BOK FINANCIAL CORP ET AL
424B5, 1999-06-23
NATIONAL COMMERCIAL BANKS
Previous: AES CORPORATION, 424B3, 1999-06-23
Next: CARDIAC SCIENCE INC, SC 13D/A, 1999-06-23



<PAGE>   1
                                                Filed pursuant to rule 424(b)(5)
                                                Registration No. 333-65629


                   SUBJECT TO COMPLETION, DATED JUNE 22, 1999

Preliminary Prospectus Supplement (to Prospectus dated October 12, 1998)

                                  $100,000,000

                           [BOK FINANCIAL CORP. LOGO]

                            [      ]% NOTES DUE 200

MATURITY

- - The Notes will mature on             , 200 .

INTEREST

- - Interest on the Notes is payable semi-annually on             and
  of each year, beginning                .

- - Interest will accrue from             , 1999.

RANKING

- - The Notes are unsecured and rank equally with all of our existing and future
  senior unsecured debt and senior to all of our existing and future
  subordinated debt.

REDEMPTION

- - We may not redeem the Notes prior their to maturity.

- - There is no sinking fund.

THE COMPANY

- - We are a bank holding company. Through our significant operating subsidiaries,
  we offer a broad array of financial products and services.

- - Our principal office is located at Bank of Oklahoma Tower, Boston Avenue at
  Second Street, Tulsa, Oklahoma 74172. Our telephone number is (918) 588-6752.

THE OFFERING

- - The Notes will be delivered to you in global form through the book-entry
  delivery system of The Depository Trust Company on or about             ,
  1999.

- - The Underwriters listed below will purchase the Notes from us on a firm
  commitment basis and offer them to you, subject to certain conditions.

LISTING

- - We do not intend to list the Notes on any securities exchange or quotation
  system.

<TABLE>
<CAPTION>
                                 INITIAL PUBLIC         UNDERWRITING DISCOUNT          PROCEEDS TO US
                                 OFFERING PRICE            AND COMMISSIONS            BEFORE EXPENSES
                                 --------------         ---------------------         ---------------
<S>                         <C>                        <C>                        <C>
Per Note..................
Total.....................
</TABLE>

    BEFORE MAKING ANY INVESTMENT IN OUR SECURITIES, YOU SHOULD READ THE BASE
 PROSPECTUS TO WHICH THIS PROSPECTUS SUPPLEMENT RELATES AND CAREFULLY CONSIDER
  CERTAIN RISKS DESCRIBED IN THE RISK FACTORS BEGINNING ON PAGE 4 OF THE BASE
                                  PROSPECTUS.

     The Notes are not savings accounts, deposits or other obligations of any
bank and are not insured by the Federal Deposit Insurance Corporation or any
other governmental agency.

     NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES
COMMISSION HAS APPROVED OR DISAPPROVED OF THESE SECURITIES OR DETERMINED THAT
THIS PROSPECTUS SUPPLEMENT OR THE ATTACHED PROSPECTUS IS TRUTHFUL OR COMPLETE.
ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.

                          Joint Book Running Managers

BANC OF AMERICA SECURITIES LLC                             CHASE SECURITIES INC.
                             ---------------------
                                 June   , 1999

THE INFORMATION CONTAINED IN THIS PROSPECTUS SUPPLEMENT IS NOT COMPLETE AND MAY
BE CHANGED. WE ARE NOT USING THIS PROSPECTUS SUPPLEMENT AND THE ACCOMPANYING
PROSPECTUS TO OFFER TO SELL THESE SECURITIES OR TO SOLICIT OFFERS TO BUY THESE
SECURITIES IN ANY PLACE WHERE THE OFFER OR SALE IS NOT PERMITTED.
<PAGE>   2

     In making your investment decision, you should rely only on the information
contained or incorporated by reference into this prospectus supplement and the
accompanying prospectus. We have not authorized anyone to provide you with any
other information. If you receive any unauthorized information, you should not
rely on it.

     We are offering to sell the Notes only in places where sales are permitted.

     You should not assume that the information contained or incorporated by
reference in this prospectus supplement or the accompanying prospectus is
accurate as of any date other than the date indicated in the respective
document.

     In this prospectus supplement and the accompanying prospectus, the
"Company," "we," "us" and "our" refer to BOK FINANCIAL CORPORATION.

                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
PROSPECTUS SUPPLEMENT                   PAGE
- ---------------------                   ----
<S>                                     <C>
The Company...........................   S-3
Recent Developments...................   S-5
Selected Consolidated Financial and
  Operating Data......................   S-7
Use of Proceeds.......................   S-9
Capitalization........................   S-9
Ratio of Earnings to Fixed Charges....   S-9
Description of Notes..................  S-10
Underwriting..........................  S-11
Where You Can Find More Information...  S-12
Validity of Notes.....................  S-13
</TABLE>

<TABLE>
<CAPTION>
PROSPECTUS                              PAGE
- ----------                              ----
<S>                                     <C>
About this Prospectus.................     1
Where You Can Find More Information...     1
Summary Information Respecting BOK....     2
Risk Factors..........................     3
Description of Senior Debt
  Securities..........................     5
Global Securities.....................    11
Use of Proceeds.......................    13
Plan of Distribution..................    13
Ratio of Earnings to Fixed Charges....    14
Validity of the Senior Debt
  Securities..........................    14
Experts...............................    14
</TABLE>

                        ABOUT THIS PROSPECTUS SUPPLEMENT

     We provide information to you about the Notes in two separate documents:
(a) the accompanying prospectus, which provides general information, some of
which may not apply to the Notes and (b) this prospectus supplement, which
describes the specific terms of the Notes. Generally, when we refer to this
"prospectus," we are referring to both documents combined.

     IF INFORMATION IN THIS PROSPECTUS SUPPLEMENT IS INCONSISTENT WITH THE
PROSPECTUS, YOU SHOULD RELY ON THIS PROSPECTUS SUPPLEMENT.

     It is important for you to read and consider all information contained in
this prospectus supplement and the accompanying prospectus in making your
investment decision. You should also read and consider the information in the
documents to which we have referred you in "Where You Can Find More Information"
on page S-12.

     If we use a capitalized term in this prospectus supplement and do not
define the term in this document, the capitalized term is defined in the
prospectus.

               SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

     This prospectus and the information incorporated by reference includes
forward-looking statements within the meaning of Section 27A of the Securities
Act of 1933 and Section 21E of the Securities Exchange Act of 1934. Some of the
forward-looking statements can be identified by the use of forward-looking words
such as "believes," "contemplates," "expects," "may," "will," "should," "seeks,"
"approximately," "intends," "plans," "estimates," or "anticipates" or the
negative of those words or other comparable terminology. Forward-looking
statements involve inherent risks and uncertainties. A number of

                                       S-2
<PAGE>   3

important factors could cause actual results to differ materially from those in
the forward-looking statements. These factors include fluctuations in market
activity, interest rates, inflation, government regulations, and economic
conditions and competition in the geographic and business areas in which we
conduct our operations. For a discussion of factors that could cause actual
results to differ, please see the discussion under "Risk Factors" contained on
page 4 of the base prospectus and in other information contained in our publicly
available SEC filings.

                                  THE COMPANY

     We are a bank holding company, incorporated in Oklahoma on October 24,
1990, whose activities are limited by the Bank Holding Company Act of 1956, as
amended, to banking, certain bank-related services and activities, and managing
or controlling banks. Our banking and bank-related activities are primarily
performed through Bank of Oklahoma, N.A., Bank of Texas, N.A., Bank of
Albuquerque N.A., and Bank of Arkansas, N.A. Our other significant operating
subsidiaries include BOSC, Inc., which is a full-service securities firm with
specialized expertise in public and municipal finance, asset-backed securities
and private placements, and BOK Capital Services Corporation, which provides
leasing and mezzanine financing. As of December 31, 1998, the Company and its
subsidiaries had 2,758 full-time equivalent employees. Our common stock is
listed on the Nasdaq National Market under the symbol "BOKF."

     We are the largest bank holding company headquartered in the state of
Oklahoma. We conduct business primarily in Oklahoma and selected markets in
neighboring states. We provide a broad array of financial products and services
to major corporations, middle-market companies, small businesses, retail
customers and other entities, which include:

     - corporate, small business and consumer lending;

     - deposit taking;

     - corporate treasury services and cash management;

     - mortgage lending and servicing;

     - trust and asset management services;

     - automated teller machine network services; and

     - capital markets services.

     We have the number one deposit market share in Oklahoma and a leading
market position in nine of the 11 Oklahoma counties in which we operate. As of
March 31, 1999, approximately 73% of our assets were managed in Tulsa and in
Oklahoma City and 11% in the Dallas/Fort Worth area, with additional assets
managed in other Oklahoma markets, as well as Fayetteville, Arkansas and
Albuquerque, New Mexico. We are the largest originator of mortgage loans in
Oklahoma, serve as the state's leading fiduciary and own the state's largest
ATM/EFT network and supermarket banking network.

     As of and for the three months ended March 31, 1999, we had:

     - assets of $7.0 billion;

     - loans of $3.6 billion;

     - deposits of $4.3 billion;

     - shareholders' equity of $519 million; and

     - net income of $19.8 million.

BUSINESS SEGMENTS

     Our operations are divided into four primary segments and Other Financial
Services. As a percentage of our 1998 total revenue, Corporate Banking
represented 29%, Consumer Banking represented 20%, Mortgage Banking represented
14% and Trust Services represented 13%. Other Financial Services

                                       S-3
<PAGE>   4

represented 17% and other revenue, primarily from asset and liability
management, represented the remaining 7%.

  Corporate Banking Division:

     - offers commercial and industrial loans, real estate financing, commercial
       mortgage loans, specialized industry loans, trade finance and letters of
       credit, lease financing, selected capital markets products and highly
       specialized treasury and cash management products;

     - is the market leader in Oklahoma and has a significant presence in its
       largest counties; and

     - had average loans of $2.0 billion and average deposits of $536 million in
       1998.

  Consumer Banking Division:

     - provides a full line of deposit, loan and fee-based banking products to
       retail and small business customers;

     - is the deposit market share leader in Oklahoma and, through our
       subsidiaries, has the fourth largest branch network in Albuquerque and
       the fifth largest in the State of New Mexico; and

     - had average loans of $320 million and average deposits of $1.7 billion in
       1998.

  Mortgage Banking Division:

     - originates, purchases, sells and services individual residential mortgage
       loans;

     - is the largest mortgage originator in Oklahoma;

     - services a $6.7 billion mortgage portfolio as of December 31, 1998; and

     - had mortgage loan originations of $850 million in 1998.

  Trust Services Division:

     - provides institutional, investment and retirement products, including
       401(k) plans, mutual fund products, cash management and trust services to
       affluent individuals, businesses, non-profit organizations and government
       entities; and

     - is currently responsible for more than $14 billion in assets.

  Other Financial Services:

     Other Financial Services comprises:

     - TransFund. This division provides merchants and financial institutions
       with a full line of ATM, debit/credit card and merchant payment
       processing products.

     - BOSC, Inc. This subsidiary specializes in the execution of securities
       transactions as well as public and municipal finance activities and is
       responsible for retail sales and brokerage activity.

     - Bank of Texas. This subsidiary provides corporate and consumer banking
       and other financial services in the Dallas/Fort Worth metropolitan area,
       focusing on middle-market banking.

     - Bank of Albuquerque. This subsidiary serves as the hub for expanding our
       consumer and commercial banking and fiduciary service operations in New
       Mexico.

     - Bank of Arkansas. This subsidiary provides corporate and consumer
       banking, public finance, capital markets services and other financial
       services in northwest Arkansas.

                                       S-4
<PAGE>   5

     As a percentage of our 1998 revenue, TransFund represented 6%, BOSC, Inc.
represented 3%, Bank of Texas represented 7% and the Banks of Arkansas and
Albuquerque (which represented only 27 days of Bank of Albuquerque operations)
together represented less than 2%.

                              RECENT DEVELOPMENTS

FIRST QUARTER RESULTS

     Net income for the three months ended March 31, 1999 was $19.8 million, or
$0.38 per share, an increase of 22% over the corresponding period of 1998.
Earnings per share amounts are reported on a diluted basis and have been
adjusted for a two-for-one stock split in the form of a 100% stock dividend paid
on February 22, 1999. The Company's loan balances were $3.6 billion at March 31,
1999, an increase of 21.5% excluding the effect of the Bank of Albuquerque, N.A.
acquisition which was consummated on December 4, 1998. Fee-based revenue for the
first quarter of 1999 increased 22%, representing 46% of total revenue. The
sharpest gains were seen in brokerage and trading revenue at 39%, to $4.3
million, and transaction card revenue at 36%, to $7.6 million. Mortgage revenue
declined slightly due to a lower level of servicing revenue.

  Net Interest Revenue

     Net interest revenue on a tax-equivalent basis was $52.2 million for the
first quarter of 1999 compared to $44.4 million for the first quarter of 1998,
an increase of 18%. Average earning assets increased by $1.0 billion, including
increases in average loans of $701 million and average securities of $306
million. Interest-bearing liabilities increased $950 million, primarily due to
increases in borrowed funds of $663 million.

     Net interest margin, the ratio of net interest revenue to average earning
assets, was 3.57% for the first quarter of 1999 compared to 3.65% for the first
quarter of 1998 and 3.72% for the fourth quarter of 1998. The primary reason for
the decrease in the net interest margin was the securitization sale of
approximately $100 million of automobile loans in the first quarter of 1999.
These loans had an average yield of 9.23%, which is greater than the overall
yield on average earning assets. Additionally, the sale was structured so that
we were required to carry a non-earning asset on our balance sheet for 36 days
during the quarter. This caused approximately 14 basis points of the decrease in
the net interest margin for the quarter.

  Other Operating Revenue

     Other operating revenue for the first quarter of 1999 increased $6.1
million or 15% compared to the same quarter of 1998. Total fees and commissions,
which are included in other operating revenue, increased $8.0 million or 22%.
All categories of fee income, except mortgage banking revenue, showed increases
over the first quarter of 1998. Most notably, other revenue increased $2.3
million due primarily to a $1.6 million increase in underwriting and advisory
fees for BOSC, Inc. The decrease in mortgage banking revenue was due to lower
servicing revenue. Servicing revenue was $7.9 million and $8.5 million,
respectively, for the first quarters of 1999 and 1998. Mortgage loan refinancing
activity reduced the amount of loans that we serviced and the servicing revenue.
Gain on the sale of other assets included $752 thousand from the sale of an
interest in a local bank.

  Other Operating Expenses

     Operating expenses for the first quarter of 1999 increased $6.4 million or
11% compared to the first quarter of 1998. The first quarter of 1999 includes
operating expenses of $6.1 million for the Bank of Albuquerque, which did not
exist in the first quarter of 1998. The first quarter of 1998 included charges
of $2.3 million for the cost of stock contributed to the BOk Charitable
Foundation and $3.0 million for a provision for the possible impairment of
mortgage servicing rights. The remaining discussion excludes these charges for
both 1999 and 1998 to improve comparability. Personnel costs increased $4.3
million due to increased staffing, normal compensation increases and increased
incentive compensation. Staffing on a full-
                                       S-5
<PAGE>   6

time equivalent ("FTE") basis increased by 211 employees while average
compensation per FTE increased by 3.9%. Incentive compensation, which varies
directly with revenue increased $909 thousand to $3.6 million for the quarter.
The increase in incentive compensation was due to growth in revenue over
pre-determined targets and growth in the number of business units covered by
incentive plans. Occupancy, equipment and data processing costs increased $2.7
million or 29%, which included increases of $922 thousand in net occupancy costs
and $1.4 million in data processing costs. The increase in net occupancy costs
was due primarily to a decrease in rental income on bank premises of $574
thousand. A significant portion of our data processing is outsourced to third
parties. Therefore, data processing costs are directly related to the volume of
transactions processed.

  Summary of Loan Loss Experience

     The reserve for loans losses, which is available to absorb losses inherent
in the loan portfolio, totaled $68 million at March 31, 1999 and $65 million at
December 31, 1998. This represents 1.94% and 1.88% of total loans, excluding
loans held for sale, at March 31, 1999 and December 31, 1998, respectively.

     A provision for loan losses is charged against earnings in amounts
necessary to maintain an adequate allowance for loan losses. These provisions
were $3.4 million for the first quarter of 1999 compared to $2.5 million for the
first quarter of 1998.

  Non-Performing Assets

     Non-performing assets were $20 million at March 31, 1999 and $18 million at
December 31, 1998. Non-performing loans include non-accrual loans and
renegotiated loans.

ACQUISITIONS

     We recently acquired three banks located in the Dallas/Fort Worth area for
cash in the amount of approximately $76 million and we plan to acquire an
additional bank in Oklahoma for approximately 2,371,829 shares of our common
stock on June 30, 1999.

<TABLE>
<CAPTION>
                                                                                      AS OF DECEMBER 31, 1998
                                                                                     --------------------------
CLOSING                                                                              TOTAL    TOTAL     TOTAL
DATE                              NAME                    PLACE OF OPERATION         ASSETS   LOANS    DEPOSITS
- -------                           ----                    ------------------         ------   ------   --------
                                                                                           (IN MILLIONS)
<S>                    <C>                          <C>                              <C>      <C>      <C>
6/30/99..............  First National Bank &        Muskogee, Oklahoma               $250.2   $94.0     $228.0
                       Trust Company of Muskogee
5/14/99..............  Canyon Creek National Bank   Richardson and McKinney, Texas     99.3    56.4       85.1
6/04/99..............  Mid-Cities National Bank     Tarrant County, Texas              73.4    40.8       67.1
6/16/99..............  Swiss Avenue State Bank      Dallas, Texas                     223.6    49.4      175.6
</TABLE>

     The three acquisitions in the Dallas/Fort Worth metropolitan area are
expected to increase our total assets and deposits in the area by over $396
million and $328 million respectively, giving us an approximate 2% share in this
$41 billion deposit market. The Board of Governors of the Federal Reserve System
approved the acquisition of First Bancshares of Muskogee on May 24, 1999. The
closing is currently scheduled for June 30, 1999.

EQUITY OFFERING

     We are contemplating offering approximately 6 million shares of common
stock in 1999. It is currently contemplated that approximately 4 million shares
will be a secondary offering by current shareholders and 2 million shares will
be newly issued. We cannot guarantee that this offering will occur as
contemplated, if at all.

     A registration statement relating to these securities is being prepared but
has not yet been filed with the Securities and Exchange Commission. These
securities will be offered only by means of a prospectus and may not be sold nor
may offers to buy be accepted prior to the time the registration statement
becomes effective. This prospectus supplement shall not constitute an offer to
sell or the solicitation of an offer to buy nor shall there be any sale of those
securities in any state in which such offer, solicitation or sale would be
unlawful prior to registration or qualification under the securities laws of any
such state.

                                       S-6
<PAGE>   7

               SELECTED CONSOLIDATED FINANCIAL AND OPERATING DATA

     The following table sets forth selected consolidated financial data for the
Company as of the dates or for the periods indicated. This information should be
read in conjunction with, and is qualified in its entirety by reference to, the
detailed information and financial statements included in the documents
incorporated herein by reference. See "Where You Can Find More Information" on
page S-12.

     You should read the following information with the data in the table on the
next page:

     - Per share data has been restated to reflect the two-for-one stock split
       in the form of a 100% stock dividend paid on February 22, 1999 and a 3%
       stock dividend paid on November 25, 1998.

     - We have presented net interest income and income before income taxes on a
       taxable-equivalent basis using a combined federal and state statutory tax
       rate of 38.9%.

     - Other operating expense includes merger and integration expense, which
       was $98,000 for 1996, $112,000 for 1997 and $2.0 million for 1998.

     - Tangible return on average shareholders' equity is net income plus
       intangible amortization net of income taxes divided by average
       shareholders' equity.

     - The efficiency ratio is noninterest expense not including foreclosed
       asset expense or income, as a percentage of the sum of net interest
       income (on a taxable-equivalent basis) and noninterest income.

     - The Tier 1 leverage ratio is computed by dividing Tier 1 capital, which
       is total shareholders' equity less net unrealized gains and losses on
       securities available for sale and intangible assets, by average tangible
       assets.

     - The Tier 1 capital ratio is computed by dividing Tier 1 capital by
       risk-weighted period-end assets. Risk-weighted period-end assets is the
       balance of the assets at risk less the portion of the allowance for
       credit losses which exceeds 1.25% of the balance of the assets at risk.
       The balance of the assets at risk is calculated by applying risk-weighted
       percentages per regulatory guidelines to total assets and off-balance
       sheet items.

     - The tangible shareholders' equity ratio is tangible shareholders' equity
       divided by tangible assets.

     - The total capital ratio is total risk-based capital divided by total
       risk-adjusted assets.

     - The reserve for loan losses to loans is computed by dividing the reserve
       for loan losses by total loans, excluding residential mortgage loans held
       for sale which are carried at the lower of aggregate cost or market
       value.

                                       S-7
<PAGE>   8

<TABLE>
<CAPTION>
                                                                                                       THREE MONTHS
                                                                                                           ENDED
                                                    YEAR ENDED DECEMBER 31,                              MARCH 31,
                                 --------------------------------------------------------------   -----------------------
                                    1994         1995         1996         1997         1998         1999         1998
                                 ----------   ----------   ----------   ----------   ----------   ----------   ----------
                                                 (DOLLARS IN THOUSANDS, EXCEPT PER SHARE AND RATIO DATA)
<S>                              <C>          <C>          <C>          <C>          <C>          <C>          <C>
RESULTS OF OPERATIONS:
Taxable-equivalent interest
  revenue......................  $  229,175   $  282,479   $  298,897   $  354,115   $  395,880   $  108,841   $   95,074
Interest expense...............     104,055      160,177      163,093      188,948      204,335       56,610       50,708
                                 ----------   ----------   ----------   ----------   ----------   ----------   ----------
Taxable-equivalent net interest
  revenue......................     125,120      122,302      135,804      165,167      191,545       52,231       44,366
Provision for loan losses......         195          231        4,267        9,026       14,451        3,370        2,470
Other operating revenue........      74,364       91,146      105,312      129,699      172,819       46,865       40,787
Other operating expense........     133,475      142,206      159,028      195,166      228,665       63,593       57,193
                                 ----------   ----------   ----------   ----------   ----------   ----------   ----------
Income before income taxes.....      65,814       71,011       77,821       90,674      121,258       32,133       25,490
Income tax expense.............      20,749       21,806       23,694       26,049       46,542       12,316        9,177
                                 ----------   ----------   ----------   ----------   ----------   ----------   ----------
Net income.....................  $   45,065   $   49,205   $   54,127   $   64,625   $   74,716   $   19,817   $   16,313
                                 ==========   ==========   ==========   ==========   ==========   ==========   ==========
BALANCE SHEET DATA (END OF
  PERIOD):
Assets.........................  $3,927,276   $4,244,118   $4,620,700   $5,399,642   $6,809,348   $7,044,000   $5,632,667
Loans..........................   1,844,053    2,194,368    2,394,580    2,765,093    3,551,941    3,591,398    2,836,296
Intangible assets..............      43,846       37,134       28,276       67,796       95,935       93,933       65,494
Non-performing assets..........      24,214       32,687       23,411       24,232       17,716       19,827       24,181
Deposits.......................   2,629,574    2,937,709    3,256,755    3,728,079    4,379,230    4,342,935    4,019,374
Subordinated debenture.........      23,000           --           --      148,356      146,921      148,504      148,388
Shareholders' equity...........     236,902      301,565      359,966      435,477      505,114      519,207      448,635
PROFITABILITY RATIOS:
Return on average assets.......        1.26%        1.22%        1.26%        1.27%        1.31%        1.19%        1.19%
Tangible return on average
  assets.......................        1.38         1.34         1.43         1.42         1.46         1.36         1.34
Return on average shareholders'
  equity.......................       19.92        18.07        16.80        16.41        15.99        15.75        14.89
Tangible return on average
  shareholders' equity.........       21.90        19.85        19.03        18.42        17.79        18.05        16.78
Net interest margin............        3.94         3.39         3.54         3.66         3.72         3.57         3.65
Efficiency ratio...............       69.20        68.07        67.84        67.49        62.89        65.48        67.23
RISK-BASED CAPITAL RATIOS:
Tier 1 capital ratio...........        9.14%        9.91%       10.49%        9.39%        7.80%        8.06%        9.47%
Total capital ratio............       11.19        11.17        11.74        14.54        11.96        12.15        14.47
Leverage ratio.................        5.64         6.55         7.46         6.81         6.57         6.31         6.81
CREDIT QUALITY RATIOS:
Reserve for loan losses to non-
  performing loans.............      190.27%      130.73%      239.70%      279.86%      495.05%      452.85%      291.46%
Reserve for loan losses to
  loans........................        2.12         1.80         1.96         1.98         1.88         1.94         2.02
Provision for loan losses to
  average total loans..........        0.01         0.01         0.19         0.35         0.50         0.39         0.36
Net loans charged off to
  average total loans..........        0.01         0.01        (0.12)        0.14         0.09         0.04         0.10
Non-performing assets to total
  loans and foreclosed
  assets.......................        1.31         1.49         0.98         0.87         0.50         0.55         0.85
Non-performing assets to total
  assets.......................        0.62         0.77         0.51         0.45         0.26         0.28         0.43
</TABLE>

                                       S-8
<PAGE>   9

                                USE OF PROCEEDS

     We intend to use the proceeds of the offering to repay $25 million of
indebtedness to NationsBank, N.A., a subsidiary of Bank of America Corporation,
and $25 million of indebtedness to Chase Bank of Texas, N.A. under credit
agreements maturing September 30, 1999. Such indebtedness was incurred to
acquire 17 branches and $475 million in deposits which now constitutes our Bank
of Albuquerque, NA subsidiary. In addition, we intend that $7.5 million will be
used to reduce borrowings from Wachovia Bank, N.A. under a credit facility
maturing September 30, 1999. Further, we intend to use $15 million to repay
other borrowings from NationsBank, N.A. and Chase Bank of Texas, N.A. ($7.5
million each), also maturing September 30, 1999, related to the three
acquisitions in the Dallas/Ft. Worth market in 1999. All borrowings are at LIBOR
+ 70 bp. The remaining proceeds, approximately $26 million, will be used for
general corporate purposes, possibly including current and future acquisitions,
if any. NationsBank, N.A. and Chase Bank of Texas, N.A. are affiliates of the
underwriters.

                                 CAPITALIZATION

     The following table presents our short-term debt and total capitalization
on a consolidated basis at March 31, 1999, and as adjusted to reflect the
issuance of the Notes and the repayment of indebtedness. This table should be
read in conjunction with our consolidated financial statements and the notes
incorporated by reference in the accompanying prospectus.

<TABLE>
<CAPTION>
                                                                    MARCH 31, 1999
                                                              ---------------------------
                                                                ACTUAL        AS ADJUSTED
                                                              ----------      -----------
                                                                (DOLLARS IN THOUSANDS)
<S>                                                           <C>             <C>
Short-term debt:
  Funds purchased and repurchase agreements.................  $1,050,955      $1,050,955
  Other borrowings..........................................     893,819         821,319
                                                              ----------      ----------
       Total short-term debt................................  $1,944,774      $1,872,274
                                                              ==========      ==========
Long-term debt:
Senior debt.................................................  $       --      $  100,000
Subordinated debentures.....................................     148,504         148,504
                                                              ----------      ----------
       Total long-term debt.................................     148,504         248,504
       Total shareholders' equity...........................     519,207         519,207
                                                              ----------      ----------
          Total capitalization..............................  $  667,711      $  767,711
                                                              ==========      ==========
</TABLE>

                       RATIO OF EARNINGS TO FIXED CHARGES

<TABLE>
<CAPTION>
                                                                                  THREE MONTHS
                                                                                      ENDED
                                             YEAR ENDED DECEMBER 31,                MARCH 31,
                                     ----------------------------------------     -------------
                                     1994     1995     1996     1997     1998     1999     1998
                                     ----     ----     ----     ----     ----     ----     ----
<S>                                  <C>      <C>      <C>      <C>      <C>      <C>      <C>
Excluding Interest on Deposits.....  2.81     2.02     2.54     2.21     2.51     2.24     2.34
Including Interest on Deposits.....  1.57     1.40     1.43     1.43     1.55     1.53     1.46
</TABLE>

     These computations include BOK Financial Corporation and its subsidiaries
and serve to update the "Ratio of Earnings to Fixed Charges" in the prospectus.
For these ratios, "earnings" are determined by adding "fixed charges" to income
from continuing operations before income taxes. "Fixed charges" consist of
interest on all debt and amortization of premiums or discounts associated with
debt.

                                       S-9
<PAGE>   10

                              DESCRIPTION OF NOTES

     The following description of the particular terms of the Notes supplements
the description of the general terms and provisions of the Senior Debt
Securities set forth in the accompanying prospectus under the heading
"Description of Senior Debt Securities". The following description does not
purport to be complete and is qualified in its entirety by reference to the
accompanying prospectus and the provisions of the Senior Indenture (as defined
below). Capitalized terms used but not defined in this document have the
meanings assigned to such terms in the accompanying prospectus or in the Senior
Indenture.

GENERAL

     The Notes offered hereby constitute a series of Senior Debt Securities
described in the accompanying prospectus to be issued under the Indenture, dated
as of                , 1999 (the "Senior Indenture"), between the Company and
The Chase Manhattan Bank, as Trustee (the "Senior Trustee"). The Notes will be
limited to $100,000,000 aggregate principal amount, will be direct, unsecured
obligations of the Company and will mature on                , 200 .

     The Notes will bear interest at the rate per annum shown on the cover page
of this prospectus supplement, payable semi-annually on each                and
               , beginning                , 1999, to the persons in whose names
the Notes are registered at the close of business on the                or
               , as the case may be, next preceding such                and
               .

     The Notes do not provide for any sinking fund and may not be redeemed prior
to maturity.

BOOK ENTRY FORM

     The Notes will be issued in the form of one or more fully registered
permanent Global Securities registered in the name of DTC or its nominee as
described under "Description of Senior Debt Securities -- Global Securities" in
the accompanying prospectus.

DEFEASANCE AND DISCHARGE

     The defeasance provisions of the Senior Indenture described under
"Description of Debt Securities -- Defeasance and Discharge" in the accompanying
prospectus will apply to the Notes.

SAME-DAY SETTLEMENT AND PAYMENT

     Settlement by purchasers of the Notes will be made in immediately available
funds. All payments by the Company to the Depositary of principal and interest
will be made in immediately available funds.

     So long as any Notes are represented by Global Securities registered in the
name of the Depositary or its nominee, such Notes will trade in the Depositary's
Same-day Funds Settlement System and secondary market trading in such Notes will
therefore be required by the Depositary to settle in immediately available
funds. No assurance can be given as to the effect, if any, of settlement in
immediately available funds on trading activity in the Notes.

TRUSTEE

     The Chase Manhattan Bank will serve as the Senior Trustee with respect to
the Notes.

                                      S-10
<PAGE>   11

                                  UNDERWRITING

     We and the underwriters named below (the "Underwriters") have entered into
an underwriting agreement relating to the offering and sale of the Notes (the
"Underwriting Agreement"). In the Underwriting Agreement, we have agreed to sell
to each Underwriter, and each Underwriter has agreed to purchase from us, the
principal amount of Notes that appears opposite its name in the table below:

<TABLE>
<CAPTION>
UNDERWRITER                                                    PRINCIPAL AMOUNT
- -----------                                                    ----------------
<S>                                                            <C>
Banc of America Securities LLC..............................
Chase Securities Inc........................................
                                                                 ------------
          Total.............................................     $100,000,000
                                                                 ============
</TABLE>

     The obligations of the Underwriters under the Underwriting Agreement,
including their agreement to purchase Notes from us, are several and not joint.
Those obligations are also subject to certain conditions in the Underwriting
Agreement being satisfied. The Underwriters have agreed to purchase all of the
Notes if any of them are purchased.

     The Underwriters have advised us that they propose to offer the Notes to
the public at the public offering price that appears on the cover page of this
prospectus supplement. The Underwriters may offer the Notes to selected dealers
at the public offering price minus a selling concession of up to   % of the
principal amount. In addition, the Underwriters may allow, and those selected
dealers may reallow, a selling concession of up to   % of the principal amount
to certain other dealers. After the initial public offering, the Underwriters
may change the public offering price and any other selling terms.

     In the Underwriting Agreement, we have agreed that:

     - we will pay our expenses related to the Offering, which we estimate will
       be $          ; and

     - we will indemnify the Underwriters against certain liabilities, including
       liabilities under the Securities Act of 1933, as amended.

     The Notes are a new issue of securities, and there is currently no
established trading market for the Notes. In addition, we do not intend to apply
for the Notes to be listed on any securities exchange or to arrange for the
Notes to be quoted on any quotation system. The Underwriters have advised us
that they intend to make a market in the Notes, but they are not obligated to do
so and may discontinue any market making in the Notes at any time in their sole
discretion. Accordingly, we cannot assure you that a liquid trading market will
develop for the Notes, that you will be able to sell your Notes at a particular
time or that the prices that you receive when you sell will be favorable.

     In connection with the offering of the Notes, the Underwriters may engage
in overallotment, stabilizing transactions and syndicate covering transactions
in accordance with Regulation M under the Securities Exchange Act of 1934, as
amended. Overallotment involves sales in excess of the offering size, which
creates a short position for the Underwriters. Stabilizing transactions involve
bids to purchase the Notes in the open market for the purpose of pegging, fixing
or maintaining the price of the Notes. Syndicate covering transactions involve
purchases of the Notes in the open market after the distribution has been
completed in order to cover short positions. Stabilizing transactions and
syndicate covering transactions may cause the price of the Notes to be higher
than it would otherwise be in the absence of those transactions. If the
Underwriters engage in stabilizing or syndicate covering transactions, they may
discontinue them at any time.

     In the ordinary course of their respective businesses, the Underwriters and
their affiliates have engaged and may in the future engage in general financing
and banking transactions with the Company and its affiliates. The Chase
Manhattan Bank, the Senior Trustee, is an affiliate of Chase Securities Inc. In
addition affiliates of Banc of America Securities LLC and Chase Securities Inc.
are lenders to the Company and will receive a portion of the amounts repaid by
the Company under certain lending facilities with the net proceeds of the
offering. See "Use of Proceeds." Because affiliates of the Underwriters will
receive more than 10% of the net proceeds of the offering, this offering is
being conducted pursuant to Rule 2710(c)(8) of the Conduct Rules of the National
Association of Securities Dealers, Inc.

                                      S-11
<PAGE>   12

                      WHERE YOU CAN FIND MORE INFORMATION

     This prospectus supplement and the prospectus relate to a "shelf"
registration statement we have filed with the SEC under the Securities Act of
1933, as amended, with respect to the Notes being offered by this prospectus
(the "Registration Statement"). The Registration Statement, including the
attached exhibits and schedules, contains additional relevant information about
the Company and the securities described in the prospectus and this prospectus
supplement. The SEC's rules and regulations allow us to omit certain information
included in the Registration Statement from the prospectus and this prospectus
supplement. The Registration Statement may be inspected by anyone without charge
at the SEC's principal office at 450 Fifth Street, N.W., Washington, D.C. 20549.

     In addition, we file reports, proxy statements and other information with
the SEC under the Securities Exchange Act of 1934. You may read and copy this
information at the following SEC locations:

<TABLE>
<S>                                    <C>
Public Reference Room                  Fort Worth Regional Office
450 Fifth Street, N.W.                 503 U.S. Courthouse
Room 1024                              10th and Lamar Streets
Washington, D.C. 2054                  Fort Worth, Texas 76102
</TABLE>

     You may also obtain copies of this information by mail from the SEC's
Public Reference Room, 450 Fifth Street, N.W., Room 1024, Washington, D.C.
20549, at rates determined by the SEC. You may obtain information on the
operation of the Public Reference Room by calling the SEC at 1-800-732-0330.

     You can also inspect reports, proxy statements and other information that
we have filed electronically with the SEC at the SEC's web site at
http://www.sec.gov. These documents can also be inspected at the offices of the
National Association of Security Dealers, Inc., Report Section, 1735 K Street
N.W. Washington, D.C. 20006 or at Listing Company Information, NASDAQ Stock
Exchange, 9801 Washington Blvd., Gaithersburg, Maryland 20878.

     The SEC allows us to "incorporate by reference" information into the
prospectus and this prospectus supplement. This means that we can disclose
important information to you by referring you to another document filed
separately with the SEC. The information incorporated by reference is considered
to be a part of the prospectus and this prospectus supplement, except for any
information that is superseded by information that is included directly in this
document.

     This prospectus supplement incorporates by reference the documents listed
below that we have previously filed with the SEC. They contain important
information about us and our financial condition.

<TABLE>
<CAPTION>
COMPANY FILINGS                                         PERIOD
- ---------------                                         ------
<S>                                        <C>
Annual Report on Form 10-K...............  Year ended December 31, 1998
Quarterly Report on Form 10-Q............  Three Months Ended March 31, 1999
</TABLE>

     We also incorporate by reference additional documents that we may file with
the SEC after the date of this prospectus supplement. These documents include
periodic reports, such as Annual Reports on Form 10-K, Quarterly Reports on Form
10-Q and Current Reports on Form 8-K.

     Documents incorporated by reference are available from us without charge,
excluding any exhibits to those documents unless the exhibit is specifically
incorporated by reference as an exhibit in this prospectus supplement. You can
obtain documents incorporated by reference in this prospectus supplement by
requesting them in writing or by telephone from us at the following address:

                           BOK Financial Corporation
                             Bank of Oklahoma Tower
                         Boston Avenue at Second Street
                             Tulsa, Oklahoma 74172
                           Telephone: (918) 588-6752

                                      S-12
<PAGE>   13

                               VALIDITY OF NOTES

     The validity of the Notes will be passed upon for the Company by Frederic
Dorwart, Lawyers, Tulsa, Oklahoma, and for the Underwriters by Simpson Thacher &
Bartlett, New York, New York. Frederic Dorwart, Lawyers and certain of its
members are indebted to and have other banking and trust relationships with the
Company and/or its affiliates.

                                      S-13
<PAGE>   14

                                                                      PROSPECTUS

                           BOK FINANCIAL CORPORATION

                                     Issuer

                      $250,000,000 SENIOR DEBT SECURITIES

                           [BOK FINANCIAL CORP. LOGO]

  CONSIDER CAREFULLY THE RISK FACTORS BEGINNING ON PAGE 4 IN THIS PROSPECTUS.

     The Debt Securities will not be deposits and are not insured or guaranteed
by the Federal Deposit Insurance Corporation or any other governmental agency.

     The securities do not represent the obligations of any bank.

     This prospectus may be used to offer and sell any series of securities only
if accompanied by the prospectus supplement for that series.

     BOK Financial Corporation will:

     - issue one or more series of Senior Debt Securities

     - in the form of debentures, notes, or other unsecured evidences of
       indebtedness

     - in an amount not to exceed a total of $250,000,000

     - in definitive or global form

     A prospectus supplement will further define the Senior Debt Securities by
stating:

     - how the Senior Debt Securities will be sold

     - the initial offering price

     - the number of Senior Debt Securities being offered

     - the names of any underwriters and agents and their compensation

     - the net proceeds to BOK Financial of the sale

     - the use BOK Financial will make of the proceeds

     - the terms of the Senior Debt Securities including the interest rates,
       maturities, redemption rights, puts and other features

     NEITHER THE SECURITIES AND EXCHANGE COMMISSION NOR ANY STATE SECURITIES
COMMISSION HAS APPROVED OR DISAPPROVED OF THESE SECURITIES, OR PASSED UPON THE
ADEQUACY OR ACCURACY OF THE PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A
CRIMINAL OFFENSE.

     The common stock of BOK Financial is listed on the NASDAQ Stock Exchange
under the trading symbol "BOKF." BOK Financial does not plan to list the Senior
Debt Securities on NASDAQ or any other exchange.

                                October 12, 1998
<PAGE>   15

                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                              PAGE
                                                              ----
<S>                                                           <C>
About This Prospectus.......................................    1
Where You Can Find More Information.........................    1
Summary Information Respecting BOK Financial Corporation....    2
Risk Factors................................................    3
Description of Senior Debt Securities.......................    5
Global Securities...........................................   11
Use of Proceeds.............................................   13
Plan of Distribution........................................   13
Ratio of Earnings to Fixed Charges..........................   14
Validity of the Senior Debt Securities......................   14
Experts.....................................................   14
</TABLE>

                                        i
<PAGE>   16

                             ABOUT THIS PROSPECTUS

     This prospectus is part of a registration statement that we filed with the
SEC utilizing a "shelf" registration process. Under this shelf process, we may
sell any combination of the securities described in this prospectus in one or
more offerings up to a total dollar amount of $250,000,000. This prospectus
provides you with a general description of the securities we may offer. Each
time we sell securities, we will provide a prospectus supplement that will
contain specific information about the terms of that offering. The prospectus
supplement may also add, update or change information contained in this
prospectus. You should read both this prospectus and any prospectus supplement
together with additional information described under the heading "WHERE YOU CAN
FIND MORE INFORMATION."

     We are complying with the SEC's plain English program. This is an
initiative launched by the SEC to make prospectuses and other information more
understandable to the general investor. To see more detail, you should read the
exhibits filed with this registration statement.

                      WHERE YOU CAN FIND MORE INFORMATION

     We file annual, quarterly and special reports, proxy statements and other
information with the SEC. You may read and copy any document we file at the
SEC's public reference rooms at Room 1024, Judiciary Plaza, 450 Fifth Street,
N.W., Washington, D.C. 20549, and at the SEC's Fort Worth Regional Offices at
503 U.S. Courthouse, 10th and Lamar Streets, Forth Worth, Texas 76102 and at
Listing Company Information, NASDAQ Stock Exchange, 9801 Washington Blvd.,
Gaithersburg, Maryland 20878. You may send for a copy of such material for a fee
by writing the Securities and Exchange Commission Public Reference Section, Room
1024, 450 Fifth Street, N.W., Washington, D.C. 20549. Our SEC filings are also
available to the public over the Internet at the SEC's web site at
http://www.sec.gov. Please call the SEC at 1-800-SEC-0330 for further
information on the public reference rooms and Internet access.

     The SEC allows us to "incorporate by reference" the information we file
with them, which means that we can disclose important information to you by
referring you to those documents. The information incorporated by reference is
an important part of this prospectus, and information that we file later with
the SEC will automatically update and supersede this information. We incorporate
by reference the documents listed below and any future filings made with the SEC
under Sections 13(a), 13(c), 14, or 15(d) of the Securities Exchange Act of 1934
until we sell all of the securities.

     - Annual Report of the Company on Form 10-K for the fiscal year ended
       December 31, 1998; and

     - Quarterly Report on Form 10-Q for the fiscal quarter ended March 31,
       1999.

You may request a copy of these filings at no cost, by writing or telephoning us
at the following address:

        Chief Financial Officer
        BOK Financial Corporation
        Bank of Oklahoma Tower
        Tulsa, Oklahoma 74172
        (918) 588-6752
        [email protected]

     You should rely only on the information incorporated by reference or
provided in this prospectus or any prospectus supplement. We have not authorized
anyone else to provide you with different information. We are not making an
offer of these securities in any state where the offer is not permitted. You
should not assume that the information in this prospectus or any prospectus
supplement is accurate as of any date other than the date on the front of those
documents.

                                        1
<PAGE>   17

                              SUMMARY INFORMATION
                                   RESPECTING
                           BOK FINANCIAL CORPORATION

     - Our home office is Tulsa, Oklahoma

     - Our principal subsidiaries are Bank of Oklahoma N.A., Bank of Texas N.A.,
       Bank of Arkansas N.A., BOSC, Inc, BOK Capital Services Corporation, and
       Bank of Texas Trust Company, N.A.

     - We have a total of 2,758 employees

     - We offer commercial, consumer and correspondent banking services and
       investment and money market services

     - Our BOk Trust Division offers trust services, employee benefit services,
       investment advice, and asset management

     - Our BOk Mortgage Division originates and services home loan mortgages

     - Our BOSC subsidiary is a registered NASD broker-dealer with 91 sales
       representatives

     - The Leo Oppenheim Division of BOSC underwrites municipal revenue bonds,
       asset-backed securities, and commercial paper and has eight investment
       bankers and sales representatives

     - Approximately 95.5 percent of our earnings are derived from Bank of
       Oklahoma

     - Bank of Oklahoma is headquartered in Oklahoma, has 64 locations in
       Oklahoma, 2,442 employees, and approximately $3,470,843,000 in deposits.

     - Bank of Texas is headquartered in Dallas, Texas and has six locations,
       145 employees, and approximately $404,222,000 in deposits.

     - Bank of Arkansas is headquartered in Fayetteville, Arkansas and has three
       locations, 29 employees, and approximately $86,839,000 in deposits.

     - Bank of Albuquerque is headquartered in Albuquerque, New Mexico and has
       17 locations, 184 employees, and approximately $420,154,000 in deposits.

                                        2
<PAGE>   18

                                  RISK FACTORS

     THE SENIOR DEBT SECURITIES INVOLVE A RISK OF LOSS OF PRINCIPAL AND
INTEREST. YOU SHOULD CONSIDER THE FOLLOWING RISK FACTORS IN DECIDING WHETHER TO
PURCHASE THE SENIOR DEBT SECURITIES.

RISK OF COMPETITION

     - The banking industry is increasingly competitive

     - In particular, the Oklahoma banking industry is highly competitive and
       approximately 95.5% of our earnings are derived from Bank of Oklahoma

     - In 1997, NationsBank (now Bank America) and BancOne entered the Oklahoma
       market

     - We have to compete with numerous other small and large, local and
       national savings and loan associations, banks, credit unions, trust
       companies, broker-dealers, and underwriters

RISK OF SUPERVISION AND REGULATION

     - We and our subsidiaries are extensively regulated under both federal and
       state law, particularly the Bank Holding Company Act of 1956 and the
       National Bank Act

     - We are limited to the business of banking and related businesses, which
       prohibits us from expanding into certain types of businesses which could
       be profitable for us

     - Where we can do business and establish offices is regulated, which could
       decrease our ability to expand into new markets

     - The amount of deposits we can own in each state is regulated, which
       limits our potential growth

     - Our ability to make acquisitions and engage in new business may be
       limited by the performance of our obligations under the Community
       Reinvestment Act to provide services in traditionally underserved areas

     - We do not know the extent to which changes in the statutes and
       regulations under we operate may adversely affect our business and we do
       not have control over such changes

     - Those of our competitors which are not banks are subject to significantly
       less government regulation than we are, which may give them a competitive
       advantage in the marketplace

RISK OF REGULATORY LIMITATIONS ON PAYMENT OF DIVIDENDS

     - Our earnings will be the source of our ability to repay the Senior Debt
       Securities

     - Because we are a bank holding company, our earnings are principally
       derived from dividends from our banks

     - Regulations of the Comptroller of the Currency limit the ability of our
       banks to pay us dividends by requiring that a bank receive approval of
       the OCC before declaring a dividend if the amount of all dividends,
       including the proposed dividend, declared by a bank in any calendar year
       exceeds:

        (1) the total of the bank's net profits of that calendar year to date
            plus

        (2) retained net profits of the preceding two years minus

        (3) any required transfers to surplus or a fund for the retirement of
            preferred stock

RISK OF CAPITAL REQUIREMENTS

     - The Federal Deposit Insurance Improvement Act of 1991 established five
       capital rating tiers ranging from well capitalized to critically
       undercapitalized

                                        3
<PAGE>   19

     - We must maintain capital ratios above the well capitalized level if we
       want to experience significant growth and acquire other financial
       institutions and branches

     - Well capitalized means a minimum of 5% for Leverage Capital, 6% for Tier
       I Capital, and 10% for Total Capital

     - At March 31, 1999, our ratios were 6.31% for Leverage Capital, 8.06% for
       Tier I Capital, and 12.15% for Total Capital

     - At March 31, 1999, our subsidiary banks were also well above the required
       minimum leverage and risk-based ratios, but if we fall below these
       ratios, the growth potential of our business would be limited

RISK OF GOVERNMENT POLICIES AND ECONOMIC FACTORS

     Our business is highly sensitive to:

     - changes in legislation and the policies and examinations of the various
       regulatory authorities

     - the monetary policies implemented by the Federal Reserve Board, including
       the discount rate on bank borrowings and changes in reserve requirements
       which affects our ability to make loans and the interest rates we may
       charge

     - open market operations in U.S. Government securities

     - changes in prevailing interest rates because of the dependency of our
       banks on interest income and our substantial holdings of mortgage-backed
       securities and mortgage servicing rights, which are highly sensitive to
       changes in interest rates

     - poor economic conditions in Oklahoma and the other markets in the
       southwest region where we generate a substantial majority of our loans
       may cause us to incur losses associated with higher default rates and
       decreased collateral values in our loan portfolio

     - a significant portion of our total loans are to borrowers in cyclical
       industries (principally, commercial real estate, energy and agriculture),
       and, accordingly, downturns in one or more of these industries could have
       an adverse effect on our operations

     - in connection with our acquisitions of other bank and non-bank businesses
       and assets from time to time, we could face difficulties assimilating the
       personnel and operations of our acquired businesses, including the
       possible loss of key personnel, possible disruption of our on-going
       business, additional burdens on our management team, difficulties in
       maintaining uniform standards, controls, procedures and policies and
       possible unexpected increased costs related to these acquisitions.

     - We cannot predict the effect of such matters on our business and earnings

RISK OF LACK OF MARKETABILITY

     - We cannot guarantee a secondary market for our Senior Debt Securities or
       that holders who wish to sell their Senior Debt Securities prior to the
       stated maturity will be able to do so

     - We do not plan to list the Senior Debt Securities for trading on any
       exchange or other trading market

RISK OF YEAR 2000 PROBLEMS

     - We, and our service providers, are having to modify or replace
       significant portions of our and their computer software and hardware to
       ensure that our systems will function correctly in the Year 2000 and
       thereafter

     - We have made good progress and do not foresee any significant operational
       problems with our systems or those of our service providers; however, if
       we or our service providers do not timely
                                        4
<PAGE>   20

       complete the required modifications and replacements, we could experience
       a material adverse impact on our business and earnings

     - We may experience additional liquidity needs in connection with increased
       deposit withdrawals due to customer concerns over the Year 2000 issue.
       Although we have developed a contingency funding plan to prepare for this
       potential liquidity need, there can be no assurance that such steps will
       be adequate. As a result, significant customer withdrawal in advance or
       immediately following January 1, 2000 could have a material adverse
       effect on our results of operations or financial condition.

                     DESCRIPTION OF SENIOR DEBT SECURITIES

     This description of the Senior Debt Securities does not purport to be
complete and is subject to, and qualified in its entirety by reference to, the
indentures pursuant to which such Senior Debt Securities are issued, the forms
of which indentures are filed as exhibits to the registration statement of which
this prospectus is a part. Furthermore, the following summary description of the
indentures and the Senior Debt Securities relates to certain terms and
conditions applicable to the Senior Debt Securities generally. The particular
terms of any series of Senior Debt Securities will be described in the
applicable prospectus supplement. If so indicated in such prospectus supplement,
the terms of any such series may differ from the terms set forth below.

  General

     Senior Debt Securities are to be issued under an indenture (the
"Indenture") between BOK Financial Corporation and the trustee named in the
applicable prospectus supplement as the trustee therefor (the "Trustee"). The
form of Indenture is an exhibit to the registration statement of which this
prospectus is a part.

     The Senior Debt Securities will be direct, unsecured obligations of BOK
Financial Corporation. The Senior Debt Securities will not be deposits or other
obligations of a bank and will not be guaranteed or insured by the FDIC or any
other governmental agency.

     The Indenture does not limit the aggregate principal amount of Senior Debt
Securities or of any particular series of Senior Debt Securities that may be
issued thereunder and provide that Senior Debt Securities issued thereunder may
be issued from time to time in one or more series, in each case with the same or
various maturities, at par or at a discount. The Indenture does not limit the
amount of other debt that may be issued by BOK Financial Corporation and does
not contain financial or similar restrictive covenants. The Indenture does not
prohibit or limit the incurrence of additional senior indebtedness or other
financial obligations. The Indenture provides that there may be more than one
Trustee under such Indenture with respect to different series of Senior Debt
Securities.

     The Indenture does not contain any provision intended to provide protection
to holders of Senior Debt Securities against a sudden or dramatic decline in
credit quality of BOK Financial Corporation that could, for example, result from
a takeover, recapitalization, special dividend or other restructuring.

     The applicable prospectus supplement will describe the following terms of
the series of Senior Debt Securities in respect of which this prospectus is
being delivered:

          (1) the title of such Senior Debt Securities;

          (2) any limit upon the aggregate principal amount of such Senior Debt
     Securities and the percentage of such principal amount at which such Senior
     Debt Securities may be issued;

          (3) the date or dates on which the principal of such Senior Debt
     Securities is scheduled to become payable (the "Stated Maturity");

          (4) the rate or rates (which may be fixed or variable) per annum at
     which such Senior Debt Securities will bear interest, or the method of
     determining such rate or rates, if any, the date or dates
                                        5
<PAGE>   21

     from which any such interest will accrue, the dates on which any such
     interest will be payable (the "Interest Payment Dates"), the Regular Record
     Date (as defined in the Indenture) for the interest payable on any Interest
     Payment Date, and the person to whom principal of or premium, if any, or
     interest on any Senior Debt Security of such series will be payable, if
     other than the person in whose name such Senior Debt Security (or one or
     more predecessor Senior Debt Securities) is registered at the close of
     business on the Regular Record Date for such interest;

          (5) if other than the location specified in this prospectus, the place
     or places where the principal of and premium, if any, and interest on
     Senior Debt Securities will be payable;

          (6) the period or periods within which, the price or prices at which
     and the terms and conditions upon which such Senior Debt Securities will,
     pursuant to any mandatory sinking fund provisions or otherwise, or may,
     pursuant to any optional sinking fund provisions or otherwise, be redeemed
     in whole or in part by BOK Financial Corporation;

          (7) the period or periods within which, the price or prices at which
     and the terms and conditions upon which such Senior Debt Securities may be
     repaid, in whole or in part, at the option of the holders thereof;

          (8) if other than denominations of $1,000 and any integral multiple
     thereof, the denominations in which such Senior Debt Securities will be
     issuable;

          (9) if other than the principal amount thereof, the portion of the
     principal amount of such Senior Debt Securities that will be payable upon
     declaration of acceleration of the maturity thereof;

          (10) the currency or currency unit of payment of principal of and
     premium, if any, and interest on such Senior Debt Securities, and any index
     used to determine the amount of principal of or premium, if any, and
     interest on such Senior Debt Securities;

          (11) whether such Senior Debt Securities are to be issuable as Global
     Securities (as defined below) and, in such case, the initial securities
     depositary with respect thereto and the circumstances under which such
     Global Security may be exchanged for definitive securities; and

          (12) any other material terms of such Senior Debt Securities.

  Form, Registration and Transfer

     Unless otherwise indicated in the applicable prospectus supplement,
principal of, and premium, if any, and interest, if any, on Senior Debt
Securities will be payable, and Senior Debt Securities will be transferable, at
the agency or office of BOK Financial Corporation maintained for such purpose in
the Borough of Manhattan, The City of New York, except that interest may be paid
at the option of BOK Financial Corporation by check mailed to the address of the
holder entitled thereto as it appears on the applicable Security Register (as
defined in the applicable Indenture).

     Unless otherwise indicated in the applicable prospectus supplement, Senior
Debt Securities will be issued only in fully registered form, without coupons,
in denominations of $1,000 and any integral multiple thereof. The Indentures
provide that Senior Debt Securities of any series may be issuable in permanent
global form. See "GLOBAL SECURITIES" below. No service charge will be made for
any registration of transfer or exchange of the Senior Debt Securities, but BOK
Financial Corporation may require payment of a sum sufficient to cover any tax
or other governmental charge payable in connection therewith.

  Limitation on Disposition of Voting Stock of Principal Subsidiary Banks

     The Indenture contains a covenant by BOK Financial Corporation that it will
not sell, assign, transfer, grant a security interest in or otherwise dispose of
any shares of, securities convertible into or options, warrants or rights to
subscribe for or purchase shares of, Voting Stock (as defined below) (other than
directors' qualifying shares) of any Principal Subsidiary Bank (as defined
below) and that it will not

                                        6
<PAGE>   22

permit any Principal Subsidiary Bank to issue (except to BOK Financial
Corporation) any shares of, securities convertible into, or options, warrants or
rights to subscribe for or purchase shares of, Voting Stock of any Principal
Subsidiary Bank, except for sales, assignments, transfers, grants of security
interests or other dispositions that:

          (1) are for fair market value on the date thereof, as determined by
     the Board of Directors of BOK Financial Corporation (which determination
     shall be conclusive) and, after giving effect to such disposition and to
     any possible dilution, BOK Financial Corporation will own not less than 80%
     of the shares of Voting Stock of such Principal Subsidiary Bank then issued
     and outstanding free and clear of any security interest;

          (2) are made in compliance with an order of a court or regulatory
     authority of competent jurisdiction, as a condition imposed by any such
     court or authority permitting the acquisition by BOK Financial Corporation,
     directly or indirectly, of any other bank or entity the activities of which
     are legally permissible for a bank holding company or a subsidiary thereof
     to engage in, or as an undertaking made to such authority in connection
     with such an acquisition;

          (3) are made where such Principal Subsidiary Bank, having obtained any
     necessary regulatory approvals, unconditionally guarantees payment when due
     of the principal of and premium, if any, and interest on the Senior Debt
     Securities; or

          (4) are made to BOK Financial Corporation or any Wholly-Owned
     Subsidiary (as defined in the Indenture) if such Wholly-Owned Subsidiary
     agrees to be bound by this covenant and BOK Financial Corporation agrees to
     maintain such Wholly-Owned Subsidiary as a Wholly-Owned Subsidiary.
     Notwithstanding the foregoing, any Principal Subsidiary Bank may be merged
     into or consolidated with another banking institution organized under the
     laws of the United States, any State thereof or the District of Columbia
     if, after giving effect to such merger or consolidation, BOK Financial
     Corporation or any Wholly-Owned Subsidiary owns at least 80% of the Voting
     Stock of such other banking institution then issued and outstanding free
     and clear of any security interest and if, immediately after giving effect
     thereto and treating any such resulting banking institution thereafter as
     such Principal Subsidiary Bank and as a Subsidiary for purposes of the
     Indenture, no Event of Default, and no event that, after the giving of
     notice or lapse of time or both, would become an Event of Default, has
     occurred and is continuing. A "Principal Subsidiary Bank" is defined in the
     Indenture to mean any Subsidiary (as defined in the Indenture) that is a
     bank and has total assets equal to 30% or more of the consolidated assets
     of BOK Financial Corporation determined as of the date of the most recent
     audited financial statements of such entities. At present, the only
     Principal Subsidiary Bank is the Bank of Oklahoma, National Association.
     "Voting Stock" is defined in the Indenture to mean stock of the class or
     classes having general voting power under ordinary circumstances to elect
     at least a majority of the board of directors, managers or trustees of such
     corporation (irrespective of whether or not at the time stock of any other
     class or classes will have contingent voting rights).

  Consolidation, Merger and Sale of Assets

     The Indenture provides that BOK Financial Corporation may not consolidate
with or merge into any other person or transfer its properties and assets
substantially as an entirety to any person unless:

          (1) the person formed by such consolidation or into which BOK
     Financial Corporation is merged or the person to which the properties and
     assets of BOK Financial Corporation are so transferred is a corporation,
     partnership or trust organized and validly existing under the laws of the
     United States, any State thereof or the District of Columbia and expressly
     assumes by a supplemental indenture the payment of the principal of and
     premium, if any, and interest on the Senior Debt Securities, as the case
     may be, and the performance of the other covenants of BOK Financial
     Corporation under the applicable Indenture;

                                        7
<PAGE>   23

          (2) immediately after giving effect to such transaction, no Event of
     Default or Default (as defined below), as applicable, and no event that,
     after notice or lapse of time or both, would become an Event of Default or
     Default, as applicable, has occurred and is continuing; and

          (3) certain other conditions are met.

  Defaults

     An "Event of Default" is defined in the Indenture, with respect to Senior
Debt Securities of any series issued thereunder, as:

          (1) default in the payment of principal of or premium, if any, on any
     Debt Security of that series at maturity;

          (2) default for 30 days in the payment of interest on any Debt
     Security of that series;

          (3) default in the deposit of any sinking fund payment when due in
     respect of that series;

          (4) default in the performance, or breach, of any other covenant or
     warranty of BOK Financial Corporation in the Indenture or in the Senior
     Debt Securities of that series, continued for 60 days after written notice
     to BOK Financial Corporation by the Trustee or to BOK Financial Corporation
     and the Trustee by the holders of not less than 25% of the aggregate
     principal amount of the outstanding Senior Debt Securities of that series;

          (5) failure to pay when due any indebtedness of BOK Financial
     Corporation or any Principal Subsidiary Bank for borrowed money in excess
     of $5,000,000, or acceleration of the maturity of any such indebtedness in
     excess of such amount if acceleration results from a default under the
     instrument giving rise to such indebtedness and is not annulled within 60
     days after due notice, unless in either case such default is contested in
     good faith by appropriate proceedings;

          (6) certain events of bankruptcy, insolvency or reorganization of BOK
     Financial Corporation or any Principal Subsidiary Bank; and

          (7) any other Event of Default that may be provided for with respect
     to Senior Debt Securities of that series.

     The Indenture provides that, if any Event of Default with respect to Senior
Debt Securities of any series at the time outstanding thereunder occurs and is
continuing, either the Trustee or the holders of not less than 25% in aggregate
principal amount of the outstanding Senior Debt Securities of that series may
declare the principal amount of all Senior Debt Securities of that series to be
due and payable immediately (provided, that no such declaration is required upon
certain events of bankruptcy, insolvency or reorganization), but upon certain
conditions such declaration may be annulled and past defaults (except, unless
theretofore cured, a default in payment of principal of or premium, if any, or
interest on the Senior Debt Securities of that series and certain other
specified defaults) may be waived by the holders of a majority in principal
amount of the outstanding Senior Debt Securities of that series on behalf of the
holders of all Senior Debt Securities of that series. In the event of the
bankruptcy, insolvency or reorganization of BOK Financial Corporation, the
claims of holders of the Senior Debt Securities would be subject as to
enforcement to the broad equity power of a United States Bankruptcy Court, and
to the determination by that court of the nature of the rights of such holders.

     The Indenture contains a provision entitling the Trustee, subject to the
duty of the Trustee upon the occurrence and continuation of an Event of Default
to act with the required standard of care, to be indemnified by the holders of
any series of outstanding Senior Debt Securities thereunder before proceeding to
exercise any right or power under the Indenture at the request of the holders of
such series of Senior Debt Securities. The Indenture provides that the holders
of a majority in aggregate principal amount of outstanding Senior Debt
Securities of any series thereunder may direct the time, method and place of
conducting any proceeding for any remedy available to the Trustee, or exercising
any trust or other power conferred on the Trustee, with respect to the Senior
Debt Securities of such series, provided
                                        8
<PAGE>   24

that the Trustee may decline to act if such direction is contrary to law or the
Indenture or would involve the Trustee in personal liability.

     BOK Financial Corporation will file annually with the Trustee a certificate
as to compliance with all conditions and covenants in the Indenture.

  Defeasance and Discharge

     The Indenture provides that the terms of any series of Senior Debt
Securities issued thereunder may provide that BOK Financial Corporation may
terminate certain of its obligations under such Indenture with respect to the
Senior Debt Securities of such series on the terms and subject to the conditions
contained in such Indenture, by (a) depositing irrevocably with the applicable
Trustee as trust funds in trust:

          (1) in the case of Senior Debt Securities denominated in a foreign
     currency, money in such foreign currency or Foreign Government Obligations
     (as defined below) of the foreign government or governments issuing such
     foreign currency,

          (2) in the case of Senior Debt Securities denominated in U.S. dollars,
     U.S. dollars or U.S. Government Obligations (as defined below), in each
     case in an amount that through the payment of interest, principal or
     premium, if any, in respect thereof in accordance with their terms will
     provide (without any reinvestment of such interest, principal or premium),
     not later than one business day before the due date of any payment, money,
     or

          (3) a combination of money and U.S. Government Obligations or Foreign
     Government Obligations, as applicable, sufficient to pay the principal of
     or premium, if any, and interest on, the Senior Debt Securities of such
     series as such are due.

and (b) satisfying certain other conditions precedent specified in the
applicable Indenture. Such deposit and termination is conditioned, among other
things, upon BOK Financial Corporation's delivery of (a) an opinion of
independent counsel that the holders of the Senior Debt Securities of such
series will have no federal income tax consequences as a result of such deposit
and termination and (b) if the Senior Debt Securities of such series are then
listed on an exchange, an opinion of counsel that the Senior Debt Securities of
such series will not be delisted as a result of the exercise of this option.
Such termination will not relieve BOK Financial Corporation of its obligation to
pay when due the principal of, and interest on the Senior Debt Securities of
such series if the Senior Debt Securities of such series are not paid from the
money, Foreign Government Obligations or U.S. Government Obligations held by the
applicable Trustee for payment thereof.

     "U.S. Government Obligations" means securities that are (1) direct
obligations of the United States of America for the payment of which its full
faith and credit is pledged or (2) obligations of a person controlled or
supervised by and acting as an agency or instrumentality of the United States of
America the payment of which is unconditionally guaranteed as a full faith and
credit obligation by the United States of America, that, in either case, under
clauses (1) or (2) are not callable or redeemable at the option of the issuer
thereof. "Foreign Government Obligations" means securities denominated in a
foreign currency that are (1) direct obligations of a foreign government for the
payment of which its full faith and credit is pledged or (2) obligations of a
person controlled or supervised by and acting as an agency or instrumentality of
a foreign government the payment of which is unconditionally guaranteed as a
full faith and credit obligation by such foreign government, that, in either
case, under clauses (1) or (2) are not callable or redeemable at the option of
the issuer thereof.

     The applicable prospectus supplement will state whether any defeasance
provisions of the applicable Indenture will apply to the Senior Debt Securities
offered thereby.

                                        9
<PAGE>   25

  Modification and Waiver

     Certain modifications and amendments of each of the Indentures may be made
by BOK Financial Corporation and the applicable Trustee only with the consent of
the holders of not less than a majority in aggregate principal amount of the
outstanding Senior Debt Securities of each series issued under such Indenture
and affected by the modification or amendment, provided that no such
modification or amendment may, without the consent of the holder of each
outstanding Debt Security issued under such Indenture and affected thereby:

          (1) change the Stated Maturity (as defined in the applicable
     indenture) of the principal of, or any installment of principal of or
     interest on, any such Debt Security;

          (2) reduce the principal amount of, or the premium, if any, or the
     interest, if any, on, any such Debt Security;

          (3) change the place of payment where, or the coin or currency or
     currency unit in which, any principal of, or premium, if any, or interest
     on, any such Debt Security is payable;

          (4) impair the right to institute suit for the enforcement of any such
     payment on or after the Stated Maturity thereof (or, in the case of
     redemption, on or after the Redemption Date (as defined in the applicable
     Indenture));

          (5) reduce the above-stated percentage of outstanding Senior Debt
     Securities of any series the consent of the holders of which is necessary
     to modify or amend the applicable Indenture; or

          (6) modify the foregoing requirements or reduce the percentage of
     aggregate principal amount of outstanding Senior Debt Securities of any
     series required to be held by holders seeking to waive compliance with
     certain provisions of the applicable Indenture or seeking to waive certain
     defaults.

     The holders of not less than a majority in aggregate principal amount of
the outstanding Senior Debt Securities of any series may on behalf of the
holders of all Senior Debt Securities of that series waive, insofar as that
series is concerned, compliance by BOK Financial Corporation with certain
restrictive provisions of the applicable Indenture. The holders of not less than
a majority in aggregate principal amount of the outstanding Senior Debt
Securities of any series may on behalf of the holders of all Senior Debt
Securities of that series waive any past default under the applicable Indenture
with respect to that series, except a default in the payment of the principal
of, or premium, if any, or interest on, any Debt Security of that series or in
respect of a covenant or provision that under the applicable Indenture cannot be
modified or amended without the consent of the holder of each outstanding Debt
Security issued thereunder of the series affected.

     Certain modifications and amendments of each of the Indentures may be made
by BOK Financial Corporation and the applicable Trustee without the consent of
holders of the outstanding Senior Debt Securities issued under such Indenture.

     Each Indenture provides that in determining whether the holders of the
requisite principal amount of the outstanding Senior Debt Securities issued
under such Indenture have given any request, demand, authorization, direction,
notice, consent or waiver thereunder or are present at a meeting of holders of
Senior Debt Securities for quorum purposes, the principal amount of a Debt
Security denominated in a foreign currency or currency unit will be the U.S.
dollar equivalent, determined on the date of original issuance of such Debt
Security, of the principal amount of such Debt Security or, in the case of an
Original Issue Discount Security, the U.S. dollar equivalent, determined on the
date of original issuance of such Debt Security, of the amount determined as
provided above.

  Title

     BOK Financial Corporation, the applicable Trustee and any agent of BOK
Financial Corporation or the applicable Trustee may treat the registered owner
of any Debt Security as the absolute owner thereof

                                       10
<PAGE>   26

(whether or not such Debt Security is overdue and notwithstanding any notice to
the contrary) for the purpose of making payment and for all other purposes. See
"GLOBAL SECURITIES" below.

  Replacement of Senior Debt Securities

     Any mutilated Debt Security will be replaced by BOK Financial Corporation
at the expense of the holder upon surrender of such Debt Security to the
applicable Trustee. Senior Debt Securities that are destroyed, lost or stolen
will be replaced by BOK Financial Corporation at the expense of the holder upon
delivery to the applicable Trustee of evidence of the destruction, loss or theft
thereof satisfactory to BOK Financial Corporation and the applicable Trustee. In
the case of a destroyed, lost or stolen Debt Security, an indemnity satisfactory
to the applicable Trustee and BOK Financial Corporation may be required at the
expense of the holder of such Debt Security before a replacement Debt Security
will be issued.

  Governing Law

     The Indentures and the Senior Debt Securities will be governed by, and
construed in accordance with, the laws of the State of New York.

  Concerning the Trustees

     The Trustee will be named in the applicable prospectus supplement.

     Any Trustee may resign or be removed with respect to one or more series of
Senior Debt Securities and a successor Trustee may be appointed to act with
respect to such series. If two or more persons are acting as Trustee with
respect to different series of Senior Debt Securities, each such Trustee will be
a Trustee of a trust under the related Indenture separate and apart from the
trust administered by any other such Trustee, and any action described herein to
be taken by the "Trustee" may then be taken by each such Trustee with respect
to, and only with respect to, the one or more series of Senior Debt Securities
for which it is Trustee.

     In the ordinary course of business, BOK Financial Corporation and its
subsidiaries may conduct banking transactions with a Trustee, and such Trustee
and its affiliates may conduct banking transactions with BOK Financial
Corporation and its subsidiaries.

  Ratings

     Particular series of Senior Debt Securities may be rated by one or more
nationally recognized statistical rating agencies. the rating agency or agencies
and rating or ratings to be assigned with respect to a series of Senior Debt
Securities will be specified in the prospectus supplement for the series of
Senior Debt Securities.

                               GLOBAL SECURITIES

     Unless otherwise specified in the applicable prospectus supplement, the
Senior Debt Securities will be issued in the form of one or more global
certificates (collectively, with respect to each series or issue of Securities,
the "Global Security") registered in the name of a depositary or a nominee of a
depositary. Unless otherwise specified in the applicable prospectus supplement,
the depositary will be The Depository Trust Company ("DTC"). BOK Financial
Corporation has been informed by DTC that its nominee will be Cede & Co.
("Cede"). Accordingly, Cede is expected to be the initial registered holder of
all Senior Debt Securities that are issued in global form. No person that
acquires a beneficial interest in such Senior Debt Securities will be entitled
to receive a certificate representing such person's interest in the Senior Debt
Securities except as set forth herein or in the applicable prospectus
supplement. Unless and until definitive Senior Debt Securities are issued under
the limited circumstances described below, all references to actions by holders
of Senior Debt Securities issued in global form shall refer to actions taken by
DTC upon instructions from its Participants (as defined below), and all
references herein to payments and
                                       11
<PAGE>   27

notices to holders shall refer to payments and notices to DTC or Cede, as the
registered holder of such Senior Debt Securities.

     DTC is a company organized under the New York Banking Law, a "banking
organization" within the meaning of the New York Banking Law, that it is a
member of the Federal Reserve System, a "clearing corporation" within the
meaning of the New York Uniform Commercial Code and a "clearing agency"
registered pursuant to Section 17A of the Exchange Act, and was created to hold
securities for its participating organizations ("Participants") and to
facilitate the clearance and settlement of securities transactions among
Participants through electronic book-entry, thereby eliminating the need for
physical movement of certificates. Participants include securities brokers and
dealers, banks, trust companies and clearing corporations, and may include
certain other organizations. Indirect access to the DTC system also is available
to others such as banks, brokers, dealers and trust companies that clear through
or maintain a custodial relationship with a Participant, either directly or
indirectly ("Indirect Participants").

     Persons that are not Participants or Indirect Participants but desire to
purchase, sell or otherwise transfer ownership of, or other interests in Senior
Debt Securities may do so only through Participants and Indirect Participants.
Under a book-entry format, holders may experience some delay in their receipt of
payments, as such payments will be forwarded by the agent designated by BOK
Financial Corporation to Cede, as nominee for DTC. DTC will forward such
payments to its Participants, which thereafter will forward them to Indirect
Participants or holders. Holders will not be recognized by BOK Financial
Corporation or by the applicable registrar, transfer agent, Trustee or
Depositary, or their agents, as registered holders of the Senior Debt Securities
entitled to the benefits of the applicable Indenture. Beneficial owners that are
not Participants will be permitted to exercise their rights as such only
indirectly through and subject to the procedures of Participants and, if
applicable, Indirect Participants.

     Under the rules, regulations and procedures creating and affecting DTC and
its operations as currently in effect (the "Rules"), DTC will be required to
make book-entry transfers of Senior Debt Securities among Participants and to
receive and transmit payments to Participants. Participants and Indirect
Participants with which beneficial owners of Senior Debt Securities have
accounts with respect to the Senior Debt Securities similarly are required by
the Rules to make book-entry transfers and receive and transmit such payments on
behalf of their respective account holders.

     Because DTC can act only on behalf of Participants, who in turn act only on
behalf of Participants or Indirect Participants, and on behalf of certain banks,
trust companies and other persons approved by it, the ability of a beneficial
owner of Senior Debt Securities issued in global form to pledge such Senior Debt
Securities to persons or entities that do not participate in the DTC system, or
to otherwise act with respect to such Senior Debt Securities, may be limited due
to the unavailability of physical certificates for such Senior Debt Securities.

     DTC has advised BOK Financial Corporation that DTC will take any action
permitted to be taken by a registered holder of any Senior Debt Securities under
the applicable Indenture only at the direction of one or more Participants to
whose accounts with DTC such Senior Debt Securities are credited.

     Unless otherwise specified in the applicable prospectus supplement, a
Global Security will be exchangeable for the relevant definitive Senior Debt
Securities registered in the names of persons other than DTC or its nominee only
if (1) DTC notifies BOK Financial Corporation that it is unwilling or unable to
continue as depository for such Global Security or if at any time DTC ceases to
be a clearing agency registered under the Exchange Act at a time when DTC is
required to be so registered in order to act as such depository, (2) BOK
Financial Corporation determines that such Global Security shall be so
exchangeable or (3) there has occurred and is continuing an Event of Default or
an event that, with the giving of notice or lapse of time, or both, would
constitute an Event of Default with respect to such Senior Debt Securities. Any
Global Security that is exchangeable pursuant to the preceding sentence will be
exchangeable for Senior Debt Securities registered in such names as DTC directs.

     Upon the occurrence of any event described in the immediately preceding
paragraph, DTC is generally required to notify all Participants of the
availability through DTC of definitive Senior Debt

                                       12
<PAGE>   28

Securities. Upon surrender by DTC of the Global Security representing the
Securities and delivery of instructions for re-registration, the registrar,
transfer agent, Trustee or Depositary, as the case may be, will reissue the
Senior Debt Securities as definitive Senior Debt Securities, and thereafter such
persons will recognize the holders of such definitive Senior Debt Securities as
registered holders of Senior Debt Securities entitled to the benefits of the
applicable Indenture.

     Except as described above, a Global Security may not be transferred except
as a whole by DTC to a nominee of DTC or by a nominee of DTC to DTC or another
nominee of DTC or to a successor depositary appointed by BOK Financial
Corporation. Except as described above, DTC may not sell, assign, transfer or
otherwise convey any beneficial interest in a Global Security evidencing all or
part of any Senior Debt Securities unless such beneficial interest is in an
amount equal to an authorized denomination for such Senior Debt Securities.

                                USE OF PROCEEDS

     We will use the proceeds of the sale of the Senior Debt Securities for:

     - acquisitions

     - capital improvements

     - repayment of short term bank borrowings

     - start-up of new banking and bank related businesses

     - expansion of existing business

     - general working capital

     We will tell you in the prospect supplement for what purpose we plan to use
the proceeds of any particular series of the Senior Debt Securities.

                              PLAN OF DISTRIBUTION

     We may sell the offered securities (a) through agents; (b) through
underwriters or dealers; or (c) directly to one or more purchasers.

  By Agents

     Offered securities may be sold through agents designated by us. The agents
agree to use their reasonable best efforts to solicit purchases for the period
of their appointment.

  By Underwriters

     If underwriters are used in the sale, the offered securities will be
acquired by the underwriters for their own account. The underwriters may resell
the securities in one or more transactions, including negotiated transactions,
at a fixed public offering price or at varying prices determined at the time of
sale. The obligations of the underwriters to purchase the securities will be
subject to certain conditions. The underwriters will be obligated to purchase
all the securities of the series offered if any of the securities are purchased.
Any initial public offering price and any discounts or concessions allowed or
re-allowed or paid to dealers may be changed from time to time.

  Direct Sales

     Offered securities may also be sold directly by us. In this case, no
underwriters or agents would be involved.

                                       13
<PAGE>   29

  General Information

     Underwriters, dealers and agents that participate in the distribution of
the offered securities may be underwriters as defined in the Securities Act of
1933 (the "Act"), and any discounts or commissions received by them from us and
any profit on the resale of the offered securities by them may be treated as
underwriting discounts and commissions under the Act. Any underwriters or agents
will be identified and their compensation described in a prospectus supplement.

     We may have agreements with the underwriters, dealers and agents to
indemnify them against certain civil liabilities, including liabilities under
the Act, or to contribute with respect to payments which the underwriters,
dealers or agents may be required to make.

     Underwriters, dealers and agents may engage in transactions with, or
perform services for, us or our subsidiaries in the ordinary course of their
businesses.

                       RATIO OF EARNINGS TO FIXED CHARGES

<TABLE>
<CAPTION>
                                           SIX MONTHS
                                             ENDED
                                            JUNE 30,              YEAR ENDED DECEMBER 31,
                                         --------------      ----------------------------------
                                         1998      1997      1996      1995      1994      1993
                                         ----      ----      ----      ----      ----      ----
<S>                                      <C>       <C>       <C>       <C>       <C>       <C>
Ratio of Earnings to Fixed Charges:
  Excluding Interest on Deposits.......  2.68      2.21      2.54      2.02      2.81      6.80
  Including Interest on Deposits.......  1.55      1.43      1.43      1.40      1.57      1.73
</TABLE>

     These computations include BOK Financial Corporation and its subsidiaries.
For these ratios, "earnings" are determined by adding "fixed charges" to income
from continuing operations before taxes. "Fixed charges" consist of interest on
all debt and amortization of premiums or discounts associated with debt.

                     VALIDITY OF THE SENIOR DEBT SECURITIES

     Unless otherwise indicated in the applicable prospectus supplement, the
validity of and Senior Debt Securities offered hereby will be passed upon for
BOK Financial Corporation by its counsel, Frederic Dorwart, Esquire, Tulsa,
Oklahoma.

                                    EXPERTS

     The consolidated financial statements of BOK Financial Corporation
incorporated by reference in BOK Financial Corporation's Annual Report (Form
10-K) for the year ended December 31, 1997 have been audited by Ernst & Young
LLP, independent auditors, as set forth in their report incorporated by
reference therein and incorporated herein by reference. Such consolidated
financial statements are incorporated herein by reference in reliance upon such
report given upon the authority of such firm as experts in accounting and
auditing.

                                       14
<PAGE>   30

                                 June    , 1999

                        [BOK FINANCIAL CORPORATION LOGO]

                                  $100,000,000

                       [      ]% SENIOR NOTES DUE 200

             -----------------------------------------------------
                       PRELIMINARY PROSPECTUS SUPPLEMENT
             -----------------------------------------------------

                          Joint Book Running Managers

BANC OF AMERICA SECURITIES LLC                             CHASE SECURITIES INC.


© 2022 IncJournal is not affiliated with or endorsed by the U.S. Securities and Exchange Commission