EXHIBIT 99.2



                             C O N F I D E N T I A L









                              TRANSACTION DOCUMENT
                                (Stock Purchase)





                            STOCK PURCHASE AGREEMENT



                                      AMONG



                           BOK FINANCIAL CORPORATION,

                          BALTZ FAMILY PARTNERS, LTD.,

                         UNITED BANKS OF COLORADO, INC.



                                       AND



                            FIRST UNITED BANK, N.A.,



                         Agreement Date of May 23, 2007

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                                TABLE OF CONTENTS

                                                                     Page
1.       Purpose of this Stock Purchase Agreement........................1

2.       Purchase of UBC Common Stock....................................1

3.       Purchase Price..................................................3

4.       Representations and Warranties of BFP, UBC and Bank.............4

5.       Representations and Warranties of BOKF..........................8

6.       Covenants.......................................................9

7.       Conditions Precedent to Closing by BOKF........................15

8.       Conditions Precedent to Closing by UBC and Bank................16

9.       Closing........................................................16

10.      The General Escrow.............................................18

11.      Loan Escrow....................................................19

12.      Break-Up Fee...................................................20

13.      Miscellaneous Provisions.......................................20


                            STOCK PURCHASE AGREEMENT

         This Stock Purchase Agreement ("Stock Purchase Agreement" or
"Agreement") is made as of May 23, 2007 (the "Agreement Date") among the
following parties (the "Parties"):

(i) BOK Financial Corporation, an Oklahoma corporation, ("BOKF");

(ii) Baltz Family Partners, Ltd, a Colorado limited partnership ("BFP");

(iii) First United Bank, NA ("Bank"); and,

(iv) United Banks of Colorado, Inc., a Colorado corporation ("UBC").

         In consideration of the mutual covenants contained herein, the adequacy
of which is hereby expressly acknowledged, and intending to be legally bound
hereby, the Parties hereby agree as follows:

1. Purpose of this Stock Purchase Agreement. The purpose of this Stock Purchase
Agreement is as follows:

1.1. UBC is a bank holding company organized under the laws of Colorado with
offices in Englewood, Colorado. UBC is subject to regulation by the Board of
Governors of the Federal Reserve System ("FRB"). UBC owns all of the issued and
outstanding capital stock of Bank (headquartered in Englewood, Colorado). The
authorized capital stock of UBC consists solely of a single class of 50,000
shares of common stock of a par value of $5.00 per share of which 26,000 shares
are issued and outstanding at the Agreement Date (the "UBC Common Stock").

1.2. Bank is a national bank organized in accordance with the laws of the United
States of America. The authorized capital stock of Bank consists solely of a
single class of 250,000 shares of common stock of a par value of $10.00 per
share of which 250,000 shares are issued and outstanding at the Agreement Date
("Bank Common Stock").

1.3. BFP is a Colorado limited partnership and the sole shareholder of UBC. BFP
has four (4) limited partners as follows: Martha J. Baltz, Stephen P. Baltz,
Kimberly A. Baltz and Jennifer L. Baltz. Stephen P. Baltz and Martha J. Baltz
are the general partners of BFP. There are no other BFP Partners. For purposes
of this Agreement, "BFP Partners" means Martha J. Baltz, Stephen P. Baltz,
Kimberly A. Baltz and Jennifer L. Baltz.

1.4. BOKF is a financial holding company organized under the laws of the State
of Oklahoma. BOKF is subject to regulation by the FRB.

1.5. The purpose of this Stock Purchase Agreement is to set forth the terms and
conditions on which BOKF shall purchase all the Bank Common Stock from UBC.

2. Purchase of UBC Common Stock. Subject to the terms and conditions set forth
herein, at the Closing (as herein after defined), BFP shall sell, convey,
transfer, and deliver to BOKF certificates representing the UBC Common Stock,
and BOKF shall purchase from BFP all the

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UBC  Common  Stock in  consideration  of the  purchase  price  set forth in this
Agreement (the "Transaction").

3. Purchase Price.

3.1. As total consideration for the purchase and sale of the UBC Common Stock
pursuant to this Agreement, BOKF shall pay to BFP the following (the
"Transaction Consideration"):

3.1.1. At Closing, an amount of United States Dollars equal to the Cash
Consideration (as hereafter defined) less the Escrow Amounts (as hereafter
defined) (the "Closing Amount"); and,

3.1.2. Upon termination of the Escrow Account, the remaining Escrow Amounts, if
any, as provided in Sections 10 and 11 herein.

3.2. The Cash Consideration shall equal (i) Forty Three Million Dollars
($43,000,000) less (ii) the Transaction Costs (as hereafter defined) and (iii)
the "Home Sale Loss" (as hereinafter defined).

3.3. For purposes of this Stock Purchase Agreement, "Transaction Costs" means:
(i) investment banking fees in excess of $250,000 that are payable to Carson
Medlin Company upon consummation of the Transaction; (ii) legal fees paid (or
payable) to Bracewell & Giuliani LLP in excess of $50,000 that have been
incurred in connection with the negotiation of this Agreement and the
consummation of the Transaction; and (iii) change in control payments in excess
of $25,000 that are payable to the Bank's officers and directors as a result of
the consummation of the Transaction.

3.4. For purposes of this Stock Purchase Agreement, the "Escrow Amounts" shall
be:

3.4.1. One Million Five Hundred Dollars ($1,500,000) to be deposited in the
General Escrow established in accordance with Section 10 (the "General Escrow");
and

3.4.2. Eight Million Dollars ($8,000,000) to be deposited in the Loan Escrow
established in accordance with Section 11 (the "Loan Escrow").

4. Representations and Warranties of BFP, UBC and Bank. BFP, UBC and Bank hereby
jointly and severally represent and warrant to BOKF that, now and at the time of
Closing:

4.1. Incorporation and Corporate Power. UBC is a corporation duly organized,
validly existing and in good standing under the laws of the State of Colorado.
Except as set forth on Schedule 4.1, Bank is a national bank duly organized,
validly existing and in good standing under the laws of the United States. BFP
is a limited partnership, organized, validly existing and in good standing under
the laws of the State of Colorado. Except as set forth on Schedule 4.1, Bank has
all the corporate power and authority necessary and required to own its
properties and to conduct its business as such business is now being conducted.
Except as set forth on Schedule 4.1, each of UBC and Bank (A) is in material
compliance with all applicable provisions of all applicable federal, state and
local statutes, laws, regulations, ordinances and other requirements

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of any governmental authorities (including,  but not limited to, whether similar
or  dissimilar,  the Bank Holding  Company Act of 1956,  the  Colorado  Business
Corporation  Act,  Title 12 of the Code of  Federal  Regulations  (the  "Federal
Banking Code") and the filing of all  administrative  reports and the payment of
all material  fees) in effect as of the date of this Stock  Purchase  Agreement,
and (B) shall be in material compliance therewith at the time of Closing.

4.2. Capital. The BFP Partners are the sole partners of BFP. BFP is the sole
shareholder of UBC. UBC owns all of the issued and outstanding Bank Common
Stock. The Bank Common Stock is and at the Closing will be all of the issued and
outstanding capital stock of Bank and will be owned by UBC.

4.3. Capitalization of Bank. The Bank Common Stock is validly issued and
outstanding, fully paid and (except as set forth in 12 U.S.C. ss. 55)
non-assessable.

4.3.1. There are no outstanding subscriptions, conversion privileges, calls,
warrants, options or agreements obligating the Bank to issue, sell or dispose
of, or to purchase, redeem or otherwise acquire any shares of their capital
stock (collectively, "options and rights"). At the Closing, there will be no
outstanding options or rights.

4.3.2. None of the Bank Common Stock has been issued or disposed of, or will as
of the Closing have been issued or disposed of, in violation of any preemptive
rights of any shareholder nor in violation of any agreement to which UBC or Bank
was or is a party. Bank has no subsidiaries and does not own, nor have the right
or obligation to acquire, any equity securities of any corporation, limited
liability company, partnership or other legal entity.

4.3.3. UBC is the lawful owner of the Bank Common Stock, free and clear of all
security interests, liens, encumbrances, equities and other charges.

4.4. Non-Violation of Other Agreements. The execution and delivery of this Stock
Purchase Agreement, and the compliance with its terms and provisions BFP, UBC
and Bank (including the execution and delivery of any document required to be
executed by BFP, UBC or Bank) will not breach any material agreement, lease, or
obligation, whether similar or dissimilar, by which BFP, UBC or Bank is bound.

4.5. Financial Statements. UBC has delivered to BOKF, or will have delivered to
BOKF prior to the Closing as soon as future financial statements are available,
copies of the following ("Financial Statements"):

4.5.1.   Financial Statements for UBC (Unaudited) as of and for the periods
ending December 31, 2005 and 2006;

4.5.2. Reports of Condition and Income as filed with the Federal Deposit
Insurance Corporation for Bank, as of and for the periods ending December 31,
2004, 2005, and 2006;

4.5.3. Financial Statements (Audited) Bank, as of and for the periods ending
December 31, 2006 and the most recent monthly financial statements available as
of the Closing; and,

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4.5.4. The most recent monthly financial statements as are available as of the
Closing.

         The Financial Statements described in Sections 4.5.1 and 4.5.2, (a)
have been prepared or will have been prepared in accordance with generally
accepted accounting principles, consistently applied and (b) fairly reflect the
financial condition and results of operations for the indicated periods. The
Financial Statements described in Sections 4.5.3 (including footnotes) and 4.5.4
(not including footnotes), (a) have been prepared or will have been prepared in
accordance with generally accepted accounting principles, consistently applied
and (b) fairly reflect the financial condition and results of operations for the
indicated periods, subject to normal year-end adjustments.

4.6. Material Liabilities. UBC and Bank have no liabilities (including, but not
limited to, whether similar or dissimilar, liabilities or obligations for taxes,
whether due or to become due) in excess of $25,000 except:

4.6.1. Those fully reflected or reserved against, or otherwise disclosed, in the
Financial Statements; and

4.6.2. Those specifically disclosed in the Schedule 4.6 to this Stock Purchase
Agreement.

4.7. Conduct of Business Prior to Closing. Except as set forth in Schedule 4.7,
since December 31, 2006, (A) Bank and UBC have carried on their businesses only
in the ordinary and normal course in a reasonable fashion in accordance with
industry standard, and (B) have not:

4.7.1. Incurred any material liabilities, commitments or obligations, contingent
or otherwise, or disposed of any of its assets, (for the purpose of this Section
4.7.1, material means $25,000 or more);

4.7.2. Incurred any bank or other institutional debt, or entered into any
agreement for the borrowing of money, except borrowing of federal funds or
borrowing from the Federal Home Loan Bank by Bank consistent with past
practices;

4.7.3. Suffered any material adverse change in the financial condition, assets,
liabilities, business or property of Bank or UBC taken as a whole; and/or

4.7.4. Made any material change in the manner in which business is conducted
(including, without limitation, branch closings, and any material change in
products offered to customers).

4.7.5. From the date of this Agreement to the date of Closing, neither Bank nor
UBC will voluntarily take any of the actions described in the foregoing
provisions of this Section 4.7 without the prior consent of BOKF, which consent
shall not be unreasonably withheld, delayed or denied.



4.8. Tax Returns/Reports.

4.8.1. Except as set forth on Schedule 4.8, Bank and UBC have duly filed all tax
reports and returns required to be filed by them and have duly paid all taxes
and other charges claimed to be due from them by federal, state and local taxing
authorities.

4.8.2. No waivers of the statute of limitation have been issued with respect to
unaudited years.

4.8.3. Neither Bank nor UBC have any knowledge of any facts which could
reasonably be expected to result in a material deficiency with respect to
unaudited tax returns which would result in a material adverse effect on Bank or
UBC taken as a whole.

4.9. Contracts and Commitments.

4.9.1. A list of all contracts and commitments, other than credit and lending,
deposit or borrowing transactions entered into in the ordinary course of
business by Bank or UBC which are material to the business, operations or
financial condition of Bank or UBC as of this date, is set forth on Schedule
4.9. For the purpose of Schedule 4.9 only, materiality shall mean those
contracts and commitments (including a series of related contracts or
commitments) for which payment or other consideration to be furnished by any
party is more than $25,000 a year or $100,000 over the remaining life of the
contract.

4.9.2. Bank and UBC have in all material respects performed and are performing
all contractual and other obligations required to be performed by them.

4.10. Litigation. Except as set forth in Schedule 4.10, there is not pending,
or, to the knowledge of BFP, UBC and Bank threatened, any claim, litigation,
proceeding, order of any court or governmental agency, or governmental
investigation or inquiry to which UBC or Bank is a party or which involves the
Bank's or UBC's business operations, any of its property or any property leased
by Bank which, individually or in the aggregate:

4.10.1. May reasonably result in any material adverse change in the financial
condition, business, assets, properties or operations of Bank or UBC; or,
4.10.2. May reasonably involve the expenditure of more than a total of $25,000
in legal fees or costs;

4.11. Brokerage Fees. Bank has not incurred, nor will it incur, directly or
indirectly, any liability for brokerage, finder's, financial advisor's or
agent's fees or commissions by virtue of any commitment made by any of them in
connection with this Stock Purchase Agreement or any transaction contemplated
hereby other than fees payable to Carson Medlin Company upon consummation of the
Transaction, which payment shall be deducted from the Transaction Consideration
to the extent it exceeds $250,000.

4.12. Required Corporate Action. The execution, delivery and consummation of
this Stock Purchase Agreement has been duly and validly authorized by the board
of directors of UBC and Bank and the BFP Partners, in accordance with the
requirements of federal banking

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law, the Colorado Business  Corporations  Act, the Colorado Limited  Partnership
Associations Act and all other applicable law.

4.13. Authorized Execution. This Stock Purchase Agreement has been duly executed
and delivered by duly authorized officers of UBC and Bank and BFP. This Stock
Purchase Agreement constitutes the legal, valid and binding agreement and
obligation of BFP, UBC and Bank, enforceable against each of them in accordance
with its terms, except as may be limited by applicable bankruptcy, insolvency,
moratorium, receivership, and other similar laws affecting the rights of
creditors generally.

4.14. Title to Assets; Encumbrances. Bank and UBC have good and valid title
(with respect to real estate, good and valid title shall mean such title as may
be insured on standard title insurance forms with no exceptions materially and
adversely affecting the value or use of the fee real estate) to its assets, and
in each case subject to no mortgage, pledge, lien, security interest,
conditional sale agreement, or other encumbrance of any nature whether similar
or dissimilar, except:

4.14.1. Such encumbrances which are purchase money security interests entered
into in the ordinary course of business consistent with past practice reflected
on their books and records;

4.14.2. Lessor's interests in leased tangible real and personal property
reflected on its books and records;

4.14.3. Such encumbrances for taxes and assessments not yet due and payable;

4.14.4. Encumbrances as do not materially detract from the value or interfere
with the use or operation of the asset subject thereto; and,

4.14.5. Repossessed and foreclosed assets acquired in satisfaction of debt
previously contracted.

4.15. Employees. Except as set forth on Schedule 4.15, none of the employees of
Bank or UBC is employed under any employment contract (oral or written) or is
the beneficiary of any compensation plan (oral or written) or is entitled to any
payment from Bank or UBC by reason of this Stock Purchase Agreement or the
Transaction and there are no employment contracts, management contracts,
consulting agreements, union contracts, labor agreements, pension plans, profit
sharing plans or employee benefit plans to which Bank or UBC is a party or by
which either of them is bound.

4.16. Environmental Laws. Except as set forth on Schedule 4.16, the existence,
use and operation of the assets of Bank and UBC is in material compliance with
all applicable statutes, rules and regulations including, without limiting the
generality of the foregoing, all environmental and zoning laws and the Americans
With Disabilities Act.

4.17. Loan Portfolio. (A) All loans and discounts shown on the Financial
Statements were and will be made in all material respects for good, valuable and
adequate consideration in the ordinary course of Bank's business, in accordance
in all material respects with sound banking

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practices,  and are not  subject  to any  material  known  defenses,  setoffs or
counterclaims, including without limitation any such as are afforded by usury or
truth in lending laws,  except as may be provided by  bankruptcy,  insolvency or
similar  laws or by  general  principles  of  equity;  (B) the  notes  or  other
evidences  of  indebtedness  evidencing  such  loans and all  forms of  pledges,
mortgages and other  collateral  documents and security  agreements are and will
be, in all material respects, enforceable, valid, true and genuine and what they
purport to be; and (C) Bank has  complied  and will  prior to the  Closing  Date
comply with all laws and regulations relating to such loans (including,  but not
limited to, obtaining  property  appraisals of a nature required by regulation),
or to the extent there has not been such compliance, such failure to comply will
not  materially  interfere  with  the  collection  of any such  loan or  require
additional action under applicable laws or regulations.

4.18. Zoning and Related Laws. All real property owned or leased by Bank or UBC
and the use thereof complies with all applicable laws, ordinances, regulations,
orders or requirements, including without limitation, building, zoning and other
laws, except as to any violations which would not have a material adverse affect
on the financial condition of Bank.

4.19. Compliance with Law. Except as set forth on Schedule 4.19, Bank and UBC
have all licenses, franchises, permits and other governmental authorizations
that are legally required to enable them to conduct their business as they are
currently doing so in all material respects and are in compliance with all
applicable laws and regulations. Without limiting the generality of the
foregoing, Bank has at all times maintained their employee benefit plans in
compliance with the Internal Revenue Code and the Employee Retirement Income
Security Act and all applicable rules and regulations promulgated pursuant
thereto. All data and reports respecting Bank employee benefit plans provided to
BOKF are complete and correct in all material respects. UBC has officers and
directors but no employees.

4.20. Agreements with Regulatory Agencies. Except as set forth on Schedule 4.20
and other than Stipulation and Consent to Issuance of Consent Order to the
Office of the Comptroller of the Currency dated October 5, 2006, neither Bank
nor UBC is subject to any cease-and-desist or other order issued by, or a party
to any written agreement or memorandum of understanding with or is a party to
any commitment letter or similar undertaking to, or is subject to any order or
directive, or is a recipient of any extraordinary supervisory letter from, or
has adopted any board resolutions at the request of (each a "Regulatory
Agreement") any regulatory agency that materially restricts the conduct of its
business or that in any manner relates to its capital adequacy, its credit
policies, its management or its business, nor has Bank or UBC been advised by
any regulatory agency that it is considering issuing or requesting any
Regulatory Agreement.

4.21. Actions From and After December 31, 2006. Except as set forth on Schedule
4.21, Bank has not taken any action from and after December 31, 2006 until the
date of this Agreement that is prohibited to be taken from and after the date of
this Agreement by the provisions of Section 6.3. Without limiting the generality
of the foregoing:

4.21.1. Bank has paid no dividends;

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4.21.2. From and after December 31, 2006, except as otherwise disclosed in the
Schedules to this Agreement, Bank has made no changes in the compensation of any
employees other than non-material cost of living and merit adjustments
consistent with past practices or as otherwise provided on Schedule 4.21.2.

4.22. Insurance. Bank and UBC have been continuously covered by those insurance
policies in the amounts, with the deductibles and for the periods identified on
Schedule 4.22 (the "Insurance Policies"). The Insurance Policies do not have any
exceptions or exclusions other than those typically found in policies of that
type.

4.23. Survival and Independence of Representations and Warranties. The
representations and warranties of BFP, UBC and Bank made in this Stock Purchase
Agreement shall survive the Closing notwithstanding any investigation or
knowledge of BOKF; provided BOKF shall give notice to the Agent (as herein after
defined) of any claim of a breach of any such representations and warranties on
or before the second anniversary of the Closing Date (the "Claim Notice
Deadline"). Each of the representations and warranties of UBC and Bank set forth
in this Stock Purchase Agreement is a separate and independent representation
and warranty, shall be cumulative of and in addition to all other warranties and
representations, and shall not limit or be interpreted to be in derogation of
any other representation or warranty made herein. Any disclosure made on any
Schedule hereto shall be applicable to the entire Agreement and not just one
representation or warranty.

4.24. Knowledge. As used herein, the knowledge of BFP, UBC and/or the Bank shall
mean the knowledge of any one or more of the following persons: the Chief
Executive Officer, Chief Financial Officer, Chief Lending Officer or Human
Resources Officer any member of the Board of Directors of UBC or the Bank have
or, in the reasonable exercise of their respective duties and responsibilities,
should have knowledge.

5. Representations and Warranties of BOKF. BOKF represents and warrants to BFP,
UBC and Bank that:

5.1. Incorporation and Corporate Power. BOKF is a corporation duly organized,
validly existing and in good standing under the laws of the state of Oklahoma.
BOKF has all the corporate power and authority necessary and required to
consummate the transactions contemplated by this Stock Purchase Agreement.

5.2. Non-Violation of Other Agreements. The execution and delivery of this Stock
Purchase Agreement, and compliance with its terms and provisions by BOKF and the
execution of any document required to be executed by BOKF, will not:

5.2.1. Violate, conflict with or result in the breach of their respective
certificates of incorporation or bylaws or any of the terms, conditions or
provisions of any agreement or instrument to which BOKF is a party, or by which
BOKF is bound;

5.2.2. Result in the creation or imposition of any lien, charge, encumbrance or
restriction of any nature whatever upon any of the property, contracts or
business of BOKF; or,

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5.2.3. Require the consent of any party to a contract with BOKF and in order to
keep the contract enforceable.

5.3. Required Corporate Action. The execution, delivery and consummation of this
Stock Purchase Agreement by BOKF has been duly and validly authorized by the
board of directors of BOKF. The approval of the shareholders of BOKF is not
required. This Stock Purchase Agreement has been duly executed and delivered by
duly authorized officers of BOKF. This Stock Purchase Agreement constitutes a
legal, valid and binding agreement and obligation of BOKF enforceable against
BOKF in accordance with its terms, except as may be limited by applicable
bankruptcy, insolvency, moratorium, receivership, and other similar laws
affecting the rights of creditors generally.

5.4. Brokerage Fees. BOKF has not incurred or will incur, directly or
indirectly, any liability for brokerage, finder's, financial advisor's or
agent's fees or commissions by virtue of any commitment made by BOKF in
connection with this Stock Purchase Agreement or any transaction contemplated
hereby. BOKF has no knowledge that any party has asserted any claim of such
nature against BOKF.

5.5. Survival and Independence of Representations and Warranties. The
representations and warranties of BOKF made in this Stock Purchase Agreement
shall not survive the Closing hereof. Each of the representations and warranties
of BOKF set forth in this Stock Purchase Agreement is a separate and independent
representation and warranty, shall be cumulative of and in addition to all other
warranties and representations; and shall not be interpreted to be in derogation
of any other representation or warranty or limit any other representation or
warranty made herein.

6. Covenants.

6.1. Full Access. In order that BOKF shall have the full opportunity to make
such investigations as it shall reasonably desire concerning Bank and UBC and
its business affairs, Bank and UBC shall:

6.1.1. Give BOKF, its employees, counsel, accountants and other authorized
representatives, as necessary to conduct the investigation, full access, upon
reasonable notice to Bank and UBC and at reasonable times without unduly
interfering with the conduct of business by Bank and UBC throughout the period
up to the Closing, to all of the facilities, properties, books, contracts and
records of Bank and UBC, including access to all meetings of the Bank's and
UBC's Board of Directors, committees or officers (except for the portions of
such meetings where this Agreement is discussed and where the presence of BOKF
representatives could operate as a waiver of the Bank's or UBC's attorney-client
privilege).

6.1.2. Authorize its accountants to give BOKF full access to the accountants'
records, including work papers; and,

6.1.3. Furnish to BOKF throughout the period up to the Closing all additional
financial, operating and other information concerning Bank and UBC and their
business affairs, as BOKF may reasonably request.

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6.1.4. Notify BOKF's representative, Stacy Kymes, within one business day of any
material changes, issues or claims which arise between the Effective Date of
this Agreement and Closing.

         All information provided pursuant to this Section 6.1 shall be subject
to the provisions of Section 6.5.

6.2. Conduct of Business Prior to the Closing Date. From this date until the
Closing Date, Bank and UBC shall, except as may be first approved in writing by
BOKF (such approval not to be unreasonably withheld, delayed or denied) or as is
otherwise permitted or contemplated in this Stock Purchase Agreement:

6.2.1. Maintain their corporate existence in good standing;

6.2.2. Maintain the general character of their business and conduct their
business in their ordinary and usual manner consistent with past practices;

6.2.3. Maintain proper business and accounting records generally in accordance
with past practices;

6.2.4. Maintain their properties (except repossessed and foreclosed assets
acquired in satisfaction of debts previously contracted) in normal repair and
condition, normal wear and tear and damage due to fire or other unavoidable
casualty excepted;

6.2.5. Preserve their business organizations intact, use their reasonable
efforts to maintain satisfactory relationships with suppliers, customers and
others having business relations with them whose relationships they believe are
desirable to maintain, and use their reasonable efforts to procure the
willingness of all of the personnel employed by them immediately prior to the
execution of this Stock Purchase Agreement who are material to the success of
their business to continue in their employ on substantially the same terms and
conditions as those on which such personnel were employed immediately prior to
the execution of this Stock Purchase Agreement except as otherwise agreed upon
by the parties; 6.2.6. Maintain the Insurance Policies in full force and effect
insurance and in comparable amount and scope of coverage to that now maintained
by them on the date hereof;

6.2.7. Except as otherwise disclosed in this Stock Purchase Agreement, perform
all of its obligations under all material contracts, leases and agreements
relating to or affecting their assets, properties and businesses;

6.2.8. Comply in all material respects with and perform all obligations and
duties imposed upon them by federal, state and local laws, and all rules,
regulations and orders imposed by federal, state or local governmental
authorities, except as may be contested by them in good faith by appropriate
proceedings.

6.2.9. UBC shall assign (or otherwise eliminate its obligation under) that
certain Promissory Note in the amount of $3,000,000 dated June 30, 2006 and
payable to United Christian Camps to BFP; and

 11

6.2.10. UBC shall distribute the Kickapoo Lodge, located on Kickapoo Lane, Grand
Lake, Colorado 80447, to BFP.

6.2.11. The Bank shall sell the residence located at 5388 Cloverbrook Circle,
Highlands Ranch, Colorado 80130 and currently occupied by John L. Kopecky for
not less than book value minus $25,000 (the "Minimum Sale Price"). In the event
the actual sale price is less than the Minimum Sale Price, the difference
between the Minimum Sale Price and the actual sale price, if any, (the "Home
Sale Loss") shall be deducted from the Cash Consideration at Closing.

6.3. Bank Prohibited Actions Prior to the Closing Date. From this date until the
Closing Date, Bank and UBC shall not, except as otherwise permitted by this
Stock Purchase Agreement or as requested or approved by BOKF in writing (which
approval shall not be unreasonably withheld, delayed or denied:

6.3.1. Incur any indebtedness for borrowed money or incur any noncurrent
indebtedness for the purchase price of any fixed or capital asset, or make any
extension of credit or any loans to, guarantee the obligations of, or make any
additional investments in, any other person, corporation or joint venture
(whether an existing customer or a new customer) except:

6.3.1.1 Extensions of credit, loans and guarantees less than fifty thousand
dollars ($50,000) per transaction; and

6.3.1.2 Borrowings from the Federal Home Loan Bank, the Federal Reserve Bank,
deposit liabilities, and federal funds transactions by Bank in the ordinary
course of business consistent with past practices.

6.3.2. Make any (a) material change in their assets (including, but not limited
to, any change in the composition of such assets so as to materially alter the
proportion of cash) or liabilities, (b) material commitment for any capital
expenditures (for purposes of this section, "material" shall mean capital
expenditures greater than $25,000), or (c) sale or other disposition of any
material capital asset;

6.3.3. Make any change in their Articles of Association, Articles of
Incorporation or Bylaws;

6.3.4. Authorize any shares of their capital stock for issuance, issue any
shares of any previously authorized but unissued capital stock or grant, issue
or make any option or commitment relating to their capital stock;

6.3.5. Enter into any letter of intent or agreement to sell any of their
material assets;

6.3.6. Declare or pay any dividend, make any other distribution or payment or
set aside any amount for payment with respect to any shares of their capital
stock or directly or indirectly, redeem, purchase or otherwise acquire any
shares of their capital stock or make any commitment relating thereto;

 12

6.3.7. Increase the compensation payable or to become payable to any of their
directors, officers or employees (including, without limitation, any bonus or
incentive payment or agreement), (b) make or enter into any written employment
contract or any bonus, stock option, profit sharing, pension, retirement or
other similar payment or arrangement, or (c) make any payment to any person,
except in the usual and ordinary course of business or except as required by an
existing agreement set forth in the Schedules hereto;

6.3.8. Make any material change in their banking, safe deposit or power of
attorney arrangements;

6.3.9. Enter into any trust, escrow, agency and similar trust company
agreements, purchase orders and contracts for goods and services, except in the
ordinary course of business consistent with past practices;

6.3.10. Enter into any agreement resulting in the imposition of any mortgage or
pledge of their assets or the creation of any lien, charge or encumbrance on any
of their assets;

6.3.11. Incur any material obligation or liability, absolute or contingent,
except in the ordinary course of business or pursuant to existing contracts
described in this Stock Purchase Agreement;

6.3.12. Take any action which would prevent compliance with any of the
conditions of this Stock Purchase Agreement; or,

6.3.13. Pre-pay long term indebtedness.

6.4. Regulatory Approval. BOKF shall (A) diligently file and pursue all
regulatory applications required in order to consummate the Transaction, the
merger of Bank into Colorado State Bank and Trust, NA, and for the approval to
operate the branch located at 6500 West 104th Avenue, Westminster, Colorado,
including but not limited to the necessary applications for prior approval of
the Board of Governors of the Federal Reserve System (the "Federal Reserve
Board") and the Office of the Comptroller of the Currency and (B) thereafter
promptly file any required supplements or amendments thereto, with the intent of
BOKF and BFP being to have the Closing within 30 days of the date of this
Agreement. All applications, supplements, and amendments shall be substantially
complete when filed. BOKF shall promptly deliver to UBC and its counsel a copy
of all such filings, as filed, except to the extent such filings attribute facts
or statements to Bank, in which case, such filings will be presented for review
and approval (which approval will not be unreasonably withheld, delayed or
denied) by Bank and counsel to Bank. Although all such filings shall be the
responsibility of BOKF, BOKF shall nevertheless advise and consult with UBC on
an ongoing basis with respect to the filings and all matters and events related
thereto. BOKF shall inform and make available to UBC from time to time all
matters relating to the filings and the regulatory approvals, including, without
limitation, copies of all written correspondence with regulatory authorities
relating to such matters. BOKF shall diligently proceed with reasonable
deliberate speed to obtain all such approvals. If any regulatory application
required to be filed by BOKF should be finally denied or disapproved by the
respective regulatory authority, then BOKF shall immediately give notice to UBC
and this Stock Purchase Agreement shall thereupon terminate. However, it is
understood that a request

 13

for additional  information or undertaking by the applicant,  as a condition for
approval,  shall  not be deemed  to be a denial  or  disapproval  so long as the
applicant can  reasonably be expected to provide the  requested  information  or
undertaking and so long as the undertaking  does not create a material change to
the nature of the transactions  contemplated by this Stock Purchase Agreement or
an undue burden,  as determined by BOKF, on post  Transaction  operations of the
Bank.  In the event an  application  is denied  pending an appeal,  petition for
review,  or similar such act on the part of the applicant,  then the application
will be deemed denied unless the applicant promptly and diligently  prepares and
files such  appeal and  continues  the  appellate  process  for the  purposes of
getting  the  necessary  approval,  such  process  to be  undertaken  at  BOKF's
discretion.

6.5. Confidentiality. Prior to the Closing, BOKF shall keep all information
disclosed or provided to BOKF (its employees, counsel, accountants, and other
authorized representatives) by UBC or Bank (or their representatives) respecting
the business and financial condition of UBC and Bank confidential and shall make
no use of such information except to conduct the investigation contemplated by
Section 6.1, the application contemplated by Section 6.4 and to consummate the
transactions contemplated hereby, and BOKF shall not use such information to
obtain a competitive advantage in connection with any customer of Bank. In the
event this Stock Purchase Agreement is terminated for any reason BOKF (its
agents, officers, directors, employees and counsel) shall (A) return all copies
of all information and documents obtained from UBC, Bank, and their
representatives, (B) thereafter keep all such information confidential and not
make use of any such information to obtain a competitive advantage in connection
with any customer of Bank, and (C) shall not solicit for employment, whether
directly or indirectly, any of the employees, officers or directors of UBC or
Bank for a period of one year following such termination; provided however,
general solicitations in the media shall not constitute a solicitation
prohibited by this section.

6.6. Disclosure. Neither BOKF nor UBC, nor any other party to this Stock
Purchase Agreement or their representative, shall make any public disclosure
concerning this Stock Purchase Agreement or the Transaction contemplated herein
without the mutual consent of each of the other parties hereto to the timing and
content of the disclosure; provided, however, (A) the parties hereto may make
any disclosure (i) necessary to maintain compliance with applicable federal or
state laws or regulations after providing such disclosure to the other party or
(ii) required in connection with the making of any application necessary to
effect the Transaction; and (B) that the Carson Medlin Company shall be
permitted to publish a "tombstone" advertisement subsequent to the signing of
this Agreement.

6.7. BOKF Prohibited Action Prior to Closing. From this date until the Closing
Date, BOKF shall not take any action which would prevent compliance with any of
the conditions of this Stock Purchase Agreement. BOKF shall not, and shall cause
its subsidiaries not to, make or agree to make any acquisition, or take any
other action, that adversely affects its ability to consummate the transactions
contemplated by this Stock Purchase Agreement and will otherwise continue to
conduct its business operations and shall cause the operations of its
subsidiaries to be conducted in a manner consistent with past operating
practices.

6.8. No Solicitation. From the date of this Agreement until 45 days thereafter,
unless this Stock Purchase Agreement is sooner terminated, neither Bank nor UBC
shall directly or

 14

indirectly  (i) solicit or encourage  inquiries or proposals with respect to the
merger  of UBC or the  Bank or the sale of any of the  shares  of Bank or UBC or
other  material  asset(s)  of UBC or Bank from any party other than BOKF or (ii)
merge  with any party or sell all or  substantially  all of the shares of UBC or
Bank or all or  substantially  all the  material  asset(s) of UBC or Bank to any
party.

6.9. BOKF and Transaction Corp Indemnification. BOKF shall indemnify the present
and future directors, officers and employees of Bank (the "Indemnified Parties")
to the fullest extent to which such Indemnified Parties were entitled under the
Articles of Association, Articles of Incorporation and Bylaws of Bank and UBC as
in effect as of the date hereof; provided, however, that the foregoing
indemnification shall not apply in the event of a breach by Bank, UBC or BFP of
the representations, warranties or covenants provided herein.

6.10. Insurance and Personal Property. For a period of two years after Closing,
BOKF shall provide health insurance for Stephen Baltz, Martha Baltz and Kimberly
Baltz. On the Closing Date, BOKF shall transfer to Stephen Baltz the Bank-owned
automobile and computer that he currently is using and shall transfer to Marty
Baltz and Kimberly Baltz the Bank-owned computers they are using. If, within two
years after the Closing, BOKF shall cease to display the artwork set forth on
Schedule 6.10, then BOKF shall give Stephen Baltz the right to purchase such
artwork at its book value as of the date of this Agreement as set forth on
Schedule 6.10. BOKF agrees that the following accounts at Bank may be
transferred to BFP prior to Closing so long as the total balance of the three
accounts does not exceed $200,000: United Banks of Colorado, Kickapoo Lodge
account 4080-004-973; First United Bancorporation, General Operating Account,
1943-1130-7251; and United Banks of Colorado, Money Market Account,
2080-001-124.

6.11. Indemnification. As to unasserted claims that arise after the Closing Date
for actions that occurred prior to the Closing Date, until such time as such
claim is barred by its applicable statute of limitations or any until litigation
is completed, and as to commenced litigation, for such time period until
litigation is completed, BFP shall indemnify and hold BOKF, its affiliates
(including but not limited to, Colorado State Bank and Trust, NA), officers,
directors, employees, shareholders, agents, successors and assigns ("BOKF
Indemnified Parties") harmless from and against any and all claims against, or
costs incurred by (including reasonable attorneys' fees and cost of experts) the
BOKF Indemnified Parties related to claims disclosed (both current and potential
claims) by UBC or Bank pursuant to only those claims set forth under Schedule
4.10 of this Agreement; provided, however BFP shall not indemnify the BOKF
Indemnified Parties for actions of the BOKF Indemnified Parties after the
Closing Date.

6.12. Net Worth Maintenance. BFP agrees for a period of one year following
Closing to maintain a net worth of not less than Fifteen Million Dollars
($15,000,000) (the "First Maintenance Year") and thereafter to maintain a net
worth of not less than Ten Million Dollars ($10,000,000) until the second
anniversary of the Closing (the "Second Maintenance Year"). During the First
Maintenance year, Five Million Dollars ($5,000,000) of the total Fifteen Million
Dollar ($15,000,000) net worth requirement must consist of assets which may be
liquidated within three (3) months. During the Second Maintenance Year, Two
Million Five Hundred Thousand Dollars ($2,500,000) of the Ten Million Dollar
($10,000,000) net worth requirement must consist of assets which may be
liquidated within three (3) months. BFP shall provide

 15

BOKF written evidence reasonably  acceptable to BOKF of its compliance with this
Section 6.12 on a quarterly basis.

7. Conditions Precedent to Closing by BOKF. The obligation of BOKF to consummate
and close this transaction is conditioned upon each and all of the following:

7.1. The representations, warranties and covenants of BFP, UBC and Bank shall be
materially true at the Closing as though such representations, warranties and
covenants were also made at the Closing.

7.2. The Federal Reserve Board shall have approved the Transaction, or issued a
waiver of approval, in accordance with 12 U.S.C. Section 1842 and 12 C.F.R.
Section 225 and Section 6.4 herein.

7.3. The Office of the Comptroller of the Currency ("OCC") shall have, as
provided in Section 6.4 herein, (i) approved the Transaction in accordance with
the National Bank Act and (ii) approved the merger of Bank into Colorado State
Bank and Trust, NA and (iii) approved the branch application for the 6500 West
104th Avenue, Westminster, Colorado.

7.4. BFP, UBC and Bank shall have performed and complied with, in all material
respects, all of their obligations under this Stock Purchase Agreement which are
to be performed or complied with by them prior to or on the Closing Date.

7.5. BFP shall have approved this Stock Purchase Agreement in accordance with
the Colorado Business Corporation Act and the banking laws of the United States.
The BFP Partners shall have approved this Stock Purchase Agreement in accordance
with the Colorado Limited Partnership Association Act.

7.6. Since the date of this Agreement, Bank has not suffered any Material
Adverse Change (as hereinafter defined) in its financial conditions, assets,
liabilities, businesses or properties. For purposes of this Section 7.6,
"Material Adverse Change" shall mean any event which has a negative financial
impact on UBC or the Bank of Five Hundred Thousand Dollars ($500,000) or more;
provided, however, assuming that none of the following impact UBC and Bank more
than similarly situated banks and bank holding companies, a "Material Adverse
Change" will not result from (i) change in banking and similar laws and
regulations, (ii) changes in interest rates or (iii) any decline in general
economic conditions nationally.

7.7. Bank shall have received its annual audit for the year ended December 31,
2006 from BKD and such audit report shall be acceptable to BOKF in all material
respects and shall be consistent, in all material respects, with financial
information previously provided to BOKF.

         7.8......BOKF shall have received title opinions that either Bank or
UBC have full and valid title to all Bank locations without lien or encumbrance
other than standard public right of way.

         BOKF shall be entitled to waive compliance by UBC, BFP or Bank with any
one or more of the conditions, representations, warranties or covenants in whole
or in part. In the event any one or more of these conditions shall not have been
fulfilled prior to or at the Closing, BOKF

 16

may terminate  this Stock  Purchase  Agreement by written notice to UBC, BFP and
Bank,  in which  event  neither  party  shall  have any  further  obligation  or
liability to the other except the  obligations of BOKF set forth in Sections 5.4
and 6.5 and the  obligations  of UBC and Bank set forth in  Section  4.11.  BOKF
shall be entitled to waive  compliance  with any one or more of the  conditions,
representations, warranties or covenants in whole or in part.

8. Conditions Precedent to Closing by UBC and Bank. The obligation of BFP, UBC
and Bank to consummate and close this transaction are conditioned upon each and
all of the following:

8.1. The representations, warranties and covenants of BOKF made in this Stock
Purchase Agreement shall be true at the Closing as though such representations,
warranties and covenants were also made at the Closing.

8.2. BOKF shall have performed and complied, in all material respects, with all
of their obligations under this Stock Purchase Agreement which are to be
performed or complied with by them prior to or at the Closing.

8.3. The Federal Reserve Board shall have approved the Transaction, or issued a
waiver of approval, in accordance with 12 U.S.C. Section 1842 and 12 C.F.R.
Section 225.

8.4. UBC shall be entitled to waive BOKF's compliance with any one or more of
the conditions, representations, warranties or covenants-in whole or in part. In
the event any one or more of these conditions shall not have been fulfilled
prior to or at the Closing, UBC may terminate this Stock Purchase Agreement by
notice to BOKF, in which event no party shall have any further obligation or
liability to the other, except the obligations of BOKF set forth in Section 6.5
and Section 5.4 and the obligations of UBC set forth in Section 4.11.

8.5. Within fifteen (15) calendar days of the date of this Agreement, UBC shall
have received an opinion from the Carson Medlin Company in form and substance
satisfactory to UBC to the effect that on the basis of certain facts,
representations and opinions set forth in such opinion that the Transaction
Consideration is fair from a financial point of view to the shareholders of UBC.

9. Closing. The closing ("Closing" or "Closing Date") of the transactions
contemplated by this Stock Purchase Agreement shall take place not later than
three (3) business days following the first day on which (i) BOKF can lawfully
consummate the Transaction under 12 U.S.C. Section 1842, 12 C.F.R. Section 225
and other applicable laws, rules and regulations and (ii) all conditions
precedent to the obligations of the parties set forth in Section 7 and Section 8
have been satisfied or waived. The Parties shall use their best efforts to cause
the Closing to occur within sixty (60) days of the Effective Date of this
Agreement. In any event, if the Closing Date does not occur on or before July
15, 2007, then either BOKF or BFP may by notice to the other, terminate this
Stock Purchase Agreement, provided that the delay in closing was not caused by
the actions (or inactions) of the party attempting to terminate the Agreement
under this Section 9. The Closing shall be held at 10:00 a.m. on the Closing
Date at the offices of Bank or at such other time and place as BOKF and Bank may
agree. At the Closing, BOKF, BFP, UBC, and

 17

Bank shall  execute and deliver all of the  documents and take all other actions
which are contemplated by the terms hereof.

9.1. Without limiting the generality of Section 9 of this Stock Purchase
Agreement, the following actions shall be taken at the Closing concurrently.
BFP, UBC and Bank shall:

9.1.1. Deliver certificates, signed by the Chief Executive Officers and the
Chief Financial Officers of UBC and of the Bank and the general partner of BFP
stating, respectively, that (A) the representations and warranties of BFP, UBC
and the Bank, as set forth herein are true and correct in all material respects
at the time of the Closing with the same force and effect as if such
representations and warranties had been made at Closing and (B) all of the
conditions precedent to the obligation of BOKF to close set forth in this
Agreement have, unless waived as herein provided, been satisfied;

9.1.2. Deliver a certified copy of the resolutions of the Board of Directors and
shareholder of Bank and UBC as required for valid approval of the execution of
this Agreement and the consummation of the Transaction and the other
transactions contemplated hereby;

9.1.3. Deliver good standing and existence certificates, dated a recent date,
duly certifying the existence and good standing of the Bank and UBC;

9.1.4. Deliver a resolution of the Board of Directors of Bank approving the
merger of the Bank 401(k) plan into the defined contribution plan of BOKF.

9.1.5. Cause the employment agreements, plans and payments described in Schedule
4.15 to be terminated and discharged at no cost to Bank.

9.1.6. Deliver certificates evidencing all UBC Common Stock duly endorsed for
transfer or accompanied by appropriate stock transfer powers duly executed in
blank, in either case with signatures guaranteed in the customary fashion, and
shall have all the necessary documentary transfer tax stamps affixed thereto at
the expense of the UBC.

9.2. Without limiting the generality of Section 9 of this Stock Purchase
Agreement, the following actions shall be taken at the Closing concurrently.
BOKF shall:

9.2.1. Deliver by wire transfer the Closing Amount to a bank account designated
by BFP at least five business days prior to Closing;

9.2.2. Deliver by wire transfer the Escrow Amounts to the Escrow Agent; and,

9.2.3. Deliver certificates, signed by the Chief Executive Officers and the
Chief Financial Officers of BOKF, that (A) the representations and warranties of
BOKF, as set forth herein are true and correct in all material respects at the
time of the Closing with the same force and effect as if such representations
and warranties had been made at Closing and (B) all of the conditions precedent
to the obligation of BOKF to close set forth in this Agreement have, unless
waived as herein provided, been satisfied.

 18

10. The General Escrow. The General Escrow shall be established on the following
terms and conditions:

10.1. The escrow agent shall be Bank of Oklahoma, National Association ("Escrow
Agent" or "BOk").

10.2. The General Escrow shall be governed by the standard form Escrow Agreement
(the "Escrow Agreement") a copy of which is set forth as Schedule 10.2.

10.3. BOKF shall deliver the General Escrow Amount to the Escrow Agent at the
Closing. The Escrow Agent shall invest the General Escrow Amount in an interest
bearing account that bears interest equal to that of a twenty four month
certificate of deposit issued by BOk on the terms and conditions being offered
by BOk to the public at the time of such investment. Interest on the
certificates shall be added to the General Escrow and distributed to BFP on a
quarterly basis.

10.4. In the event BOKF claims a breach of the representations and warranties of
UBC and Bank arising under this Stock Purchase Agreement prior to the second
anniversary of the Closing Date (the "Claim Notice Deadline"), BOKF shall give
written notice of the claim (a "Claim") to Stephen P. Baltz, or his successor as
agent for BFP (the "Agent"). The notice shall identify the representations and
warranties which BOKF claims have been breached and describe in reasonable
detail the basis of the Claim and set forth a good faith reasonable estimate
("Good Faith Estimate") of the maximum amount of damages claimed ("Losses"). The
Agent shall have five (5) business days to challenge the validity of any Claim
by providing written notice of such dispute to BOKF and the Escrow Agent. The
Escrow Agent shall not pay any disputed Claim until such dispute is resolved as
provided for in Section 10.7 of the Agreement.

10.5. BOKF shall make no Claim unless and until the aggregate amount of all
uninsured Losses shall exceed two hundred thousand dollars ($200,000) (the
"Escrow Threshold"), in which event BOKF may make Claims against the Escrow for
all Losses (including, but not limited to, those Losses which caused Losses to
exceed the Escrow Threshold).

10.6. In the event BOKF makes no Claim for any Losses on or before the Claim
Notice Deadline, the Escrow Agreement shall terminate and the Escrow Agent
shall, within five (5) business days thereafter, distribute the Escrow Amount to
BFP.

10.7. In the event BOKF makes one or more Claim(s) prior to the Claim Notice
Deadline, the Escrow Agent shall (i) on or before five (5) business days after
the Claim Notice Deadline, distribute to BFP the Escrow Amount less the amount
of all Losses claimed by BOKF for distribution in accordance with Section 10.8
hereof, and (ii) continue to hold and invest the remaining Escrow Amount until
such claim is resolved by (1) mutual agreement of the Agent and BOKF, or (2) a
final adjudication determining the merits of the BOKF Claim, at which time the
Escrow Agreement shall terminate, the Escrow Agent shall pay the claim of BOKF
as mutually agreed or finally adjudicated and the Escrow Agent shall distribute
any remaining Escrow Amount to the Paying Agent for distribution in accordance
with Section 10.8 hereof.

 19

10.8. Upon termination of the Escrow, the Escrow Amount remaining in the Escrow
shall be delivered to BFP.

10.9. The rights of BFP to receive payments from the Escrow shall not be
assignable or transferable except by operation of law or by intestacy or with
the approval of BOKF (which approval shall not be unreasonably withheld,
delayed, or denied) and will not be evidenced by any certificate or other
evidence of ownership.

10.10. BOKF shall pay the fees and costs of the Escrow Agent with respect to the
Escrow.

10.11. BFP may, upon notice to BOKF, change the Agent. The Agent shall not be
deemed a fiduciary of BFP and shall be liable to BFP only for gross negligence
or intentional wrongdoing.

10.12. BOKF agrees it shall diligently defend any litigation in good faith in
the same manner it would in the event the General Escrow Amount did not exist.
BOKF will not settle any claim without the prior written consent of the Agent,
which consent shall not be unreasonably withheld. BOKF shall consult with Agent
and his counsel at reasonable intervals regarding all litigation matters.

11. Loan Escrow. The Loan Escrow shall be established on the following terms and
conditions:

11.1. The escrow agent shall be the Escrow Agent.

11.2. The escrow agreement shall be in the form of the Escrow Agreement.

11.3. BOKF shall pay the Loan Escrow Amount into the Loan Escrow as the original
amount thereof.

11.4. The Loan Escrow shall be invested in the manner set forth in Section 10.3
with interest on the Loan Escrow Amount distributed quarterly to BFP.

11.5. BOKF shall cause Bank (or its successor) to use its best efforts to
collect or make recovery on all loans, credits or advances that were made by the
Bank on or prior to Closing (collectively, "Loans" or individually "Loan", all
of which have been set forth on Schedule 11.5); the Bank (or its successor)
shall keep the Agent reasonably informed of its collection efforts.

11.6. Seller shall pay all of the reasonable, out-of-pocket collection costs in
excess of $50,000 out of the Loan Escrow.

11.7. In the event of a loss of principal, interest accrued from and after
Closing and/or collection costs (which costs shall not include the personnel
costs of BOKF or its affiliates) incurred from and after Closing is incurred on
a Loan (a "Loan Loss"), the Loan Loss shall be paid to Bank out of all funds
held in the Loan Escrow (whether loss of principal, interest, or inability to
recover the costs of collection); provided, however, before Bank (or its
successor) places a Loan on nonaccrual status, BOKF shall give BFP the
opportunity to buy the Loan in

 20

question for the amount of the Loan Loss by giving Agent ten (10)  business days
notice of Bank's  intent to charge a Loan Loss to the Loan Escrow.  Upon payment
of a Loan Loss by BFP, Bank shall  promptly  transfer and assign all rights with
respect to the Loan  incurring the Loan Loss to BFP,  which shall be entitled to
recover and collect any and all  outstanding  amounts owing on such Loan for its
own account. All recoveries of principal and/or interest on Loan Losses received
by Bank (or its successor) shall be added back to the Loan Escrow.  BOKF and BFP
agree  that,  in the  event  payment  is  made  on any of the  nonaccrual  loans
identified on Schedule  11.7,  such payment shall be attributed as follows:  (a)
first,  to  outstanding  principal  for the benefit for BOKF until all principal
amounts have been paid in full and (b) second, to unaccrued interest which shall
be divided on a pro-rata basis between  interest that was owed on or before June
15, 2007 ("BFP  Interest") and interest that was owed after June 15, 2007 ("BOKF
Interest").  Any and all BFP Interest shall be (a) added to the Loan Escrow, (b)
subject  to all  claims  of  Loan  Loss by BOKF  and (c)  distributed  to BFP in
accordance  with Section 11.8. All BOKF Interest shall be solely for the benefit
of BOKF.

11.8. At such time as further collection efforts in respect of a Loan are
determined, in BOKF's reasonable judgment, to be unwarranted, the amount of the
Loan Loss in respect of the Credit shall be paid to the Bank out of the Loan
Escrow. On the earlier of (i) the third anniversary of the Closing or (ii) such
time as the Loans (a) have been paid with no Loan Loss and (b) all Loan Loss
shall have been paid to the Bank out of the Loan Escrow then the balance in the
Loan Escrow remaining after payment of any and all Loan Loss to the Bank shall
be paid to BFP and the Loan Escrow shall be closed; provided however, BOKF
agrees that prior to the second anniversary of the Closing, BOKF shall review
the remaining Loans in good faith and provide Agent a list of Loans which it
reasonably believes may result in a Loan Loss (the "Remaining Loans"). Agent
shall then have a thirty (30) day option to purchase the Remaining Loans for
cash in an amount equal to the remaining principal balance and accrued interest
on the Remaining Loans (the "Purchase Option"). In the event Agent does not
exercise the Purchase Option, the Loan Escrow shall remain in effect until the
third anniversary of the Closing.

12. Break-Up Fee. UBC shall pay BOKF a break-up fee as follows:

12.1. For a period of forty five days after the date of this Agreement, and in
the event BOKF is not in default of any material obligation of BOKF under this
Agreement and the Transaction is not consummated because the Board of Directors
of Bank or UBC and/or shareholders of Bank or UBC approve an alternative
transaction (whether or not submitted by the Board of Directors to the UBC
shareholders for approval and whether or not such alternative transaction is
consummated) then, Bank or UBC shall pay BOKF in United States funds immediately
available in Tulsa, Oklahoma, on or before the fifth Tulsa business day
following the date on which the Board of Directors and/or shareholders of UBC
and/or Bank approve such an alternative proposal, Two Million Dollars
($2,000,000).

12.2. UBC agrees that (A) the damages incurred by BOKF in any such event would
be substantial, but (B) such damages could be difficult to quantify; and
accordingly, (C) such amount constitutes a reasonable estimate of such damages.

13. Miscellaneous Provisions. The following miscellaneous provisions shall apply
to this Agreement:

 21

13.1. All notices or advices required or permitted to be given by or pursuant to
this Agreement, shall be given in writing. All such notices and advices shall be
(i) delivered personally, (ii) delivered by facsimile (iii) delivered by email
(iv) delivered by U.S. Registered or Certified Mail, Return Receipt Requested
mail, or (v) delivered for overnight delivery by a nationally recognized
overnight courier service. Such notices and advices shall be deemed to have been
given (i) the first business day following the date of delivery if delivered
personally, by facsimile or by email, (ii) on the third business day following
the date of mailing if mailed by U.S. Registered or Certified Mail, Return
Receipt Requested, or (iii) on the date of receipt if delivered for overnight
delivery by a nationally recognized overnight courier service. All such notices
and advices and all other communications related to this Agreement shall be
given as follows:

         BOKF and Transaction Corp:

                  Steven E. Nell, Chief Financial Officer
                  BOK FINANCIAL CORPORATION
                  P.O. Box 2300
                  Tulsa, OK 74192
                  (918) 588-6853 - Facsimile
                  Snell@bokf.com


         And

                  Frederic Dorwart, Secretary and General Counsel to
                  BOK Financial Corporation
                  Old City Hall
                  124 East Fourth Street
                  Tulsa, OK 74103
                  (918) 583-8251 - Facsimile
                  fdorwart@fdlaw.com


         UBC:

                  Stephen P. Baltz
                  United Banks of Colorado Inc.
                  8095 E. Belleview Avenue
                  Englewood, Colorado  80111
                  (303) 741-5825 - Facsimile
                  spbaltz@1stunited bank.com
                  --------------------------


         Bank:

                  Stephen P. Baltz
                  First United Bank, N.A.
                  8095 E. Belleview Avenue

 22

                  Englewood, Colorado  80111
                  (303) 741-5825 - Facsimile
                  spbaltz@1stunitedbank.com
                  -------------------------


         BFP:

                  Stephen P. Baltz
                  Baltz Family Partners, Ltd.
                  P.O. Box 4772 Parker, Colorado 80134
                   (303) 741-5825 - Facsimile
                  spbaltz@hotmail.com



         With a copy to:

                  Sanford M. Brown
                  Bracewell & Giuliani LLP
                  1445 Ross Avenue, Suite 3800
                  Dallas, Texas  75201
                  (214) 758-8300 - Facsimile
                  sanford.brown@bgllp.com
                  -----------------------

or to such other address as the party may have furnished to the other parties in
accordance herewith, except that notice of change of addresses shall be
effective only upon receipt.

13.2. This Agreement shall be subject to, and interpreted by and in accordance
with, the laws (excluding conflict of law provisions) of the State of Oklahoma;
venue for any disputes arising under this Agreement shall be in the state and
federal courts in Tulsa, Oklahoma.

13.3. This Agreement is the entire agreement of the parties respecting the
subject matter hereof. There are no other agreements, representations or
warranties, whether oral or written, respecting the subject matter hereof.

13.4. No course of prior dealings involving any of the parties hereto and no
usage of trade shall be relevant or advisable to interpret, supplement, explain
or vary any of the terms of this Agreement, except as expressly provided herein.

13.5. This Agreement, and all the provisions of this Agreement, shall be deemed
drafted by all of the parties hereto.

13.6. This Agreement shall not be interpreted strictly for or against any party,
but solely in accordance with the fair meaning of the provisions hereof to
effectuate the purposes and interest of this Agreement.

 23

13.7. Each party hereto has entered into this Agreement based solely upon the
agreements, representations and warranties expressly set forth herein and upon
his own knowledge and investigation. Neither party has relied upon any
representation or warranty of any other party hereto except any such
representations or warranties as are expressly set forth herein.

13.8. Each of the persons signing below on behalf of a party hereto represents
and warrants that he or she has full requisite power and authority to execute
and deliver this Agreement on behalf of the parties for whom he or she is
signing and to bind such party to the terms and conditions of this Agreement.

13.9. This Agreement may be executed in counterparts, each of which shall be
deemed an original. This Agreement shall become effective only when all of the
parties hereto shall have executed the original or counterpart hereof. This
agreement may be executed and delivered by a facsimile transmission of a
counterpart signature page hereof.

13.10. In any action brought by a party hereto to enforce the obligations of any
other party hereto, the prevailing party shall be entitled to collect from the
opposing party to such action such party's reasonable litigation costs and
attorneys fees and expenses (including court costs, reasonable fees of
accountants and experts, and other expenses incidental to the litigation).

13.11. This Agreement shall be binding upon and shall inure to the benefit of
the parties and their respective successors and assigns.

13.12. This is not a third party beneficiary contract except as otherwise
expressly stated herein. No person or entity other than a party signing this
Agreement shall have any rights under this Agreement except as otherwise
expressly stated herein.

13.13. This Agreement may be amended or modified only in a writing which
specifically references this Agreement.

13.14. This Agreement may not be assigned by any party hereto.

13.15. A party to this Agreement may decide or fail to require full or timely
performance of any obligation arising under this Agreement. The decision or
failure of a party hereto to require full or timely performance of any
obligation arising under this Agreement (whether on a single occasion or on
multiple occasions) shall not be deemed a waiver of any such obligation. No such
decisions or failures shall give rise to any claim of estoppel, laches, course
of dealing, amendment of this Agreement by course of dealing, or other defense
of any nature to any obligation arising hereunder.

13.16. The repudiation, breach, or failure to perform any obligation arising
under this Agreement by a party after reasonable notice thereof shall be deemed
a repudiation, breach, and failure to perform all of such party's obligations
arising under this Agreement.

13.17. Time is of the essence with respect to each obligation arising under this
Agreement. The failure to timely perform an obligation arising hereunder shall
be deemed a failure to perform the obligation.

 24

13.18. All actions taken and documents delivered at the Closing shall be deemed
to have been taken and executed simultaneously and no action shall be deemed
taken nor any document delivered until all have been taken and delivered.

13.19. Any information delivered by way of Schedule or schedule in connection
with this agreement shall be deemed delivered for the purpose of any other
Schedule or schedule which calls for such information.

13.20. In the event of a breach of an obligation to pay under this Stock
Purchase Agreement, the breaching party agrees to pay the non-breaching party
interest on the unpaid amount beginning on the date of default at a per annum
rate of U.S. National Prime plus two percent (2%), compounded annually.



                        [SPACE INTENTIONALLY LEFT BLANK]





Dated and effective the date first set forth above.

BOK FINANCIAL CORPORATION                     BALTZ FAMILY PARTNERS, LTD.

By: /s/ Steven E. Nell                        By: /s/  Stephen P. Baltz
    ------------------                                 ---------------------
    Steven E. Nell, Chief Financial Officer   Stephen P. Baltz, General Partner


FIRST UNITED BANK, N.A.                       UNITED BANKS OF COLORADO, INC.

By:  /s/  Stephen P. Baltz                    By:    /s/  Stephen P. Baltz
     ---------------------                           ---------------------
     Stephen P. Baltz, President              Stephen P. Baltz, President