisco, California                                                                        Sutro & Company
                                                                                                   McCann Erickson, Inc.

Wilshire Palisades(12)            1981        100%        186,000      100%      16        4.2     Wilshire Associates, Inc.
  Santa Monica, California                                                                         Paul Hastings Janofsky Walker
                                                                                                   Dimensional Fund Advisors

                                            ---------  -----------  ---------  ------  ----------
                                               85%     11,387,000       98%     668        6.8
                                            ---------  -----------  ---------  ------  ----------
                                            ---------  -----------  ---------  ------  ----------

</TABLE>


<PAGE>


                           Cornerstone Properties Inc.
                               Table of Properties
                                    Footnotes

- ----------

(1)  While the Company's stated interest in the partnership which owns Norwest
     Center is 50%, its economic interest in the Property is significantly
     larger because of priority distributions it receives on its invested
     capital base. For the nine months ended September 30, 1998, the Company's
     share of earnings and cash distributions from the partnership that owns
     Norwest Center was 81.0%.

(2)  While the Company's stated interest in the partnership which owns
     Washington Mutual Tower is 50%, its economic interest in the Property is
     significantly larger because of priority distributions it receives on its
     invested capital base. For the nine months ended September 30, 1998, the
     Company received 100% of the cash distributions from the partnership that
     owns Washington Mutual Tower.

(3)  Includes the Galland and Seneca Buildings.

(4)  The Company's headquarters are located at Tower 56.

(5)  Property acquired in the DIHC Acquisition.

(6)  While the Company's stated interest in the partnership that owns 191
     Peachtree Street is 80%, its economic interest is significantly larger
     since it has acquired the first mortgage note on the Property in the amount
     of $145 million, which earns interest at 9.375%, and will receive a
     priority distribution on its acquired capital base. In 1997, the partner in
     the transaction, CH Associates, Ltd., received an annual incentive
     distribution of $250,000 which the Company expects it will continue to
     receive under the partnership agreement through February 28, 2000, with the
     Company receiving the remainder of the cash flow of the property.

(7)  In January 1998, the Company acquired partnership interests with a stated
     interest of approximately 59% in the partnerships that own Market Square,
     with the option to purchase an additional 1%. The Company's economic
     interest is significantly larger since it has acquired the first mortgage
     note on the Property in the amount of $181 million which earns interest at
     9.75%, and will receive a priority distribution on its acquired capital
     base. In addition, the Company acquired a "buffer loan", with accrued
     principal and interest of $49.0 million at purchase, which accrues interest
     at a rate of 11% per annum and is payable from cash flow, refinancing or
     sales proceeds from Market Square in excess of the first mortgage. During
     the nine months ended September 30, 1998, the Company received 100% of the
     cash flow from the Property. The Company accounts for the transaction as an
     equity investment in real estate.

(8)  Distributions of cash flow and sales and refinancing proceeds are shared in
     proportion to the Company's 91.5% partnership interest and Hines Interests
     Limited Partnership's and/or its affiliates' ("Hines") 8.5% partnership
     interest.

(9)  On December 31, 1997, the Company purchased the second mortgage on Sixty
     State Street. The mortgage is a cash flow mortgage through which all the
     economic benefits/risks (subject to the first mortgage) will inure to the
     Company. The Company controls all major decisions regarding management and
     leasing. The total purchase price for the second mortgage was $131.5
     million.

(10) The Property was acquired by the Company in January 1998.

(11) The Property was acquired by the Company in April 1998.

(12) The Properties were acquired by the Company in June 1998.


<PAGE>


                           Cornerstone Properties Inc.





                           Supplemental Information to

                           Quarterly Earnings Release





                           - Top Ten Tenants Schedule


<PAGE>

                          Cornerstone Properties Inc.
                            Top Ten Tenants Schedule
                            As of September 30, 1998

The Company's tenants include local, regional, national and international
companies engaged in a wide variety of businesses. The following table sets
forth, as of September 30, 1998, information concerning the ten largest tenants
(ranked by Full Service Straight-Line Rent as of that date) occupying the
Properties. "Full Service Straight-Line Rent" is Straight-Line Rent plus annual
operating expense recoveries. "Straight-Line Rent" means the annual average of
all Actual Rent required to be paid through the term of the lease, calculated in
accordance with GAAP. Full Service Straight-Line Rent does not reflect the cost
of any leasing commissions or tenant improvements.

<TABLE>
<CAPTION>

                                                                         Full Service
                                                                       Straight-Line Rent
                                                                     -----------------------
                                     Straight-Line                                  Percent      Scheduled Lease
          Tenant                          Rent         Recoveries       Amount      of Total     Expiration Date
- -----------------------------------  -------------     -----------   ------------   --------   -------------------
<S>                                  <C>               <C>           <C>              <C>      <C>      <C>   
Norwest Corporation (1)(3)           $ 20,822,000      $11,088,000   $ 31,910,000      9%      Mar-99       19,000
                                                                                               Mar-02       13,000
                                                                                               Jul-03      143,000
                                                                                               Oct-04        6,000
                                                                                               Jul-13      402,000
                                                                                               Aug-18      451,000
                                                                                                         ---------
                                                                                                         1,034,000
                                                                                                        
Massachusetts Financial Services(1)     9,853,000        4,585,000     14,438,000      4%      Feb-03      359,000
                                                                                                        
Wachovia Bank(1)                        8,919,000        3,396,000     12,315,000      4%      Dec-08      380,000
                                                                                                        
Hale & Dorr(1)                          7,943,000        3,993,000     11,936,000      4%      Jun-13      296,000
                                                                                                        
King & Spalding(1)                      8,168,000        2,605,000     10,773,000      3%      Mar-06      305,000
                                                                                                        
Deloitte & Touche(1)                    7,259,000        1,651,000      8,910,000      3%      Feb-99       15,000
                                                                                               Oct-99      130,000
                                                                                               Jun-08       85,000
                                                                                                         ---------
                                                                                                           230,000
                                                                                                        
The New England Life(1)                 5,170,000        2,784,000      7,954,000      2%      Sep-08      218,000
                                                                                                        
Perkins Coie(2)                         6,316,000          503,000      6,819,000      2%      Dec-98        2,000
                                                                                               Jul-03        7,000
                                                                                               Jul-04       32,000
                                                                                               Dec-11      199,000
                                                                                                         ---------
                                                                                                           240,000
                                                                                                        
Houghton Mifflin(1)                     3,456,000        3,188,000      6,644,000      2%      Feb-07      247,000
                                                                                                        
First Union(2)                          6,103,000          200,000      6,303,000      2%      Mar-99       23,000
                                                                                               Jun-00       27,000
                                                                                               Aug-00       23,000
                                                                                               Mar-01       23,000
                                                                                               Aug-01       46,000
                                                                                               Feb-02       23,000
                                                                                               Sep-02       22,000
                                                                                               Aug-08       46,000
                                                                                               Mar-09       23,000
                                                                                               Mar-10       47,000
                                                                                               Mar-11       48,000
                                                                                               Apr-14        4,000
                                                                                                         ---------
                                                                                                           355,000
                                     ------------      -----------   ------------
                                     $ 84,009,000      $33,993,000   $118,002,000     35%                3,664,000
                                     ------------      -----------   ------------    ----                ---------
                                     ------------      -----------   ------------    ----                ---------
                   Total Portfolio   $260,510,000      $78,391,000   $338,901,000                     
                                     ------------      -----------   ------------
                                     ------------      -----------   ------------
</TABLE>

<PAGE>

                           Cornerstone Properties Inc.
                            Top Ten Tenants Schedule
                                    Footnotes

- ----------------------------

(1)  Net Lease.

(2)  Gross Lease.

(3)  Norwest Corporation includes Norwest Corporation and Norwest Bank Denver
     N.A.





<PAGE>

                           Cornerstone Properties Inc.



                           Supplemental Information to

                           Quarterly Earnings Release





                         - Historical Occupancy Schedule

<PAGE>

<TABLE>
<CAPTION>

                          Cornerstone Properties Inc.
                         Historical Occupancy Schedule
                            As of September 30, 1998

                            Total Bldg.
                               Sq. Ft.       1994      1995      1996      1997    Q3 1998
                               -------       ----      ----      ----      ----    -------
<S>                         <C>              <C>       <C>       <C>        <C>       <C>
One Norwest Center           1,188,000        96%       98%       99%       99%       97%
Norwest Center               1,118,000       100%      100%      100%       98%       99%
Washington Mutual Tower      1,155,000        97%       97%       97%       97%       99%
125 Summer Street              464,000                  94%      100%       99%       99%
Tower 56                       162,000                  91%       97%       98%       99%
One Lincoln Centre             297,000                            91%       96%       91%
527 Madison Avenue             216,000                            96%      100%      100%
191 Peachtree Street         1,221,000                                      95%       97%
Market Square                  689,000                                      95%       95%
500 Boylston Street            715,000                                     100%      100%
222 Berkeley Street            531,000                                     100%      100%
Charlotte Plaza                613,000                                      94%       98%
200 Galleria                   433,000                                      91%       94%
11 Canal Center                 70,000                                      84%       96%
99 Canal Center                138,000                                      99%       99%
TransPotomac Plaza 5            96,000                                      99%      100%
Sixty State Street             823,000                                      98%       99%
Corporate 500 Centre           679,000                                                95%
One Memorial Drive             353,000                                               100%
201 California Street          240,000                                               100%
Wilshire Palisades             186,000                                               100%
                            ----------       ----      ----      ----      ----      ----
                            11,387,000        98%       98%       97%       97%       98%
                            ----------       ----      ----      ----      ----      ----
                            ----------       ----      ----      ----      ----      ----

</TABLE>


<PAGE>

                           Cornerstone Properties Inc.





                           Supplemental Information to

                           Quarterly Earnings Release





                   - Net Rent and Net Effective Rent Schedule


<PAGE>

                          Cornerstone Properties Inc.
                    Net Rent and Net Effective Rent Schedule
                            As of September 30, 1998

The following tables show the average annual Net Rent and the average annual Net
Effective Rent (each as defined below) per square foot occupied for each of the
Properties for the periods presented during which such Property was owned by the
Company. "Net Rent" as used herein means actual billed rent less Recoveries.
"Net Effective Rent" as used herein means (i) rent determined for each year on a
straight-line basis through the term of the lease, less (ii) Recoveries and the
amortization of deferred leasing costs (tenant improvements, leasing
commissions, and other tenant inducements). Recoveries includes base stops in
gross leases.

Average Annual Net Rent (per square foot occupied)

<TABLE>
<CAPTION>

                           Total Bldg.
                             Sq. Ft.      Q3 1998     1997       1996     1995      1994
                             -------      -------     ----       ----     ----      ----
<S>                        <C>           <C>         <C>       <C>       <C>       <C>    
One Norwest Center          1,188,000    $   12.41   $ 12.46   $ 12.08   $ 11.78   $ 11.61
Norwest Center              1,118,000    $   18.80   $ 18.29   $ 17.94   $ 17.82   $ 17.25
Washington Mutual Tower     1,155,000    $   15.74   $ 15.77   $ 15.98   $ 16.17   $ 15.27
125 Summer Street             464,000    $   22.08   $ 21.27   $ 23.24   $ 22.48   
Tower 56                      162,000    $   22.43   $ 22.76   $ 20.45             
One Lincoln Centre            297,000    $   20.71   $ 19.60   $ 18.56             
527 Madison Avenue            216,000    $   31.64   $ 36.55   $ 35.47             
191 Peachtree Street        1,221,000    $   20.78   $ 21.07                       
Market Square                 689,000    $   26.34                                 
500 Boylston Street           715,000    $   26.04   $ 25.89                       
222 Berkeley Street           531,000    $   16.98   $ 16.68                       
Charlotte Plaza               613,000    $    9.92   $  9.35                       
200 Galleria                  433,000    $   14.39   $ 12.92                       
11 Canal Center                70,000    $   14.96   $ 14.11                       
99 Canal Center               138,000    $   15.00   $ 14.49                       
TransPotomac Plaza 5           96,000    $   11.75   $ 12.55                       
Sixty State Street            823,000    $   19.41                                 
Corporate 500 Centre          679,000    $   21.03                                 
One Memorial Drive            353,000    $   14.59                                 
201 California Street         240,000    $   11.50                                 
Wilshire Palisades            186,000    $   24.54                                 
                           ----------    ---------   -------   -------   -------   -------
Weighted Average           11,387,000    $   18.55   $ 17.46   $ 16.99   $ 16.06   $ 14.65
                           ----------    ---------   -------   -------   -------   -------
                           ----------    ---------   -------   -------   -------   -------

</TABLE>

Average Annual Net Effective Rents (per square foot occupied)

<TABLE>
<CAPTION>

                           Total Bldg.
                             Sq. Ft.      Q3 1998    1997       1996     1995      1994
                           ----------     -------    ----       ----     ----      ----
<S>                        <C>           <C>        <C>       <C>       <C>       <C>    
One Norwest Center          1,188,000    $   11.97   $ 11.66   $ 10.80   $ 10.56   $ 10.25
Norwest Center              1,118,000    $   17.58   $ 17.23   $ 17.43   $ 17.31   $ 17.00
Washington Mutual Tower     1,155,000    $   14.97   $ 12.02   $ 11.80   $ 11.83   $ 11.03
125 Summer Street             464,000    $   19.24   $ 20.00   $ 22.27   $ 23.33   
Tower 56                      162,000    $   22.41   $ 21.56   $ 21.17             
One Lincoln Centre            297,000    $   20.11   $ 19.76   $ 19.70             
527 Madison Avenue            216,000    $   33.11   $ 36.89   $ 30.99             
191 Peachtree Street        1,221,000    $   23.91   $ 24.26                       
Market Square                 689,000    $   28.44                                 
500 Boylston Street           715,000    $   26.34   $ 26.08                       
222 Berkeley Street           531,000    $   18.57   $ 18.08                       
Charlotte Plaza               613,000    $   10.17   $  9.76
200 Galleria                  433,000    $   14.70   $ 13.52                       
11 Canal Center                70,000    $   15.84   $ 14.72
99 Canal Center               138,000    $   15.70   $ 15.00
TransPotomac Plaza 5           96,000    $   12.93   $ 14.29                       
Sixty State Street            823,000    $   23.26                                 
Corporate 500 Centre          679,000    $   22.82                                 
One Memorial Drive            353,000    $   16.71                                 
201 California Street         240,000    $   11.66                                 
Wilshire Palisades            186,000    $   26.21                                 
                           ----------    ---------   -------   -------   -------   -------
Weighted Average           11,387,000    $   19.29   $ 17.28   $ 15.43   $ 14.37   $ 12.69
                           ----------    ---------   -------   -------   -------   -------
                           ----------    ---------   -------   -------   -------   -------

</TABLE>


<PAGE>

                           Cornerstone Properties Inc.



                           Supplemental Information to

                           Quarterly Earnings Release









                           - Lease Expiration Schedule


<PAGE>

Lease Expiration Schedule
The following table sets forth certain categories of information relating to
lease expirations for all of the Properties owned as of September 30, 1998.

<TABLE>
<CAPTION>

                                                                         Q4
PROPERTY                                                                1998           1999          2000            2001       
- --------                                                                ----           ----          ----            ----       
<S>                         <C>                                     <C>            <C>            <C>            <C>          
One Norwest Center (1)      Square feet expiring(3)                    2,283 sf      40,238 sf     124,001 sf      60,785 sf    
                            Straight-Line rent(4)                   $    10,137    $   424,003    $ 1,107,729    $   666,600    
                            Straight-Line rent per sq. ft           $      4.44    $     10.54    $      8.93    $     10.97    
                            Recoveries (5)                          $    13,731    $   249,372    $   762,519    $   377,493    
                            Full service St-Line rent(6)            $    23,868    $   673,375    $ 1,870,248    $ 1,044,093    
                            Full service St-Line rent per sq. ft    $     10.45    $     16.73    $     15.08    $     17.18    
                            % Full service St-Lined rent                   0.11%          3.03%          8.41%          4.70%   
                            Asking market rent per sq. ft.(7)       $     22.00
                            No. of tenant leases expiring(8)                  1              4              7              6

Norwest Center(1)           Square feet expiring                      10,127 sf      23,059 sf     107,510 sf       4,774 sf    
                            Straight-Line rent                      $   124,131    $   351,980    $ 1,701,411    $    82,056    
                            Straight-Line rent per sq. ft           $     12.26    $     15.26    $     15.83    $     17.19    
                            Recoveries                              $   130,879    $   292,793    $ 1,641,282    $    72,396    
                            Full service St-Line rent               $   255,010    $   644,773    $ 3,342,693    $   154,452    
                            Full service St-Line rent per sq. ft    $     25.18    $     27.96    $     31.09    $     32.35    
                            % Full service St-Lined rent                   0.64%          1.63%          8.45%          0.39%   
                            Asking market rent per sq. ft           $     35.00
                            No. of tenant leases expiring                     4              1              4              2    

Washington Mutual Tower(2)  Square feet expiring                      15,791 sf     147,737 sf      52,783 sf      49,280 sf    
                            Straight-Line rent                      $   175,088    $ 2,742,855    $   853,988    $ 1,092,648    
                            Straight-Line rent per sq. ft           $     11.09    $     18.57    $     16.18    $     22.17    
                            Recoveries                              $     2,181    $   116,969    $    37,231    $    35,020    
                            Full service St-Line rent               $   177,269    $ 2,859,824    $   891,219    $ 1,127,668    
                            Full service St-Line rent per sq. ft    $     11.23    $     19.36    $     16.88    $     22.88    
                            % Full service St-Lined rent                   0.68%         11.01%          3.43%          4.34%   
                            Asking market rent per sq. ft           $     34.00
                            No. of tenant leases expiring                     7             20             13             12    


125 Summer Street(2)        Square feet expiring                       2,890 sf     154,124 sf      50,547 sf       3,438 sf    
                            Straight-Line rent                      $    54,220    $ 5,591,172    $ 1,522,302    $    67,698    
                            Straight-Line rent per sq. ft           $     18.76    $     36.28    $     30.12    $     19.69    
                            Recoveries                              $    24,966    $ 1,099,926    $   226,602    $    47,646    
                            Full service St-Line rent               $    79,186    $ 6,691,098    $ 1,748,904    $   115,344    
                            Full service St-Line rent per sq. ft    $     27.40    $     43.41    $     34.60    $     33.55    
                            % Full service St-Lined rent                   0.48%         40.18%         10.50%          0.69%   
                            Asking market rent per sq. ft           $     45.00
                            No. of tenant leases expiring                     3              4              6              1    

Tower 56(2)                 Square feet expiring                       8,175 sf      24,549 sf      17,341 sf      44,188 sf    
                            Straight-Line rent                      $   328,704    $ 1,073,147    $   720,286    $ 1,877,796    
                            Straight-Line rent per sq. ft           $     40.21    $     43.71    $     41.54    $     42.50    
                            Recoveries                              $     7,778    $    14,982    $     4,647    $    18,296    
                            Full service St-Line rent               $   336,482    $ 1,088,129    $   724,933    $ 1,896,092    
                            Full service St-Line rent per sq. ft    $     41.16    $     44.32    $     41.80    $     42.91    
                            % Full service St-Lined rent                   4.72%         15.25%         10.16%         26.57%   
                            Asking market rent per sq. ft           $     56.00
                            No. of tenant leases expiring                     3              6              7             11    

One Lincoln Centre(1)       Square feet expiring                       1,203 sf      68,385 sf      77,684 sf      13,310 sf    
                            Straight-Line rent                      $    21,660    $ 1,204,605    $ 1,440,852    $   245,796    
                            Straight-Line rent per sq. ft           $     18.00    $     17.62    $     18.55    $     18.47    
                            Recoveries                              $    11,028    $   628,896    $   653,796    $   123,996    
                            Full service St-Line rent               $    32,688    $ 1,833,501    $ 2,094,648    $   369,792    
                            Full service St-Line rent per sq. ft    $     27.17    $     26.81    $     26.96    $     27.78    
                            % Full service St-Lined rent                   0.43%         24.14%         27.58%          4.87%   
                            Asking market rent per sq. ft           $     28.00
                            No. of tenant leases expiring                     1              9             12              4    

527 Madison Avenue(2)       Square feet expiring                      12,254 sf       2,114 sf       9,195 sf      78,444 sf    
                            Straight-Line rent                      $   647,182    $   107,814    $   380,248    $ 4,510,527    
                            Straight-Line rent per sq. ft           $     52.81    $     51.00    $     41.35    $     57.50    
                            Recoveries                              $    81,288    $     9,455    $      --      $   473,256    
                            Full service St-Line rent               $   728,470    $   117,269    $   380,248    $ 4,983,783    
                            Full service St-Line rent per sq. ft    $     59.45    $     55.47    $     41.35    $     63.53    
                            % Full service St-Lined rent                   6.02%          0.97%          3.14%         41.16%   
                            Asking market rent per sq. ft           $     56.00
                            No. of tenant leases expiring                     3              1              2              1    

</TABLE>

<PAGE>

<TABLE>
<CAPTION>
         
         
PROPERTY                                                               2002           2003           2004            2005    
- --------                                                               ----           ----           ----            ----    
<S>                         <C>                                     <C>            <C>            <C>                       
One Norwest Center (1)      Square feet expiring(3)                  135,086 sf     182,284 sf     125,173 sf                
                            Straight-Line rent(4)                   $ 1,265,803    $ 2,417,990    $ 1,569,248                
                            Straight-Line rent per sq. ft           $      9.37    $     13.26    $     12.54                
                            Recoveries (5)                          $   832,455    $ 1,144,607    $   779,817                
                            Full service St-Line rent(6)            $ 2,098,258    $ 3,562,597    $ 2,349,065                
                            Full service St-Line rent per sq. ft    $     15.53    $     19.54    $     18.77                
                            % Full service St-Lined rent                   9.44%         16.03%         10.57%               
                            Asking market rent per sq. ft.(7)                                                                
                            No. of tenant leases expiring(8)                 15              7              3                
                                                                                                                             
Norwest Center(1)           Square feet expiring                      53,390 sf     184,361 sf     170,787 sf      18,881 sf 
                            Straight-Line rent                      $   454,717    $ 2,845,245    $ 3,064,584    $   359,296 
                            Straight-Line rent per sq. ft           $      8.52    $     15.43    $     17.94    $     19.03 
                            Recoveries                              $   783,781    $ 2,850,537    $ 2,438,357    $   295,489 
                            Full service St-Line rent               $ 1,238,498    $ 5,695,782    $ 5,502,941    $   654,785 
                            Full service St-Line rent per sq. ft    $     23.20    $     30.89    $     32.22    $     34.68 
                            % Full service St-Lined rent                   3.13%         14.39%         13.91%          1.65%
                            Asking market rent per sq. ft                                                                    
                            No. of tenant leases expiring                     4              4              9              1 
                                                                                                                             
Washington Mutual Tower(2)  Square feet expiring                     120,126 sf     269,418 sf     129,374 sf      14,354 sf 
                            Straight-Line rent                      $ 2,699,685    $ 5,545,817    $ 2,871,435    $   275,117 
                            Straight-Line rent per sq. ft           $     22.47    $     20.58    $     22.19    $     19.17 
                            Recoveries                              $    29,031    $   271,173    $   103,724    $     5,393 
                            Full service St-Line rent               $ 2,728,716    $ 5,816,990    $ 2,975,159    $   280,510 
                            Full service St-Line rent per sq. ft    $     22.72    $     21.59    $     23.00    $     19.54 
                            % Full service St-Lined rent                  10.51%         22.40%         11.46%          1.08%
                            Asking market rent per sq. ft                                                                    
                            No. of tenant leases expiring                     9             17              6              2 
                                                                                                                             
                                                                                                                             
125 Summer Street(2)        Square feet expiring                     127,853 sf      27,311 sf                      9,503 sf 
                            Straight-Line rent                      $ 1,722,513    $   583,747                   $   274,478 
                            Straight-Line rent per sq. ft           $     13.47    $     21.37                   $     28.88 
                            Recoveries                              $ 1,789,536    $   305,712                   $    16,601 
                            Full service St-Line rent               $ 3,512,049    $   889,459                   $   291,079 
                            Full service St-Line rent per sq. ft    $     27.47    $     32.57                   $     30.63 
                            % Full service St-Lined rent                  21.09%          5.34%                         1.75%
                            Asking market rent per sq. ft                                                                    
                            No. of tenant leases expiring                     5              5                             1 
                                                                                                                             
Tower 56(2)                 Square feet expiring                      33,231 sf      15,000 sf      18,459 sf                
                            Straight-Line rent                      $ 1,615,384    $   704,832    $   733,632                
                            Straight-Line rent per sq. ft           $     48.61    $     46.99    $     39.74                
                            Recoveries                              $    12,046    $    10,527    $    13,315                
                            Full service St-Line rent               $ 1,627,430    $   715,359    $   746,947                
                            Full service St-Line rent per sq. ft    $     48.97    $     47.69    $     40.47                
                            % Full service St-Lined rent                  22.81%         10.03%         10.47%               
                            Asking market rent per sq. ft                                                                    
                            No. of tenant leases expiring                     9              4              4                
                                                                                                                             
One Lincoln Centre(1)       Square feet expiring                      80,668 sf      27,894 sf                               
                            Straight-Line rent                      $ 1,750,992    $   453,511                               
                            Straight-Line rent per sq. ft           $     21.71    $     16.26                               
                            Recoveries                              $   740,580    $   319,668                               
                            Full service St-Line rent               $ 2,491,572    $   773,179                               
                            Full service St-Line rent per sq. ft    $     30.89    $     27.72                               
                            % Full service St-Lined rent                  32.80%         10.18%                              
                            Asking market rent per sq. ft                                                                    
                            No. of tenant leases expiring                     7              8                               
                                                                                                                             

527 Madison Avenue(2)       Square feet expiring                       3,533 sf      35,590 sf      7,937 sf*       5,823 sf 
                            Straight-Line rent                      $   180,180    $ 1,514,359    $ 1,140,060    $   276,732 
                            Straight-Line rent per sq. ft           $     51.00    $     42.55    $    143.64    $     47.52 
                            Recoveries                              $      --      $    45,187    $     6,506    $      --   
                            Full service St-Line rent               $   180,180    $ 1,559,546    $ 1,146,566    $   276,732 
                            Full service St-Line rent per sq. ft    $     51.00    $     43.82    $    144.46    $     47.52 
                            % Full service St-Lined rent                   1.49%         12.88%          9.47%          2.29%
                            Asking market rent per sq. ft                                                                    
                            No. of tenant leases expiring                     1              4              1              1 

</TABLE>

<PAGE>

<TABLE>  
<CAPTION>
         
                                                                                                      2008 and                  
PROPERTY                                                                 2006           2007           Beyond        Total      
- --------                                                                 ----           ----           ------        -----      
<S>                         <C>                                                      <C>           <C>             <C>          
One Norwest Center (1)      Square feet expiring(3)                                    76,470 sf     407,151 sf    1,153,471 sf 
                            Straight-Line rent(4)                                    $ 1,119,452    $ 6,431,062    $15,012,024  
                            Straight-Line rent per sq. ft                            $     14.64    $     15.80    $     13.01  
                            Recoveries (5)                                           $   478,496    $ 2,578,701    $ 7,217,191  
                            Full service St-Line rent(6)                             $ 1,597,948    $ 9,009,763    $22,229,215  
                            Full service St-Line rent per sq. ft                     $     20.90    $     22.13    $     19.27  
                            % Full service St-Lined rent                                    7.19%         40.53%        100.00% 
                            Asking market rent per sq. ft.(7)                                                                   
                            No. of tenant leases expiring(8)                                   2              2             47  
                                                                                                                                
Norwest Center(1)           Square feet expiring                                                     538,573 sf    1,111,462 sf 
                            Straight-Line rent                                                      $13,737,867    $22,721,287  
                            Straight-Line rent per sq. ft                                           $     25.51    $     20.44  
                            Recoveries                                                              $ 8,347,070    $16,852,584  
                            Full service St-Line rent                                               $22,084,937    $39,573,871  
                            Full service St-Line rent per sq. ft                                    $     41.01    $     35.61  
                            % Full service St-Lined rent                                                  55.81%        100.00% 
                            Asking market rent per sq. ft                                                                       
                            No. of tenant leases expiring                                                     2             31  
                                                                                                                                
Washington Mutual Tower(2)  Square feet expiring                         4,070 sf     137,888 sf     199,110 sf    1,139,931 sf 
                            Straight-Line rent                         $   97,680    $ 2,652,965    $ 5,605,002    $24,612,280  
                            Straight-Line rent per sq. ft              $    24.00    $     19.24    $     28.15    $     21.59  
                            Recoveries                                 $     --      $   275,716    $   482,478    $ 1,358,916  
                            Full service St-Line rent                  $   97,680    $ 2,928,681    $ 6,087,480    $25,971,196  
                            Full service St-Line rent per sq. ft       $    24.00    $     21.24    $     30.57    $     22.78  
                            % Full service St-Lined rent                     0.38%         11.28%         23.44%        100.00% 
                            Asking market rent per sq. ft                                                                       
                            No. of tenant leases expiring                       1              1              1             89  
                                                                                                                                
                                                                                                                                
125 Summer Street(2)        Square feet expiring                                                      85,169 sf     460,835 sf  
                            Straight-Line rent                                                      $ 2,114,948    $11,931,078  
                            Straight-Line rent per sq. ft                                           $     24.83    $     25.89  
                            Recoveries                                                              $ 1,211,691    $ 4,722,680  
                            Full service St-Line rent                                               $ 3,326,639    $16,653,758  
                            Full service St-Line rent per sq. ft                                    $     39.06    $     36.14  
                            % Full service St-Lined rent                                                  19.98%        100.00% 
                            Asking market rent per sq. ft                                                                       
                            No. of tenant leases expiring                                                     1             26  
                                                                                                                                
Tower 56(2)                 Square feet expiring                                                                    160,943 sf  
                            Straight-Line rent                                                                     $ 7,053,781  
                            Straight-Line rent per sq. ft                                                          $     43.83  
                            Recoveries                                                                             $    81,591  
                            Full service St-Line rent                                                              $ 7,135,372  
                            Full service St-Line rent per sq. ft                                                   $     44.33  
                            % Full service St-Lined rent                                                                100.00% 
                            Asking market rent per sq. ft                                                                       
                            No. of tenant leases expiring                                                                   44  
                                                                                                                                
One Lincoln Centre(1)       Square feet expiring                                                                    269,144 sf  
                            Straight-Line rent                                                                     $ 5,117,416  
                            Straight-Line rent per sq. ft                                                          $     19.01  
                            Recoveries                                                                             $ 2,477,964  
                            Full service St-Line rent                                                              $ 7,595,380  
                            Full service St-Line rent per sq. ft                                                   $     28.22  
                            % Full service St-Lined rent                                                                100.00% 
                            Asking market rent per sq. ft                                                                       
                            No. of tenant leases expiring                                                                   41  
                                                                                                                                
527 Madison Avenue(2)       Square feet expiring                        27,074 sf      32,929 sf                    214,893 sf  
                            Straight-Line rent                         $1,119,356    $ 1,612,968                   $11,489,426  
                            Straight-Line rent per sq. ft              $    41.34    $     48.98                   $     53.47  
                            Recoveries                                 $      609    $     3,805                   $   620,106  
                            Full service St-Line rent                  $1,119,965    $ 1,616,773                   $12,109,532  
                            Full service St-Line rent per sq. ft       $    41.37    $     49.10                   $     56.35  
                            % Full service St-Lined rent                     9.25%         13.35%                       100.00% 
                            Asking market rent per sq. ft                                                                       
                            No. of tenant leases expiring                       4              2                            20  
</TABLE>

<PAGE>


<TABLE>
<CAPTION>

                                                                         Q4
PROPERTY                                                                1998           1999          2000            2001       
- --------                                                                ----           ----          ----            ----       
<S>                         <C>                                     <C>            <C>            <C>            <C>          
191 Peachtree Street(1)     Square feet expiring                       4,372 sf       1,501 sf       6,347 sf     146,035 sf    
                            Straight-Line rent                      $      --      $    22,515    $    68,399    $ 2,809,015    
                            Straight-Line rent per sq. ft           $      --      $     15.00    $     10.78    $     19.24    
                            Recoveries                                             $    10,248    $    61,456    $ 1,278,452    
                            Full service St-Line rent               $      --      $    32,763    $   129,855    $ 4,087,467    
                            Full service St-Line rent per sq. ft    $      --      $     21.83    $     20.46    $     27.99    
                            % Full service St-Lined rent                   0.00%          0.09%          0.34%         10.85%   
                            Asking market rent per sq. ft           $     26.00                                                 
                            No. of tenant leases expiring                     1              1              4              7    

Market Square(2)            Square feet expiring                      32,408 sf       6,544 sf      49,774 sf      90,769 sf    
                            Straight-Line rent                      $ 1,064,508    $   158,328    $ 1,413,552    $ 3,491,160    
                            Straight-Line rent per sq. ft           $     32.85    $     24.19    $     28.40    $     38.46    
                            Recoveries                                             $    17,496    $   344,508    $   548,160    
                            Full service St-Line rent               $ 1,064,508    $   175,824    $ 1,758,060    $ 4,039,320    
                            Full service St-Line rent per sq. ft    $     32.85    $     26.87    $     35.32    $     44.50    
                            % Full service St-Lined rent                   3.89%          0.64%          6.42%         14.76%   
                            Asking market rent per sq. ft           $     46.00
                            No. of tenant leases expiring                     2              2              7              8    

500 Boylston Street(1)      Square feet expiring                                     15,641 sf                        673 sf    
                            Straight-Line rent                                     $   300,225                   $    10,095    
                            Straight-Line rent per sq. ft                          $     19.19                   $     15.00    
                            Recoveries                                             $    92,547                   $     5,841    
                            Full service St-Line rent                              $   392,772                   $    15,936    
                            Full service St-Line rent per sq. ft                   $     25.11                   $     23.68    
                            % Full service St-Lined rent                                  1.58%                         0.06%   
                            Asking market rent per sq. ft           $     47.00
                            No. of tenant leases expiring                                    3                             1    

222 Berkeley Street(1)      Square feet expiring                                     35,923 sf       2,926 sf      84,319 sf    
                            Straight-Line rent                                     $   582,047    $   157,240    $ 2,305,800    
                            Straight-Line rent per sq. ft                          $     16.20    $     53.74    $     27.35    
                            Recoveries                                             $   458,083    $    31,203    $   957,870    
                            Full service St-Line rent                              $ 1,040,130    $   188,443    $ 3,263,670    
                            Full service St-Line rent per sq. ft                   $     28.95    $     64.40    $     38.71    
                            % Full service St-Lined rent                                  6.17%          1.12%         19.35%   
                            Asking market rent per sq. ft           $     47.00                                                 
                            No. of tenant leases expiring                                    3              1              9    

Charlotte Plaza(2)          Square feet expiring                       4,953 sf      33,101 sf      53,325 sf      70,116 sf    
                            Straight-Line rent                      $    48,996    $   626,088    $   939,084    $ 1,186,536    
                            Straight-Line rent per sq. ft           $      9.89    $     18.91    $     17.61    $     16.92    
                            Recoveries                              $       696    $    18,048    $    21,492    $    24,864    
                            Full service St-Line rent               $    49,692    $   644,136    $   960,576    $ 1,211,400    
                            Full service St-Line rent per sq. ft    $     10.03    $     19.46    $     18.01    $     17.28    
                            % Full service St-Lined rent                   0.48%          6.19%          9.24%         11.65%   
                            Asking market rent per sq. ft           $     24.00
                            No. of tenant leases expiring                     2              6              4              2    

200 Galleria(2)             Square feet expiring                       4,922 sf      23,963 sf      70,119 sf      55,400 sf    
                            Straight-Line rent                      $   101,352    $   487,620    $ 1,612,020    $ 1,149,948    
                            Straight-Line rent per sq. ft           $     20.59    $     20.35    $     22.99    $     20.76    
                            Recoveries                              $      --      $    16,896    $    53,808    $    33,492    
                            Full service St-Line rent               $   101,352    $   504,516    $ 1,665,828    $ 1,183,440    
                            Full service St-Line rent per sq. ft    $     20.59    $     21.05    $     23.76    $     21.36    
                            % Full service St-Lined rent                   1.10%          5.48%         18.08%         12.85%   
                            Asking market rent per sq. ft           $     27.00
                            No. of tenant leases expiring                     2              4             16             12    

11 Canal Center(2)          Square feet expiring                                      2,944 sf       2,033 sf       1,572 sf    
                            Straight-Line rent                                     $    66,936    $    39,852    $    37,308    
                            Straight-Line rent per sq. ft                          $     22.74    $     19.60    $     23.73    
                            Recoveries                                             $      --      $     1,272    $      --      
                            Full service St-Line rent                              $    66,936    $    41,124    $    37,308    
                            Full service St-Line rent per sq. ft                   $     22.74    $     20.23    $     23.73    
                            % Full service St-Lined rent                                  4.02%          2.47%          2.24%   
                            Asking market rent per sq. ft           $     27.00                                                 
                            No. of tenant leases expiring                                    1              1              1    


</TABLE>

<TABLE>
<CAPTION>
         
         
PROPERTY                                                               2002           2003           2004            2005    
- --------                                                               ----           ----           ----            ----    
<S>                         <C>                                     <C>            <C>            <C>            <C>
191 Peachtree Street(1)     Square feet expiring                      28,571 sf       6,535 sf      34,394 sf      21,508 sf    
                            Straight-Line rent                      $   472,152    $   107,199    $   748,236    $   370,947    
                            Straight-Line rent per sq. ft           $     16.53    $     16.40    $     21.75    $     17.25    
                            Recoveries                              $   226,766    $    39,334    $   232,468    $   142,810    
                            Full service St-Line rent               $   698,928    $   146,533    $   980,704    $   513,757    
                            Full service St-Line rent per sq. ft    $     24.46    $     22.42    $     28.51    $     23.89    
                            % Full service St-Lined rent                   1.85%          0.39%          2.60%          1.36%   
                            Asking market rent per sq. ft                                                                       
                            No. of tenant leases expiring                     4              2              3              5    
                                                                                                                                
Market Square(2)            Square feet expiring                       6,658 sf      16,870 sf      32,835 sf     173,827 sf    
                            Straight-Line rent                      $   201,792    $   626,076    $ 1,183,692    $ 5,822,184    
                            Straight-Line rent per sq. ft           $     30.31    $     37.11    $     36.05    $     33.49    
                            Recoveries                              $    13,548    $   102,876    $   185,996    $ 1,881,432    
                            Full service St-Line rent               $   215,340    $   728,952    $ 1,369,688    $ 7,703,616    
                            Full service St-Line rent per sq. ft    $     32.34    $     43.21    $     41.71    $     44.32    
                            % Full service St-Lined rent                   0.79%          2.66%          5.00%         28.14%   
                            Asking market rent per sq. ft                                                                       
                            No. of tenant leases expiring                     3              4              4              4    
                                                                                                                                
500 Boylston Street(1)      Square feet expiring                                    459,999 sf      16,079 sf                   
                            Straight-Line rent                                     $10,687,502    $   307,592                   
                            Straight-Line rent per sq. ft                          $     23.23    $     19.13                   
                            Recoveries                                             $ 4,946,406    $   202,622                   
                            Full service St-Line rent                              $15,633,908    $   510,214                   
                            Full service St-Line rent per sq. ft                   $     33.99    $     31.73                   
                            % Full service St-Lined rent                                 62.88%          2.05%                  
                            Asking market rent per sq. ft                                                                       
                            No. of tenant leases expiring                                    4              3                   
                                                                                                                                
222 Berkeley Street(1)      Square feet expiring                      93,829 sf                                                 
                            Straight-Line rent                      $ 1,830,139                                                 
                            Straight-Line rent per sq. ft           $     19.51                                                 
                            Recoveries                              $ 1,190,070                                                 
                            Full service St-Line rent               $ 3,020,209                                                 
                            Full service St-Line rent per sq. ft    $     32.19                                                 
                            % Full service St-Lined rent                  17.91%                                                
                            Asking market rent per sq. ft                                                                       
                            No. of tenant leases expiring                     6                                                 
                                                                                                                                
Charlotte Plaza(2)          Square feet expiring                      73,778 sf      36,995 sf     111,398 sf      17,787 sf    
                            Straight-Line rent                      $ 1,345,956    $   689,220    $ 1,602,420    $   318,456    
                            Straight-Line rent per sq. ft           $     18.24    $     18.63    $     14.38    $     17.90    
                            Recoveries                              $    24,852    $    11,424    $    23,304    $      --      
                            Full service St-Line rent               $ 1,370,808    $   700,644    $ 1,625,724    $   318,456    
                            Full service St-Line rent per sq. ft    $     18.58    $     18.94    $     14.59    $     17.90    
                            % Full service St-Lined rent                  13.18%          6.74%         15.63%          3.06%   
                            Asking market rent per sq. ft                                                                       
                            No. of tenant leases expiring                     9              6              3              2    
                                                                                                                                
200 Galleria(2)             Square feet expiring                     157,022 sf      78,440 sf       3,470 sf                   
                            Straight-Line rent                      $ 3,320,484    $ 1,902,180    $    75,408                   
                            Straight-Line rent per sq. ft           $     21.15    $     24.25    $     21.73                   
                            Recoveries                              $   175,140    $     9,084    $      --                     
                            Full service St-Line rent               $ 3,495,624    $ 1,911,264    $    75,408                   
                            Full service St-Line rent per sq. ft    $     22.26    $     24.37    $     21.73                   
                            % Full service St-Lined rent                  37.95%         20.75%          0.82%                  
                            Asking market rent per sq. ft                                                                       
                            No. of tenant leases expiring                     9             11              1                   
                                                                                                                                
11 Canal Center(2)          Square feet expiring                       5,033 sf                                    13,618 sf    
                            Straight-Line rent                      $   119,784                                  $   358,260    
                            Straight-Line rent per sq. ft           $     23.80                                  $     26.31    
                            Recoveries                              $      --                                    $       432    
                            Full service St-Line rent               $   119,784                                  $   358,692    
                            Full service St-Line rent per sq. ft    $     23.80                                  $     26.34    
                            % Full service St-Lined rent                   7.19%                                       21.53%   
                            Asking market rent per sq. ft                                                                       
                            No. of tenant leases expiring                     1                                            2    

</TABLE>


<TABLE>  
<CAPTION>
         
                                                                                                      2008 and                  
PROPERTY                                                                 2006           2007           Beyond        Total      
- --------                                                                 ----           ----           ------        -----      
<S>                         <C>                                     <C>           <C>            <C>            <C>         

191 Peachtree Street(1)     Square feet expiring                     440,697 sf                   495,739 sf    1,185,699 sf   
                            Straight-Line rent                      $12,093,286                  $11,179,365    $27,871,114    
                            Straight-Line rent per sq. ft           $     27.44                  $     22.55    $     23.51    
                            Recoveries                              $ 3,752,354                  $ 4,071,877    $ 9,815,775    
                            Full service St-Line rent               $15,845,640                  $15,251,242    $37,686,889    
                            Full service St-Line rent per sq. ft    $     35.96                  $     30.76    $     31.78    
                            % Full service St-Lined rent                  42.05%                       40.47%        100.00%   
                            Asking market rent per sq. ft                                                       
                            No. of tenant leases expiring                     3                            4             34    
                                                                                                                               
Market Square(2)            Square feet expiring                      57,781 sf     10,024 sf     171,006 sf     648,496 sf    
                            Straight-Line rent                      $ 2,016,504   $   358,500    $ 5,431,284    $21,767,580    
                            Straight-Line rent per sq. ft           $     34.90   $     35.76    $     31.76    $     33.57    
                            Recoveries                              $   820,586   $     9,247    $ 1,680,384    $ 5,604,233    
                            Full service St-Line rent               $ 2,837,090   $   367,747    $ 7,111,668    $27,371,813    
                            Full service St-Line rent per sq. ft    $     49.10   $     36.69    $     41.59    $     42.21    
                            % Full service St-Lined rent                  10.37%         1.34%         25.98%        100.00%   
                            Asking market rent per sq. ft                                                                      
                            No. of tenant leases expiring                     2             3              8             47    
                                                                                                                               
500 Boylston Street(1)      Square feet expiring                                     3,005 sf     218,826 sf     714,223 sf    
                            Straight-Line rent                                    $    97,663    $ 5,409,488    $16,812,565    
                            Straight-Line rent per sq. ft                         $     32.50    $     24.72    $     23.54    
                            Recoveries                                            $    27,660    $ 2,773,472    $ 8,048,548    
                            Full service St-Line rent                             $   125,323    $ 8,182,960    $24,861,113    
                            Full service St-Line rent per sq. ft                  $     41.70    $     37.39    $     34.81    
                            % Full service St-Lined rent                                 0.50%         32.91%        100.00%   
                            Asking market rent per sq. ft                                                                      
                            No. of tenant leases expiring                                   1              2             14    
                                                                                                                               
222 Berkeley Street(1)      Square feet expiring                                   274,583 sf      39,068 sf     530,648 sf    
                            Straight-Line rent                                    $ 4,232,992    $ 1,064,911    $10,173,129    
                            Straight-Line rent per sq. ft                         $     15.42    $     27.26    $     19.17    
                            Recoveries                                            $ 3,537,317    $   515,964    $ 6,690,507    
                            Full service St-Line rent                             $ 7,770,309    $ 1,580,875    $16,863,636    
                            Full service St-Line rent per sq. ft                  $     28.30    $     40.46    $     31.78    
                            % Full service St-Lined rent                                46.08%          9.37%        100.00%   
                            Asking market rent per sq. ft                                                      
                            No. of tenant leases expiring                                   6              3             28    
                                                                                                                               
Charlotte Plaza(2)          Square feet expiring                      1,222 sf       9,889 sf     189,008 sf     601,572 sf    
                            Straight-Line rent                      $   23,652    $   217,560    $ 3,128,952    $10,126,920    
                            Straight-Line rent per sq. ft           $    19.36    $     22.00    $     16.55    $     16.83    
                            Recoveries                              $     --      $      --      $   147,624    $   272,304    
                            Full service St-Line rent               $   23,652    $   217,560    $ 3,276,576    $10,399,224    
                            Full service St-Line rent per sq. ft    $    19.36    $     22.00    $     17.34    $     17.29    
                            % Full service St-Lined rent                  0.23%          2.09%         31.51%        100.00%   
                            Asking market rent per sq. ft                                                                      
                            No. of tenant leases expiring                    1              1              6             42    
                                                                                                                               
200 Galleria(2)             Square feet expiring                     11,384 sf                                   404,720 sf    
                            Straight-Line rent                      $  262,068                                  $ 8,911,080    
                            Straight-Line rent per sq. ft           $    23.02                                  $     22.02    
                            Recoveries                              $   12,756                                  $   301,176    
                            Full service St-Line rent               $  274,824                                  $ 9,212,256    
                            Full service St-Line rent per sq. ft    $    24.14                                  $     22.76    
                            % Full service St-Lined rent                  2.98%                                      100.00%   
                            Asking market rent per sq. ft                                                                      
                            No. of tenant leases expiring                    1                                           56    
                                                                                                                               
11 Canal Center(2)          Square feet expiring                                    41,967 sf                     67,167 sf    
                            Straight-Line rent                                    $ 1,041,780                   $ 1,663,920    
                            Straight-Line rent per sq. ft                         $     24.82                   $     24.77    
                            Recoveries                                            $      --                     $     1,704    
                            Full service St-Line rent                             $ 1,041,780                   $ 1,665,624    
                            Full service St-Line rent per sq. ft                  $     24.82                   $     24.80    
                            % Full service St-Lined rent                                62.55%                       100.00%   
                            Asking market rent per sq. ft                                                    
                            No. of tenant leases expiring                                   1                             7    

</TABLE>

<PAGE>


<TABLE>
<CAPTION>

                                                                         Q4
PROPERTY                                                                1998           1999          2000            2001       
- --------                                                                ----           ----          ----            ----       
<S>                         <C>                                     <C>            <C>            <C>            <C>          

99 Canal Center(2)          Square feet expiring                       1,647 sf       4,693 sf       9,063 sf      51,666 sf    
                            Straight-Line rent                      $      --      $    76,092    $   209,136    $ 1,253,160    
                            Straight-Line rent per sq. ft           $      --      $     16.21    $     23.08    $     24.26    
                            Recoveries                              $      --      $     6,132    $     3,432    $    71,880    
                            Full service St-Line rent               $      --      $    82,224    $   212,568    $ 1,325,040    
                            Full service St-Line rent per sq. ft    $      --      $     17.52    $     23.45    $     25.65    
                            % Full service St-Lined rent                   0.00%          2.48%          6.42%         39.99%   
                            Asking market rent per sq. ft           $     27.00
                            No. of tenant leases expiring                     1              2              2              5    

TransPotomac Plaza 5(2)     Square feet expiring                       3,496 sf       2,081 sf       1,686 sf      14,811 sf    
                            Straight-Line rent                      $    73,416    $    42,732    $    32,640    $   275,316    
                            Straight-Line rent per sq. ft           $     21.00    $     20.53    $     19.36    $     18.59    
                            Recoveries                              $      --      $       984    $       312    $     2,136    
                            Full service St-Line rent               $    73,416    $    43,716    $    32,952    $   277,452    
                            Full service St-Line rent per sq. ft    $     21.00    $     21.01    $     19.54    $     18.73    
                            % Full service St-Lined rent                   3.66%          2.18%          1.64%         13.84%   
                            Asking market rent per sq. ft           $     25.00
                            No. of tenant leases expiring                     1              1              1              1    

Sixty State Street(2)       Square feet expiring                       1,262 sf      33,692 sf       2,762 sf      28,735 sf    
                            Straight-Line rent                      $    38,627    $   697,889    $    74,436    $   871,567    
                            Straight-Line rent per sq. ft           $     30.61    $     20.71    $     26.95    $     30.33    
                            Recoveries                              $     3,753    $   102,419    $     6,537    $    51,125    
                            Full service St-Line rent               $    42,380    $   800,308    $    80,973    $   922,692    
                            Full service St-Line rent per sq. ft    $     33.58    $     23.75    $     29.32    $     32.11    
                            % Full service St-Lined rent                   0.15%          2.85%          0.29%          3.29%   
                            Asking market rent per sq. ft           $     48.00
                            No. of tenant leases expiring                     2              4              1              3    

Corporate 500 Centre(1)     Square feet expiring                       9,893 sf      12,022 sf      36,362 sf      40,723 sf    
                            Straight-Line rent                      $   176,933    $   175,044    $   798,340    $ 1,060,416    
                            Straight-Line rent per sq. ft           $     17.88    $     14.56    $     21.96    $     26.04    
                            Recoveries                              $    38,231    $    63,048    $   343,872    $   376,896    
                            Full service St-Line rent               $   215,164    $   238,092    $ 1,142,212    $ 1,437,312    
                            Full service St-Line rent per sq. ft    $     21.75    $     19.80    $     31.41    $     35.29    
                            % Full service St-Lined rent                   1.12%          1.24%          5.96%          7.50%   
                            Asking market rent per sq. ft           $     29.00
                            No. of tenant leases expiring                     4              4              5              4    

One Memorial Drive(2)       Square feet expiring                       7,874 sf      21,422 sf                                  
                            Straight-Line rent                      $   281,495    $   407,018                                  
                            Straight-Line rent per sq. ft           $     35.75    $     19.00                                  
                            Recoveries                              $    33,480    $    31,829                                  
                            Full service St-Line rent               $   314,975    $   438,847                                  
                            Full service St-Line rent per sq. ft    $     40.00    $     20.49                                  
                            % Full service St-Lined rent                   2.55%          3.56%                                 
                            Asking market rent per sq. ft           $     42.00
                            No. of tenant leases expiring                     1              1                                  

201 California Street(2)    Square feet expiring                                    117,005 sf                     42,778 sf    
                            Straight-Line rent                                     $ 2,623,176                   $   929,136    
                            Straight-Line rent per sq. ft                          $     22.42                   $     21.72    
                            Recoveries                                             $   398,304                   $    31,500    
                            Full service St-Line rent                              $ 3,021,480                   $   960,636    
                            Full service St-Line rent per sq. ft                   $     25.82                   $     22.46    
                            % Full service St-Lined rent                                 47.37%                        15.06%   
                            Asking market rent per sq. ft           $     45.00                                                 
                            No. of tenant leases expiring                                    4                             1    

Wilshire Palisades(2)       Square feet expiring                       1,316 sf                      5,118 sf      71,448 sf    
                            Straight-Line rent                      $    31,584                   $   110,556    $ 3,762,684    
                            Straight-Line rent per sq. ft           $     24.00                   $     21.60    $     52.66    
                            Recoveries                              $     1,380                   $    11,952    $   326,616    
                            Full service St-Line rent               $    32,964                   $   122,508    $ 4,089,300    
                            Full service St-Line rent per sq. ft    $     25.05                   $     23.94    $     57.23    
                            % Full service St-Lined rent                   0.40%                         1.48%         49.25%   
                            Asking market rent per sq. ft           $     42.00
                            No. of tenant leases expiring                     1                             1              6    

</TABLE>
<PAGE>

<TABLE>
<CAPTION>
         
         
PROPERTY                                                               2002           2003           2004            2005    
- --------                                                               ----           ----           ----            ----    
<S>                         <C>                                     <C>            <C>            <C>                       
99 Canal Center(2)          Square feet expiring                      21,710 sf      46,442 sf                                  
                            Straight-Line rent                      $   543,900    $ 1,068,096                                  
                            Straight-Line rent per sq. ft           $     25.05    $     23.00                                  
                            Recoveries                              $    17,772    $    19,320                                  
                            Full service St-Line rent               $   561,672    $ 1,087,416                                  
                            Full service St-Line rent per sq. ft    $     25.87    $     23.41                                  
                            % Full service St-Lined rent                  16.95%         32.82%                                 
                            Asking market rent per sq. ft                                                                       
                            No. of tenant leases expiring                     2              5                                  
                                                                                                                                
TransPotomac Plaza 5(2)     Square feet expiring                      25,926 sf                      7,702 sf                   
                            Straight-Line rent                      $   517,800                   $   177,816                   
                            Straight-Line rent per sq. ft           $     19.97                   $     23.09                   
                            Recoveries                              $     7,764                   $      --                     
                            Full service St-Line rent               $   525,564                   $   177,816                   
                            Full service St-Line rent per sq. ft    $     20.27                   $     23.09                   
                            % Full service St-Lined rent                  26.22%                         8.87%                  
                            Asking market rent per sq. ft                                                                       
                            No. of tenant leases expiring                     2                             2                   
                                                                                                                                
Sixty State Street(2)       Square feet expiring                     189,493 sf      47,354 sf     113,670 sf                   
                            Straight-Line rent                      $ 3,893,189    $ 1,173,338    $ 3,539,587                   
                            Straight-Line rent per sq. ft           $     20.55    $     24.78    $     31.14                   
                            Recoveries                              $ 2,057,400    $    79,341    $   220,607                   
                            Full service St-Line rent               $ 5,950,589    $ 1,252,679    $ 3,760,194                   
                            Full service St-Line rent per sq. ft    $     31.40    $     26.45    $     33.08                   
                            % Full service St-Lined rent                  21.20%          4.46%         13.40%                  
                            Asking market rent per sq. ft                                                                       
                            No. of tenant leases expiring                     5              2             10                   
                                                                                                                                
Corporate 500 Centre(1)     Square feet expiring                      55,101 sf     160,472 sf      13,852 sf                   
                            Straight-Line rent                      $ 1,137,468    $ 3,567,213    $   275,112                   
                            Straight-Line rent per sq. ft           $     20.64    $     22.23    $     19.86                   
                            Recoveries                              $   504,996    $ 1,202,604    $   134,760                   
                            Full service St-Line rent               $ 1,642,464    $ 4,769,817    $   409,872                   
                            Full service St-Line rent per sq. ft    $     29.81    $     29.72    $     29.59                   
                            % Full service St-Lined rent                   8.57%         24.89%          2.14%                  
                            Asking market rent per sq. ft                                                                       
                            No. of tenant leases expiring                     7             10              1                   
                                                                                                                                
One Memorial Drive(2)       Square feet expiring                      70,753 sf      60,840 sf      95,472 sf                   
                            Straight-Line rent                      $ 2,283,230    $ 2,027,913    $ 2,979,229                   
                            Straight-Line rent per sq. ft           $     32.27    $     33.33    $     31.21                   
                            Recoveries                              $    76,568    $   155,547    $   134,499                   
                            Full service St-Line rent               $ 2,359,798    $ 2,183,460    $ 3,113,728                   
                            Full service St-Line rent per sq. ft    $     33.35    $     35.89    $     32.61                   
                            % Full service St-Lined rent                  19.12%         17.69%         25.23%                  
                            Asking market rent per sq. ft                                                                       
                            No. of tenant leases expiring                     5              2              2                   
                                                                                                                                
201 California Street(2)    Square feet expiring                       1,664 sf      78,783 sf                                  
                            Straight-Line rent                      $    53,244    $ 2,201,376                                  
                            Straight-Line rent per sq. ft           $     32.00    $     27.94                                  
                            Recoveries                              $       192    $   141,900                                  
                            Full service St-Line rent               $    53,436    $ 2,343,276                                  
                            Full service St-Line rent per sq. ft    $     32.11    $     29.74                                  
                            % Full service St-Lined rent                   0.84%         36.74%                                 
                            Asking market rent per sq. ft                                                                       
                            No. of tenant leases expiring                     1              2                                  
                                                                                                                                
Wilshire Palisades(2)       Square feet expiring                      72,506 sf                     14,921 sf                   
                            Straight-Line rent                      $ 2,399,244                   $   703,680                   
                            Straight-Line rent per sq. ft           $     33.09                   $     47.16                   
                            Recoveries                              $    37,800                   $      --                     
                            Full service St-Line rent               $ 2,437,044                   $   703,680                   
                            Full service St-Line rent per sq. ft    $     33.61                   $     47.16                   
                            % Full service St-Lined rent                  29.35%                         8.47%                  
                            Asking market rent per sq. ft                                                                       
                            No. of tenant leases expiring                     6                             1                   

</TABLE>


<TABLE>  
<CAPTION>
         
                                                                                                      2008 and                  
PROPERTY                                                                 2006           2007           Beyond        Total      
- --------                                                                 ----           ----           ------        -----      
<S>                         <C>                                                      <C>           <C>             <C>          
99 Canal Center(2)          Square feet expiring                                                    1,760 sf     136,981 sf       
                            Straight-Line rent                                                   $    44,316    $ 3,194,700       
                            Straight-Line rent per sq. ft                                        $     25.18    $     23.32       
                            Recoveries                                                           $      --      $   118,536       
                            Full service St-Line rent                                            $    44,316    $ 3,313,236       
                            Full service St-Line rent per sq. ft                                 $     25.18    $     24.19       
                            % Full service St-Lined rent                                                1.34%        100.00%      
                            Asking market rent per sq. ft                                                                         
                            No. of tenant leases expiring                                                  1             18       
                                                                                                                                  
TransPotomac Plaza 5(2)     Square feet expiring                                    17,670 sf      19,610 sf      92,982 sf       
                            Straight-Line rent                                    $   431,688    $   438,561    $ 1,989,969       
                            Straight-Line rent per sq. ft                         $     24.43    $     22.36    $     21.40       
                            Recoveries                                            $     3,180    $      --      $    14,376       
                            Full service St-Line rent                             $   434,868    $   438,561    $ 2,004,345       
                            Full service St-Line rent per sq. ft                  $     24.61    $     22.36    $     21.56       
                            % Full service St-Lined rent                                21.70%         21.88%        100.00%      
                            Asking market rent per sq. ft                                                                         
                            No. of tenant leases expiring                                   2              1             11       
                                                                                                                                  
Sixty State Street(2)       Square feet expiring                     35,537 sf      31,600 sf     331,173 sf     815,278 sf       
                            Straight-Line rent                      $1,085,482    $   925,037    $ 8,529,321    $20,828,473       
                            Straight-Line rent per sq. ft           $    30.55    $     29.27    $     25.75    $     25.55       
                            Recoveries                              $   57,248    $   331,318    $ 4,330,778    $ 7,240,526       
                            Full service St-Line rent               $1,142,730    $ 1,256,355    $12,860,099    $28,068,999       
                            Full service St-Line rent per sq. ft    $    32.16    $     39.76    $     38.83    $     34.43       
                            % Full service St-Lined rent                  4.07%          4.48%         45.82%        100.00%      
                            Asking market rent per sq. ft                                                                         
                            No. of tenant leases expiring                    2              4              3             36       
                                                                                                                                  
Corporate 500 Centre(1)     Square feet expiring                    135,590 sf      43,140 sf     110,201 sf     617,356 sf       
                            Straight-Line rent                      $3,131,604    $   924,420    $ 2,588,964    $13,835,514       
                            Straight-Line rent per sq. ft           $    23.10    $     21.43    $     23.49    $     22.41       
                            Recoveries                              $1,251,852    $   332,760    $ 1,078,881    $ 5,327,900       
                            Full service St-Line rent               $4,383,456    $ 1,257,180    $ 3,667,845    $19,163,414       
                            Full service St-Line rent per sq. ft    $    32.33    $     29.14    $     33.28    $     31.04       
                            % Full service St-Lined rent                 22.87%          6.56%         19.14%        100.00%      
                            Asking market rent per sq. ft                                                                         
                            No. of tenant leases expiring                    1              2              2             40       
                                                                                                                                  
One Memorial Drive(2)       Square feet expiring                                    42,740 sf      55,763 sf     354,864 sf       
                            Straight-Line rent                                    $ 1,424,328    $ 2,302,691    $11,705,904       
                            Straight-Line rent per sq. ft                         $     33.33    $     41.29    $     32.99       
                            Recoveries                                            $    25,987    $   176,283    $   634,193       
                            Full service St-Line rent                             $ 1,450,315    $ 2,478,974    $12,340,097       
                            Full service St-Line rent per sq. ft                  $     33.93    $     44.46    $     34.77       
                            % Full service St-Lined rent                                11.75%         20.09%        100.00%      
                            Asking market rent per sq. ft                                                                         
                            No. of tenant leases expiring                                   1              1             13       
                                                                                                                                  
201 California Street(2)    Square feet expiring                                                                 240,230 sf       
                            Straight-Line rent                                                                  $ 5,806,932       
                            Straight-Line rent per sq. ft                                                       $     24.17       
                            Recoveries                                                                          $   571,896       
                            Full service St-Line rent                                                           $ 6,378,828       
                            Full service St-Line rent per sq. ft                                                $     26.55       
                            % Full service St-Lined rent                                                             100.00%      
                            Asking market rent per sq. ft                                                       
                            No. of tenant leases expiring                                                                 8       
                                                                                                                                  
Wilshire Palisades(2)       Square feet expiring                                    20,389 sf                    185,698 sf       
                            Straight-Line rent                                    $   877,308                   $ 7,885,056       
                            Straight-Line rent per sq. ft                         $     43.03                   $     42.46       
                            Recoveries                                            $    40,212                   $   417,960       
                            Full service St-Line rent                             $   917,520                   $ 8,303,016       
                            Full service St-Line rent per sq. ft                  $     45.00                   $     44.71       
                            % Full service St-Lined rent                                11.05%                       100.00%      
                            Asking market rent per sq. ft                                                                         
                            No. of tenant leases expiring                                   1                            16       
</TABLE>

<PAGE>

<TABLE>
<CAPTION>

                                                                         Q4
PROPERTY                                                                1998           1999          2000            2001       
- --------                                                                ----           ----          ----            ----       
<S>                         <C>                                     <C>            <C>            <C>            <C>          
All Properties Total        Square feet expiring(3)                  124,866 sf     770,738 sf     678,576 sf     953,264 sf    
                            Straight-Line rent(4)                   $ 3,178,033    $17,761,286    $13,182,071    $27,685,262    
                            Straight-Line rent per sq. ft           $     25.45    $     23.04    $     19.43    $     29.04    
                            Recoveries (5)                          $   349,391    $ 3,628,427    $ 4,205,921    $ 4,856,935    
                            Full service St-Line rent(6)            $ 3,527,424    $21,389,713    $17,387,992    $32,542,197    
                            Full service St-Line rent per sq. ft    $     28.25    $     27.75    $     25.62    $     34.14    
                            % Full service St-Lined rent                   1.04%          6.31%          5.13%          9.60%   
                            Asking market rent per sq. ft.(7)       $     35.48
                            No. of tenant leases expiring(8)                 39             81             94             97    
</TABLE>

<TABLE>
<CAPTION>
         
         
PROPERTY                                                               2002           2003           2004            2005    
- --------                                                               ----           ----           ----            ----    
<S>                         <C>                                     <C>            <C>            <C>                       
All Properties Total        Square feet expiring(3)                 1,355,931 sf   1,734,588 sf    895,523 sf     275,301 sf    
                            Straight-Line rent(4)                   $27,807,656    $38,115,614    $20,971,731    $ 8,055,470    
                            Straight-Line rent per sq. ft           $     20.51    $     21.97    $     23.42    $     29.26    
                            Recoveries (5)                          $ 8,520,307    $11,655,247    $ 4,475,975    $ 2,342,157    
                            Full service St-Line rent(6)            $36,327,963    $49,770,861    $25,447,706    $10,397,627    
                            Full service St-Line rent per sq. ft    $     26.79    $     28.69    $     28.42    $     37.77    
                            % Full service St-Lined rent                  10.72%         14.69%          7.51%          3.07%   
                            Asking market rent per sq. ft.(7)                                                                   
                            No. of tenant leases expiring(8)                110             97             53             18    
</TABLE>


<TABLE>  
<CAPTION>
         
                                                                                                      2008 and                  
PROPERTY                                                                 2006           2007           Beyond        Total      
- --------                                                                 ----           ----           ------        -----      
<S>                         <C>                                     <C>           <C>             <C>           <C>
All Properties Total        Square feet expiring(3)                  713,355 sf    742,294 sf    2,862,157 sf    11,106,593 sf
                            Straight-Line rent(4)                   $19,829,632   $15,916,661     $68,006,732     $260,510,148
                            Straight-Line rent per sq. ft           $     27.80   $     21.44     $     23.76    $       23.46
                            Recoveries (5)                          $ 5,895,405   $ 5,065,698     $27,395,203    $  78,390,666
                            Full service St-Line rent(6)            $25,725,037   $20,982,359     $95,401,935    $ 338,900,814
                            Full service St-Line rent per sq. ft    $     36.06   $     28.27     $     33.33    $       30.51
                            % Full service St-Lined rent                   7.59%         6.19%          28.15%          100.00%
                            Asking market rent per sq. ft.(7)                                                                   
                            No. of tenant leases expiring(8)                 15            27              37              668
                                                                    

</TABLE>

- ----------

*    Includes 4,605 square feet of retail space leased to the Gap at a base rent
     of $1,001,028 and recoveries of $5,524, totalling to a full service rent of
     $1,006,552.

<PAGE>

                           Cornerstone Properties Inc.
                            Lease Expiration Schedule
                                    Footnotes




- ----------------------------

(1)      Net Lease building.

(2)      Gross Lease building.

(3)      The total square footage expiring in any particular year.

(4)      Straight-line rent is the annual average of all lease payments required
         to be made through the term of the lease as required under Generally
         Accepted Accounting Principles.

(5)      The actual recovery of operating expenses annualized as of September
         30, 1998 in net lease buildings and the recovery of operating expense
         escalations annualized in gross lease buildings.

(6)      Full Service Straight-Line Rent is Straight-Line Rent plus recoveries.

(7)      Asking market rent is the average initially quoted rent to prospective
         tenants in each building. All market rents shown are on full service
         basis.

(8)      The number of tenant leases expiring in each year.





<PAGE>



                           Cornerstone Properties Inc.





                           Supplemental Information to

                           Quarterly Earnings Release









                           -  Tenant Retention Schedule






<PAGE>



                           Cornerstone Properties Inc.
                            Tenant Retention Schedule
                            As of September 30, 1998

The attached table sets forth the Company's tenant retention on expiring leases
since January 1, 1994. The analysis is based upon the percentage of expiring
leases in the applicable building with a tenant or subtenant being retained in
the expiring space, or an existing tenant expanding into the expiring space. A
tenant's lease is added to the retention schedule at the time a lease extension
is signed with the tenant, or the tenant notifies the Company of an option being
exercised.



<TABLE>
<CAPTION>
                                      1994                      1995                    1996                          1997         
                          ------------------------  ------------------------  -----------------------    --------------------------
                            sq ft    sq ft           sq ft     sq ft           sq ft    sq ft              sq ft     sq ft         
                          retained   expir.  ret %  retained   expir.  ret %  retained  expir.   ret %   retained    expir.   ret %
                          --------  -------  -----  --------  -------  -----  --------  ------   -----   --------    ------   -----
<S>                       <C>       <C>      <C>    <C>       <C>      <C>    <C>       <C>      <C>     <C>        <C>         <C>
One Norwest Center         93,962    94,981   99%    64,627    71,364   91%    43,601    72,903   60%     266,021    313,612    85%
Norwest Center             16,293    26,317   62%    22,762    23,792   96%     4,336     9,777   44%     205,749    234,260    88%
Washington Mutual Tower   127,334   153,645   83%    29,547    44,742   66%    86,956   106,250   82%     182,194    207,738    88%
125 Summer Street                                                              95,816    96,658   99%      41,252     62,218    66%
Tower 56                                                                       46,003    53,762   86%      37,027     50,679    73%
One Lincoln Centre                                                                                         35,320     42,099    84%
527 Madison Avenue                                                                                          5,980     20,587    29%
191 Peachtree Street                                                                                         --         --     --
Market Square                                                                                                --         --     --
500 Boylston Street                                                                                          --        3,005     0%
222 Berkeley Street                                                                                          --         --     --
Charlotte Plaza                                                                                             2,974      6,390    47%
200 Galleria                                                                                               10,672     21,725     9%
11 Canal Center                                                                                              --        8,889     0%
99 Canal Center                                                                                              --         --     --
TransPotomac Plaza 5                                                                                         --         --     --
Sixty State Street                                                                                           --         --     --
Corporate 500 Centre                                                                                         --         --     --
One Memorial Drive                                                                                           --         --     --
201 California Street                                                                                        --         --     --
Wilshire Palisades                                                                                           --         --     --
                          ------------------------  ------------------------  ------------------------    -------------------------
Weighted                  237,589   274,943   86%   116,936   139,898   84%   276,712   339,350   82%     787,189    971,202    81%
</TABLE>

<TABLE>
<CAPTION>
                                         YTD 1998 (Q3)          
                               ---------------------------------
                                sq ft      sq ft                
                               retained    expir.          ret %
                               --------    -------         -----
<S>                            <C>        <C>              <C>  
One Norwest Center              72,170     100,275          72%   
Norwest Center                 101,382     111,786          91% 
Washington Mutual Tower        321,619     323,056         100% 
125 Summer Street              110,447     131,458          84% 
Tower 56                        16,790      16,790         100% 
One Lincoln Centre              31,166      84,750          37% 
527 Madison Avenue              10,277      10,419          99% 
191 Peachtree Street            25,617     112,635          23% 
Market Square                   27,279      41,241          66% 
500 Boylston Street             72,628      72,628         100% 
222 Berkeley Street             44,527      44,527         100% 
Charlotte Plaza                 30,601      53,503          57% 
200 Galleria                    37,404      56,488          66% 
11 Canal Center                   --          --          --    
99 Canal Center                 29,925      33,918          88% 
TransPotomac Plaza 5             6,745      17,185          39% 
Sixty State Street             115,178     120,503          96% 
Corporate 500 Centre            22,559      66,745          34% 
One Memorial Drive                --          --          --    
201 California Street             --          --          --    
Wilshire Palisades              16,237      16,237         100% 
                             ----------------------------------
Weighted                     1,092,551   1,414,144          77% 

                            Five year total                 80%
                                                         ------
                                                         ------
</TABLE>
<PAGE>





                           Cornerstone Properties Inc.




                           Supplemental Information to

                           Quarterly Earnings Release









                           - Leasing Costs and Capital Expenditures



<PAGE>

Incremental Revenue Generating Leasing Costs and Capital Expenditures

The following table shows Historical Incremental Revenue Generating Leasing
Costs, which are the leasing costs (tenant improvements and leasing commissions)
required to lease (i) first generation space on development properties and (ii)
space which was vacant at the time of the acquisition of a property which will
increase the overall return on the property. Additionally, the table shows
Historical Incremental Revenue Generating Capital Expenditures, which are
Capital Expenditures expended to increase the the profitability of the building
either through the generation of higher earnings capability, or by improving
building system efficiency, thus producing lower operating expenses
prospectively.



<TABLE>
<CAPTION>
                                               YTD 1998        1997         1996          1995           1994         Total
<S>                                         <C>            <C>          <C>           <C>            <C>         <C>
One Norwest Center
Total Tenant Lease Costs                        24,169          --            --            --            --          24,169
Total Square Feet Leased                         1,497          --            --            --            --           1,497
Total Per Square Foot                            16.14          --            --            --            --           16.14
Capital Expenditures                              --            --            --            --            --            --

Norwest Center
Total Tenant Lease Costs                          --            --            --            --            --            --
Total Square Feet Leased                          --            --            --            --            --            --
Total Per Square Foot                             --            --            --            --            --            --
Capital Expenditures                              --            --            --            --            --            --

Washington Mutual Tower
Total Tenant Lease Costs                          --         404,988       643,235          --            --       1,048,223
Total Square Feet Leased                          --          69,727       146,517          --            --         216,244
Total Per Square Foot                             --            5.81          4.39          --            --            4.85
Capital Expenditures                              --          88,401        25,500       135,194       102,567       351,662

125 Summer Street
Total Tenant Lease Costs                          --            --         369,727          --            --         369,727
Total Square Feet Leased                          --            --          33,136          --            --          33,136
Total Per Square Foot                             --            --           11.16          --            --           11.16
Capital Expenditures                              --            --            --            --            --            --

Tower 56
Total Tenant Lease Costs                          --            --         174,266          --            --         174,266
Total Square Feet Leased                          --            --           7,115          --            --           7,115
Total Per Square Foot                             --            --           24.49          --            --           24.49
Capital Expenditures                              --            --            --            --            --            --

One Lincoln Centre
Total Tenant Lease Costs                       141,687       261,538         9,706          --            --         412,931
Total Square Feet Leased                         6,021        11,816         1,941          --            --          19,778
Total Per Square Foot                            23.53         22.13          5.00          --            --           20.88
Capital Expenditures                            25,298        61,877          --            --            --          87,175

527 Madison Avenue
Total Tenant Lease Costs                          --            --            --            --            --            --
Total Square Feet Leased                          --            --            --            --            --            --
Total Per Square Foot                             --            --            --            --            --            --
Capital Expenditures                              --            --            --            --            --            --

191 Peachtree Street
Total Tenant Lease Costs                     1,542,393          --                          --            --       1,542,393
Total Square Feet Leased                        40,238          --            --            --            --          40,238
Total Per Square Foot                            38.33          --            --            --            --           38.33
Capital Expenditures                            86,968          --            --            --            --          86,968

Market Square
Total Tenant Lease Costs                       445,933          --            --            --            --         445,933
Total Square Feet Leased                        10,054          --            --            --            --          10,054
Total Per Square Foot                            44.35          --            --            --            --           44.35
Capital Expenditures                              --            --            --            --            --            --

500 Boylston Street
Total Tenant Lease Costs                          --            --            --            --            --            --
Total Square Feet Leased                          --            --            --            --            --            --
Total Per Square Foot                             --            --            --            --            --            --
Capital Expenditures                              --            --            --            --            --            --

222 Berkeley Street
Total Tenant Lease Costs                          --            --            --            --            --            --
Total Square Feet Leased                          --            --            --            --            --            --
Total Per Square Foot                             --            --            --            --            --            --
Capital Expenditures                              --            --            --            --            --            --
</TABLE>

<PAGE>

Incremental Revenue Generating Leasing Costs and Capital Expenditures

The following table shows Historical Incremental Revenue Generating Leasing
Costs, which are the leasing costs (tenant improvements and leasing commissions)
required to lease (i) first generation space on development properties and (ii)
space which was vacant at the time of the acquisition of a property which will
increase the overall return on the property. Additionally, the table shows
Historical Incremental Revenue Generating Capital Expenditures, which are
Capital Expenditures expended to increase the the profitability of the building
either through the generation of higher earnings capability, or by improving
building system efficiency, thus producing lower operating expenses
prospectively.

<TABLE>
<CAPTION>
                                               YTD 1998        1997         1996          1995           1994         Total
<S>                                         <C>            <C>          <C>           <C>            <C>         <C>
Charlotte Plaza
Total Tenant Lease Costs                       115,602          --            --            --            --         115,602
Total Square Feet Leased                        26,820          --            --            --            --          26,820
Total Per Square Foot                             4.31          --            --            --            --            4.31
Capital Expenditures                           341,839          --            --            --            --         341,839

200 Galleria
Total Tenant Lease Costs                       301,998        24,132          --            --            --         326,130
Total Square Feet Leased                        15,198         2,139          --            --            --          17,337
Total Per Square Foot                            19.87         11.28          --            --            --           18.81
Capital Expenditures                              --            --                          --            --            --

11 Canal Center
Total Tenant Lease Costs                       185,633          --            --            --            --         185,633
Total Square Feet Leased                         8,889          --            --            --            --           8,889
Total Per Square Foot                            20.88          --            --            --            --           20.88
Capital Expenditures                              --         102,986          --            --            --         102,986

99 Canal Center
Total Tenant Lease Costs                          --            --            --            --            --            --
Total Square Feet Leased                          --            --            --            --            --            --
Total Per Square Foot                             --            --            --            --            --            --
Capital Expenditures                              --          51,419          --            --            --          51,419

TransPotomac Plaza 5
Total Tenant Lease Costs                        24,968          --            --            --            --          24,968
Total Square Feet Leased                         4,453          --            --            --            --           4,453
Total Per Square Foot                             5.61          --            --            --            --            5.61
Capital Expenditures                              --          62,579          --            --            --          62,579

Sixty State Street
Total Tenant Lease Costs                          --            --            --            --            --            --
Total Square Feet Leased                          --            --            --            --            --            --
Total Per Square Foot                             --            --            --            --            --            --
Capital Expenditures                             8,970          --            --            --            --           8,970

Corporate 500 Centre
Total Tenant Lease Costs                        72,834          --            --            --            --          72,834
Total Square Feet Leased                         4,902          --            --            --            --           4,902
Total Per Square Foot                            14.86          --            --            --            --           14.86
Capital Expenditures                              --            --            --            --            --            --

One Memorial Drive
Total Tenant Lease Costs                          --            --            --            --            --            --
Total Square Feet Leased                          --            --            --            --            --            --
Total Per Square Foot                             --            --            --            --            --            --
Capital Expenditures                              --            --            --            --            --            --

201 California Street
Total Tenant Lease Costs                          --            --            --            --            --            --
Total Square Feet Leased                          --            --            --            --            --            --
Total Per Square Foot                             --            --            --            --            --            --
Capital Expenditures                              --            --            --            --            --            --

Wilshire Palisades
Total Tenant Lease Costs                          --            --            --            --            --            --
Total Square Feet Leased                          --            --            --            --            --            --
Total Per Square Foot                             --            --            --            --            --            --
Capital Expenditures                            24,850          --            --            --            --          24,850
</TABLE>

<PAGE>

Incremental Revenue Generating Leasing Costs and Capital Expenditures

The following table shows Historical Incremental Revenue Generating Leasing
Costs, which are the leasing costs (tenant improvements and leasing commissions)
required to lease (i) first generation space on development properties and (ii)
space which was vacant at the time of the acquisition of a property which will
increase the overall return on the property. Additionally, the table shows
Historical Incremental Revenue Generating Capital Expenditures, which are
Capital Expenditures expended to increase the the profitability of the building
either through the generation of higher earnings capability, or by improving
building system efficiency, thus producing lower operating expenses
prospectively.



<TABLE>
<CAPTION>
                                               YTD 1998        1997         1996          1995           1994         Total
<S>                                         <C>            <C>          <C>           <C>            <C>         <C>
Minority Interest*
Total Tenant Lease Costs                          --            --            --            --            --            --
Total Square Feet Leased                          --            --            --            --            --            --
Total Per Square Foot                             --            --            --            --            --            --
Capital Expenditures                              --            --            --            --            --            --

Total Cornerstone Portfolio
Total Tenant Lease Costs                     2,855,217       690,658     1,196,934          --            --       4,742,809
Total Square Feet Leased                       118,072        83,682       188,709          --            --         390,463
Total Per Square Foot Leased                     24.18          8.25          6.34          --            --           12.15

Capital Expenditures                           488,056       367,262        25,500       135,194       102,567     1,118,579
Weighted Average Square Footage Owned**      7,644,000     5,348,000     3,895,680     3,263,769     3,239,636    23,391,085
Total Per Square Foot                             0.06          0.07          0.01          0.04          0.03          0.05
</TABLE>

*    Adjustments for minority interests at Norwest Center (19.0%), 500 Boylston
     (8.5%) and 222 Berkeley (8.5%)

**   Square footage owned is adjusted for minority interests as described above

<PAGE>


Non Incremental Revenue Generating Leasing Costs and Capital Expenditures

The following table shows Historical Non-Incremental Revenue Generating Leasing
Costs, which are the leasing costs (tenant improvements and leasing
commissions), in total and on a per square foot basis, to re-lease expiring
leases or renew or extend existing leases. The Company believes that its ability
to renew and extend existing tenants at a high percentage has substantially
reduced its overall leasing costs on a per square foot basis. Additionally, the
table shows Historical Non-Incremental Revenue Generating Capital Expenditures,
which are Capital Expenditures expended to maintain a property in a Class A
manner and do not give rise to additional earnings capacity, but rather allow
the property to maintain its competitive position within its market. The Company
believes that its focus on continuing high level of maintenance of its assets
has greatly reduced the amount of Capital Expenditures required at its
buildings.


<TABLE>
<CAPTION>
                                              YTD 1998       1997           1996          1995          1994        Total
<S>                                         <C>            <C>          <C>           <C>            <C>         <C>
One Norwest Center
Total Tenant Lease Costs                       193,549     1,823,664     1,009,006       141,135       540,444     3,707,798
Total Square Feet Leased                        75,989       308,697        81,445        75,939       117,966       660,036
Total Per Square Foot                             2.55          5.91         12.39          1.86          4.58          5.62
Capital Expenditures                              --         102,000          --            --            --         102,000

Norwest Center
Total Tenant Lease Costs                       558,040       569,103        42,237       144,275        30,193     1,343,848
Total Square Feet Leased                       116,966       212,795         6,629        24,986        26,939       388,315
Total Per Square Foot                             4.77          2.67          6.37          5.77          1.12          3.46
Capital Expenditures                              --          10,974          --            --            --          10,974

Washington Mutual Tower
Total Tenant Lease Costs                     1,634,183     1,204,606       793,361       290,971     1,065,962     4,989,083
Total Square Feet Leased                       346,317       208,875       124,474        53,894       151,051       884,611
Total Per Square Foot                             4.72          5.77          6.37          5.40          7.06          5.64
Capital Expenditures                             3,579        21,922          --            --          50,801        76,302

125 Summer Street
Total Tenant Lease Costs                       894,738     1,314,489     2,158,339          --            --       4,367,566
Total Square Feet Leased                       119,242        65,105       117,794          --            --         302,141
Total Per Square Foot                             7.50         20.19         18.32          --            --           14.46
Capital Expenditures                            22,322        53,185       518,632          --            --         594,139

Tower 56
Total Tenant Lease Costs                       260,994       724,025       339,124          --            --       1,324,143
Total Square Feet Leased                        24,955        65,283        42,203          --            --         132,441
Total Per Square Foot                            10.46         11.09          8.04          --            --           10.00
Capital Expenditures                              --          43,538          --            --            --          43,538

One Lincoln Centre
Total Tenant Lease Costs                       220,028       287,758         2,859          --            --         510,645
Total Square Feet Leased                        61,099        42,826         3,652          --            --         107,577
Total Per Square Foot                             3.60          6.72          0.78          --            --            4.75
Capital Expenditures                            37,468       154,646          --            --            --         192,114

527 Madison Avenue
Total Tenant Lease Costs                       125,356       746,070          --            --            --         871,426
Total Square Feet Leased                        10,277        29,821          --            --            --          40,098
Total Per Square Foot                            12.20         25.02          --            --            --           21.73
Capital Expenditures                           488,165        86,652          --            --            --         574,817

191 Peachtree Street
Total Tenant Lease Costs                       566,508        96,023          --            --            --         662,531
Total Square Feet Leased                       106,972         2,597          --            --            --         109,569
Total Per Square Foot                             5.30         36.97          --            --            --            6.05
Capital Expenditures                              --            --            --            --            --            --

Market Square
Total Tenant Lease Costs                       390,704          --            --            --            --         390,704
Total Square Feet Leased                        27,279          --            --            --            --          27,279
Total Per Square Foot                            14.32          --            --            --            --           14.32
Capital Expenditures                              --            --            --            --            --            --

500 Boylston Street
Total Tenant Lease Costs                        52,289        34,558          --            --            --          86,847
Total Square Feet Leased                        72,628         3,005          --            --            --          75,633
Total Per Square Foot                             0.72         11.50          --            --            --            1.15
Capital Expenditures                              --            --            --            --            --            --

222 Berkeley Street
Total Tenant Lease Costs                       541,372          --            --            --            --         541,372
Total Square Feet Leased                        44,852          --            --            --            --          44,852
Total Per Square Foot                            12.07          --            --            --            --           12.07
Capital Expenditures                              --            --            --            --            --            --
</TABLE>

<PAGE>

Non Incremental Revenue Generating Leasing Costs and Capital Expenditures

The following table shows Historical Non-Incremental Revenue Generating Leasing
Costs, which are the leasing costs (tenant improvements and leasing
commissions), in total and on a per square foot basis, to re-lease expiring
leases or renew or extend existing leases. The Company believes that its ability
to renew and extend existing tenants at a high percentage has substantially
reduced its overall leasing costs on a per square foot basis. Additionally, the
table shows Historical Non-Incremental Revenue Generating Capital Expenditures,
which are Capital Expenditures expended to maintain a property in a Class A
manner and do not give rise to additional earnings capacity, but rather allow
the property to maintain its competitive position within its market. The Company
believes that its focus on continuing high level of maintenance of its assets
has greatly reduced the amount of Capital Expenditures required at its
buildings.


<TABLE>
<CAPTION>
                                              YTD 1998       1997           1996          1995          1994        Total
<S>                                         <C>            <C>          <C>           <C>            <C>         <C>
Charlotte Plaza
Total Tenant Lease Costs                       457,223       154,044          --            --            --         611,267
Total Square Feet Leased                        53,663         9,139          --            --            --          62,802
Total Per Square Foot                             8.52         16.86          --            --            --            9.73
Capital Expenditures                             5,086        15,039          --            --            --          20,125

200 Galleria
Total Tenant Lease Costs                       531,720       173,242          --            --            --         704,962
Total Square Feet Leased                        53,585        10,672          --            --            --          64,257
Total Per Square Foot                             9.92         16.23          --            --            --           10.97
Capital Expenditures                           125,971          --            --            --            --         125,971

11 Canal Center
Total Tenant Lease Costs                          --            --            --            --            --            --
Total Square Feet Leased                          --            --            --            --            --            --
Total Per Square Foot                             --            --            --            --            --            --
Capital Expenditures                            18,437          --            --            --            --          18,437

99 Canal Center
Total Tenant Lease Costs                       165,899          --            --            --            --         165,899
Total Square Feet Leased                        33,918          --            --            --            --          33,918
Total Per Square Foot                             4.89          --            --            --            --            4.89
Capital Expenditures                            21,012          --            --            --            --          21,012

TransPotomac Plaza 5
Total Tenant Lease Costs                       214,177          --            --            --            --         214,177
Total Square Feet Leased                        17,185          --            --            --            --          17,185
Total Per Square Foot                            12.46          --            --            --            --           12.46
Capital Expenditures                              --            --            --            --            --

Sixty State Street
Total Tenant Lease Costs                     5,125,892          --            --            --            --       5,125,892
Total Square Feet Leased                       129,778          --            --            --            --         129,778
Total Per Square Foot                            39.50          --            --            --            --           39.50
Capital Expenditures                           173,595          --            --            --            --         173,595

Corporate 500 Centre
Total Tenant Lease Costs                       399,250          --            --            --            --         399,250
Total Square Feet Leased                        37,713          --            --            --            --          37,713
Total Per Square Foot                            10.59          --            --            --            --           10.59
Capital Expenditures                            43,259          --            --            --            --          43,259

One Memorial Drive
Total Tenant Lease Costs                          --            --            --            --            --            --
Total Square Feet Leased                          --            --            --            --            --            --
Total Per Square Foot                             --            --            --            --            --            --
Capital Expenditures                              --            --            --            --            --            --

201 California Street
Total Tenant Lease Costs                          --            --            --            --            --            --
Total Square Feet Leased                          --            --            --            --            --            --
Total Per Square Foot                             --            --            --            --            --            --
Capital Expenditures                              --            --            --            --            --            --

Wilshire Palisades
Total Tenant Lease Costs                       113,087          --            --            --            --         113,087
Total Square Feet Leased                        19,106          --            --            --            --          19,106
Total Per Square Foot                             5.92          --            --            --            --            5.92
Capital Expenditures                           241,084          --            --            --            --         241,084
</TABLE>

<PAGE>


Non Incremental Revenue Generating Leasing Costs and Capital Expenditures

The following table shows Historical Non-Incremental Revenue Generating Leasing
Costs, which are the leasing costs (tenant improvements and leasing
commissions), in total and on a per square foot basis, to re-lease expiring
leases or renew or extend existing leases. The Company believes that its ability
to renew and extend existing tenants at a high percentage has substantially
reduced its overall leasing costs on a per square foot basis. Additionally, the
table shows Historical Non-Incremental Revenue Generating Capital Expenditures,
which are Capital Expenditures expended to maintain a property in a Class A
manner and do not give rise to additional earnings capacity, but rather allow
the property to maintain its competitive position within its market. The Company
believes that its focus on continuing high level of maintenance of its assets
has greatly reduced the amount of Capital Expenditures required at its
buildings.


<TABLE>
<CAPTION>
                                              YTD 1998       1997           1996          1995          1994        Total
<S>                                         <C>            <C>          <C>           <C>            <C>         <C>
Minority Interest*
Total Tenant Lease Costs                     156,488.79      123,622         9,208        30,442         5,978       325,739
Total Square Feet Leased                      32,209.34       44,382         1,372         5,172         5,576        88,712
Total Per Square Foot                              4.86         2.79          6.71          5.89          1.07          3.67
Capital Expenditures                              --           2,272          --            --            --           2,272

Total Cornerstone Portfolio
Total Tenant Lease Costs                     12,288,520    7,003,960     4,335,718       545,939     1,630,621    25,804,758
Total Square Feet Leased                      1,319,315      914,433       374,825       149,647       290,380     3,048,599
Total Per Square Foot Leased                       9.31         7.66         11.57          3.65          5.62          8.46

Capital Expenditures                          1,179,978      485,684       518,632          --          50,801     2,235,095
Weighted Average Square Footage Owned**       7,644,000    5,348,000     3,895,680     3,263,769     3,239,636    23,391,085
Total Per Square Foot                              0.15         0.09          0.13          --            0.02          0.10
</TABLE>

*    Adjustments for minority interests at Norwest Center (19.0%), 500 Boylston
     (8.5%) and 222 Berkeley (8.5%)

**   Square footage owned is adjusted for minority interests as described above

<PAGE>





                           Cornerstone Properties Inc.





                           Supplemental Information to

                           Quarterly Earnings Release









                                     -   Debt Schedule






<PAGE>

                           Cornerstone Properties Inc.
                                  Debt Schedule
                               September 30, 1998




The following table sets forth certain information regarding the consolidated
debt obligations of the Company as of September 30, 1998, including mortgage
obligations relating to the Properties. All of this debt, with the exception of
the Convertible Promissory Note due 2001, is nonrecourse to the Company.
However, notwithstanding the nonrecourse indebtedness, the lender may have the
right to recover deficiencies from the Company in certain circumstances,
including fraud, misappropriation of funds and environmental liabilities.

<TABLE>
<CAPTION>
                                                                         Maturity      Prepayment 
Property                               Amortization     Interest Rate      Date        Provisions        9/30/98
- --------                               ------------     -------------      ----        ----------        -------
<S>                                    <C>              <C>              <C>          <C>                <C>
Convertible Promissory Note due 2001
  (A).............................     Interest only     8.11% max (B)    Jan-2001    Not prepayable     $12,926,000
One Norwest Center (C)............     30 year           6.90 (D)         Oct-2008     (E)                98,500,000
Norwest Center....................     Interest only     8.74             Dec-2005    Not prepayable     110,000,000
Washington Mutual Tower...........     Interest only     7.53             Nov-2005     (F)                79,100,000
125 Summer Street.................     Interest only (G) 7.20             Jan-2003     (H)                50,000,000
Tower 56..........................     30 year           7.67             May-2003     (I)                17,608,000
TransPotomac Plaza 5 and Charlotte
  Plaza (J).......................     Interest only     7.28             Oct-2000    Not prepayable      65,000,000
527 Madison Avenue and One Lincoln
  Centre (J)......................     Interest only     7.47             Oct-2004    Not prepayable      65,000,000
Market Square (K) and 200
  Galleria (J)....................     Interest only     7.54             Oct-2007    Not prepayable     120,000,000
Sixty State Street (L)............     30 year           6.84             Jan-2005     (M)                88,141,000
Corporate 500 Centre (N)..........     Interest only     6.63 (O)         Jul-2002    Prepayable          80,000,000
201 California Street (P).........     30 year           6.70             Mar-2005     (Q)                33,171,000
Wilshire Palisades (R)............     30 year           6.70             Jul-2002     (S)                30,109,000
                                                         ----------------------------                   ------------
                                                         7.37 (T)         6.4 yrs. (T)                  $849,555,000
</TABLE>


Credit Line

The Company has a $350 million Revolving Credit Facility with Bankers Trust
Company and The Chase Manhattan Bank for acquisitions and general working
capital purposes as well as the issuance of letters of credit. The interest rate
on the line of credit depends on the Company's leverage ratio at the time of
borrowing and will be at a spread of 1.10% to 1.40% over LIBOR or the Prime Rate
at the borrower's option. The letters of credit will be priced at the applicable
Eurodollar credit spread. The line of credit expires on October 27, 2000. As of
September 30, 1998, $148.0 million of the credit line was outstanding at a rate
of approximately 6.79%. The line of credit contains certain restrictive
covenants including; (i) a limitation on the Company's dividend to 90% of funds
from operations and 110% of cash available for distribution; (ii) total
liabilities to total property asset value cannot exceed 55%; (iii) adjusted
EBITDA to interest expense may not be less than 2.25 to 1.00; (iv) fixed charge
coverage may not be less than 1.75 to 1.00; and (v) total property asset value
to secured indebtedness may not be less than 2.50 to 1.00.


<PAGE>

                           Cornerstone Properties Inc.
                                  Debt Schedule
                                    Footnotes

(A)      The lender, Hines, has the right to convert the note into Common Stock
         at a conversion price of $14.30 per share. At maturity, the Company is
         entitled to repay the principal of the note with Common Stock priced at
         the lesser of $14.30 per share or the then-existing share price.

(B)      Lesser of 30-day LIBOR plus 0.5% or 8.11%.

(C)      On September 25, 1998, the Company completed the refinancing of the
         $96.1 million mortgage on One Norwest Center with CIGNA and Mass
         Mutual. As a result of the refinancing, the principal balance was
         increased to $98.5 million, the term of the loan was extended from
         three years to ten years and the interest rate was reduced from 7.50%
         to 6.90%.

(D)      Weighted-average interest rate among the three notes comprising the
         $98.5 million total mortgage balance.

(E)      No prepayment until October 1, 2000. From October 1, 2000 through
         September 30, 2007, the prepayment fee is the greater of: (1) 1% of the
         outstanding principal balance or (2) Treasury Yield Maintenance (as
         defined). Beginning October 1, 2007, the prepayment fee is Treasury
         Yield Maintenance. The loan may be repaid at par during the last 90
         days of the loan.

(F)      No prepayment until September 30, 1998. Prepayable thereafter, with a
         prepayment fee equal to the greater of: (1) 1% of the outstanding
         principal balance or (2) Treasury Yield Maintenance (as defined).
         Prepayment without fee during the six months prior to the maturity
         date.

(G)      Interest only payments through January 1, 2001, with a 25-year
         amortization schedule thereafter.

(H)      Beginning July 1, 1999, the prepayment fee is the greater of Treasury
         Yield Maintenance (as defined) or 1% of the outstanding principal
         balance. Prepayment without fee on or after three months prior to
         maturity date.

(I)      Open to prepayment after December 31, 1999, with a prepayment fee equal
         to the greater of 1% of the principal balance or Treasury Yield
         Maintenance (as defined). Prepayment without fee during the three
         months prior to the maturity date.

(J)      The three notes arising from the acquisition of several properties from
         DIHC are cross-collateralized, having the effect of forming a
         "collateral pool" for the underlying notes.

(K)      The collateral for this loan is a pledge of the $181 million first
         mortgage loan on Market Square which the Company purchased from PGGM.

(L)      While the face amount of the loan is $77,938,000, and the interest rate
         is 9.5%, the Company is carrying the debt at $88,141,000, which is the
         market value of the loan at the time of the closing, less the
         amortization of principal and premium since closing, based upon a
         market interest rate for similar quality loans of 6.84%.

(M)      Beginning February 1, 2000, the prepayment fee is equal to the greater
         of: (1) 2% of the outstanding principal balance or (2) Treasury Yield
         Maintenance (as defined). The 2% maximum is reduced by 0.25% per annum
         thereafter until it reaches 1%. Prepayment without fee during the 90
         days prior to the maturity date.

(N)      On October 9, 1998, the Company completed the refinancing of the $80.0
         million mortgage on Corporate 500 Centre with Teachers Insurance and
         Annuity Association. As a result of the refinancing, the principal
         balance was increased to $90.0 million, the term of the loan was
         extended from 4.5 years to 10 years and the interest rate was increased
         by three basis points to 6.66%.

(O)      The interest rate on the loan is LIBOR plus 100 basis points.

(P)      While the face amount of the loan is $32,842,000, and the interest rate
         is 6.9%, the Company is carrying the debt at $33,171,000, which is the
         market value of the loan at the time of the closing, less the
         amortization of principal and premium since closing, based upon a
         market interest rate for similar quality loans of 6.70%.

(Q)      No prepayment until March 15, 2001. Prepayable thereafter, with a
         prepayment fee equal to the greater of: (1) 1% of the amount being
         prepaid or (2) Modified Yield Maintenance (as defined). If a partial
         prepayment is made, the prepayment fee is equal to Modified Yield
         Maintenance. Prepayment without fee during the 120 days prior to the
         maturity date.

(R)      While the face amount of the loan is $28,841,000, and the interest rate
         is 8.04%, the Company is carrying the debt at $30,109,000, which is the
         market value of the loan at the time of the closing, less the
         amortization of principal and premium since closing, based upon a
         market interest rate for similar quality loans of 6.70%.

(S)      No prepayment until July 1, 1998. Prepayable thereafter with 60 days
         notice to Lender, with a prepayment fee equal to the greater of: (1) 1%
         of the outstanding principal balance or (2) Yield Maintenance (as
         defined).

(T)      Weighted-average interest rate and maturity of the Company's long-term
         debt.

<PAGE>


                           Cornerstone Properties Inc.





                           Supplemental Information to

                           Quarterly Earnings Release









                                         -   Equity Schedule


<PAGE>


                           Cornerstone Properties Inc.
                            Equity Activity Schedule
                            As of September 30, 1998


The following table shows the equity activity that has occurred since January 1,
1998 and the calculation of fully diluted Common shares and Units outstanding:


<TABLE>
<CAPTION>
Date                          Description                                                         Number of Shares
- ----                          -----------                                                         ----------------
<S>                          <C>                                                                  <C>
COMMON STOCK
       1/1/98                Beginning balance                                                      83,191,819
       1/5/98                Tower 56 residual value acquisition                                       307,692
       2/2/98                Public secondary equity offering                                       14,375,000
      2/17/98                Management stock grants                                                    12,500
      2/27/98                Dividend reinvestment                                                     109,007
       3/2/98                Management stock grants                                                    19,178
      4/28/98                One Memorial Drive acquisition                                          3,428,571
      5/29/98                Dividend reinvestment                                                      98,487
      8/31/98                Dividend reinvestment                                                      94,610
                                                                                                   -----------
                                                                                                   101,636,864
                                                                                                   -----------
OUTSIDE UPREIT UNITS
       1/1/98                Beginning balance                                                              --
      1/29/98                Corporate 500 Centre acquisition                                          822,794
      4/28/98                One Memorial Drive acquisition                                          1,657,426
       6/3/98                201 California Street and Wilshire Palisades acquisition                1,665,663
                                                                                                   -----------
                                                                                                     4,145,883
                                                                                                   -----------
DILUTIVE ISSUES
                              Convertible Preferred Stock                                            3,030,303
                              Convertible Promissory Note                                              903,914
                              Dilutive effect of "in the money" options                                276,369
                                                                                                   -----------
                                                                                                     4,210,586
                                                                                                   -----------
       9/30/98                Total fully diluted common shares and units outstanding              109,993,333
                                                                                                   -----------
                                                                                                   -----------
                              Year to date weighted average fully diluted common
                              shares and units outstanding                                         104,939,852
                                                                                                   -----------
                                                                                                   -----------
                              Quarter to date weighted average fully diluted common
                              shares and units outstanding                                         109,930,602
                                                                                                   -----------
                                                                                                   -----------
</TABLE>

<PAGE>

                           Cornerstone Properties Inc.





                           Supplemental Information to

                           Quarterly Earnings Release









                      - Minority Sharing in Cash Flows and

                                Residual Proceeds



<PAGE>



Minority Sharing in Cash Flows and Residual Proceeds



         Five of the Company's properties are held in partnerships which allow
the Company's partners to participate in the cash flows of their respective
properties. The following discussion provides the details of partner's
participation in the cash flow of each of the respective properties.


Norwest Center

         Under the partnership agreement, cash flow is used first to pay
operating and capital expenditures, then debt service on the mortgage note. The
remaining cash flow is paid first to Cornerstone, as a 7% cumulative preference
return on its capital base of $92.3 million ($6,461,000), and then any remaining
cash flow is split 50% to Cornerstone and 50% to their partner, Sixth &
Marquette Limited Partnership ("S&M"). Should cash flow be insufficient to pay
the preference return ("Preference Deficit"), it will accumulate and earn
interest at 7%. Any Preference Deficit will be paid as the first priority
payment after debt service. Cash flow and earnings for the first nine months of
1998 were split 81.0% to Cornerstone and 19.0% to S&M. Sales proceeds from
Norwest Center will be split as follows as of September 30, 1998:

         1)       To Debt              $110.0 million
         2)       To Cornerstone         92.3 million
         3)       To Cornerstone          9.3 million
         4)       To Cornerstone          1.0 million
         5)       To S&M                 18.9 million
         6)       The remaining proceeds will be split 50/50 among the 
                  two partners.

Washington Mutual Tower

         Under the partnership agreement, cash flow is used first to pay
operating and capital expenditures, then debt service on the mortgage note. The
remaining cash flow is paid first to Cornerstone as a 9.53% preference return on
its capital base of $47.0 million ($4,479,000); next to pay the Preference
Deficit on the second preference return (currently $8.9 million); then to
Cornerstone as an 8% second preference return on its capital base of $100.0
million ($8,000,000). Any remaining cash flow is split 50% to Cornerstone and
50% to 1212. The cumulative Preference Deficit earns interest at a rate of 8%
until it is repaid. Cornerstone's partner, 1212 Partnership, does not currently
share in the cash flow from Washington Mutual Tower. With regard to the sale of
the building, the Company will receive the first $155.9 million of proceeds
after repayment of the $79.1 million mortgage ($235.0 million in total
proceeds). Any proceeds above this amount will be split 50/50 with Cornerstone's
partners.




<PAGE>


Minority Sharing in Cash Flows and Residual Proceeds (continued)


191 Peachtree Street

         Under the partnership agreement, cash flow is used first to pay
operating and capital expenditures, then debt service on the mortgage note. In
addition, the partner in the transaction, CH Associates, Ltd., will receive an
annual incentive distribution of $250,000 which Cornerstone expects it will
receive under the partnership agreement through February 28, 2000. Cornerstone
receives the remaining cash flow until such time as its cumulative undistributed
preferred return ($161.1 million as of 9/30/98) has been reimbursed. Excess cash
flow will be split 80% to Cornerstone and 20% to CH Associates, Ltd. Sales
proceeds from 191 Peachtree Street will be split as follows as of September 30,
1998:
        1)     To Debt                                     $  1.8 million
        2)     To Cornerstone (as partial holder
               of the debt)                                $159.5 million
        3)     To Cornerstone for its undistributed
               preferred return                            $ 16.1 million
        4)     To Cornerstone for its priority capital
               contribution                                $145.0 million


500 Boylston and 222 Berkeley Street

         Distributions of cash flows and sales proceeds are shared in proportion
to Cornerstone's 91.5% partnership interest and Hines' 8.5% partnership
interest.



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