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                                   EXHIBIT 10

                        THIRD AMENDMENT TO LOAN AGREEMENT

     THIS THIRD AMENDMENT ("Third Amendment") dated as of the 15th day of
September, 2003, to the Loan Agreement (the "Loan Agreement"), made and entered
into as of September 15, 2001, by and among SUMMIT BANCSHARES, INC., a Texas
corporation, (hereinafter called "Borrower"), SUMMIT DELAWARE FINANCIAL
CORPORATION, a Delaware corporation, (hereinafter called "SDFC") and THE FROST
NATIONAL BANK, a national banking association (hereinafter called "Lender"). All
capitalized terms not otherwise defined herein shall have the meaning ascribed
to each of them in the Loan Agreement.

                                   WITNESSETH:

     WHEREAS, Borrower executed the Loan Agreement to govern those two certain
promissory notes from Lender, specifically, a $10,000,000.00 Acquisition Note
and a $1,000,000.00 Liquidity Note (collectively, the "Notes").

     WHEREAS, Borrower executed the First Amendment to Loan Agreement on March
8, 2002 ("First Amendment") which modified the Loan Agreement to evidence the
Borrower's formation of SDFC to own the Bank;

     WHEREAS, Borrower executed that certain Second Amendment to Loan Agreement
dated September 15, 2002 ("Second Amendment") which renewed and extended the
maturity date of the Notes;

     WHEREAS, the Borrower now desires to further renew and extend the unpaid
principal balance of the Notes; and

     WHEREAS, the Lender agrees to renew and extend the Notes all as hereinafter
provided.

     NOW, THEREFORE, in consideration of the premises and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, Borrower and Lender do hereby agree as follows:

                                    ARTICLE I

                           Amendment to Loan Agreement

     1.1 Amendment to Notes. As of the effective date hereof, the Borrower has
zero outstanding under the Acquisition Note and the Liquidity Note. The Borrower
desires to renew these credit facilities by the execution of another Acquisition
Note and Liquidity Note extending the original payment terms and the maturity
date by one year. Accordingly, Sections 2.02 (a) and (b) of the Loan Agreement
shall be, and are hereby, amended to read in their entirety as follows:

          "2.02 (a) Acquisition Note. From Closing Date and continuing
     at all times through September 15, 2004 (the "Revolving Credit Period") the
     Loan evidenced by the Acquisition Note shall be a revolving credit facility
     which will allow the Borrower to request such amounts as Borrower may elect
     from time to time (each such amount being herein called an "Advance") so
     long as the aggregate amount of Advances outstanding at any time under the
     Acquisition Note does not exceed Ten Million and NO/100 Dollars
     ($10,000,000.00) provided however, the minimum Advance must be at least
     $500,000.00. The Borrower shall have the right to borrow, repay, and borrow
     again under the credit facility. Interest shall be due and payable
     quarterly and shall accrue at the election of the Borrower (which election
     shall be made at the date of the first Advance) at either LIBOR plus 200
     basis points or the Prime Rate. The outstanding principal balance at the
     Acquisition Note on September 15, 2004 shall convert to a term facility
     (the "Term Period") and shall be payable in accordance with the terms of
     the Acquisition Note.

          (b)  Liquidity Note. The Liquidity Note shall be due and
     payable as follows: during the Revolving Credit Period, the Loan evidenced
     by the Liquidity Note shall be a revolving credit facility which will allow
     the Borrower to request such amounts as Borrower may elect from time to
     time (each such amount being herein called an "Advance") so long as the
     aggregate amount of Advances outstanding at any time under the Liquidity
     Note does not exceed One Million and NO/100 Dollars ($1,000,000.00)
     provided however, the minimum Advance must be at least $50,000.00. The
     Borrower shall have the right to borrow, repay, and borrow again under the
     credit facility. Interest shall be due and payable quarterly and shall
     accrue at the Prime Rate. The outstanding principal balance of the
     Liquidity Note on September 15, 2004 shall convert to a term facility (the
     "Term Period") and shall be payable in accordance with the terms of the
     Liquidity Note.


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     1.1 Amendment to Financial Covenants. In connection with the renewal of the
Notes, the Borrower and Lender desire to amend certain financial covenants
contained in the Loan Agreement. Accordingly, Sections 5.04, 5.08 and 5.11 of
the Loan Agreement shall be, and are hereby, amended to read in their entirety
as follows:

     "5.04 Tangible Net Worth. The Borrower shall not permit its consolidated
Tangible Net Worth to at any time be less than Fifty-Five Million and no/100
Dollars ($55,000,000.00)."

     "5.08 Dividends. Borrower shall not declare or pay any dividends, make any
payment on account of any class of the capital stock of Borrower now or
hereinafter outstanding, or make any distribution of cash or property to holders
of any shares of such stock which exceed Five Million Dollars ($5,000,000.00) in
the aggregate during any fiscal year, provided however, without Lender's prior
written consent, Borrower will not declare any dividend so long as Borrower is
in default in payment of the Obligations. Payment by Borrower for shares
purchased under a stock repurchase play by which Borrower purchases its own
shares on the open market will not be considered a distribution to
shareholders."

     "5.11 Limitation on Debt. Borrower shall not, nor allow any Subsidiary to,
create, incur, assume, become liable in any manner in respect of, or suffer to
exist, any debt for borrowed money except:

          (a)  debt, excluding debt created under this Agreement, not
     in excess of $1,000,000.00 at any one time outstanding;

          (b)  debt created under this Agreement;

          (c)  debt secured by a purchase money security interest; and

          (d)  $25,000,000.00 of federal funds purchased; and

          (e)  any borrowings from the Federal Home Loan Bank which shall not
     exceed $75,000,000.00

                                   ARTICLE II

                           Conditions of Effectiveness

     2.1 Effective Date. This Third Amendment shall become effective as and
when, and only when, Lender shall have received counterparts of this Third
Amendment executed and delivered by Borrower and when each of the following
conditions shall have been met, all in form, substance, and date satisfactory to
Lender:

          (a)  Renewal Notes. Borrower shall have executed and
     delivered to Lender a new Acquisition Note and new Liquidity Note, each
     payable to the order of Lender as set forth therein, each duly executed on
     behalf of the Borrower, dated effective September 15, 2003 in the principal
     amounts of $10,000,000.00 and $1,000,000.00, respectively.

          (b)  Additional Loan Documents. Borrower and SDFC shall have
     executed and delivered to Lender such other documents as shall have been
     requested by Lender to secure payment of the Obligations of Borrower, all
     in form satisfactory to Lender and its counsel.

                                   ARTICLE III

                         Representations and Warranties

     3.1 Representations and Warranties of the Borrower. In order to induce
Lender to enter into this Third Amendment, Borrower represents and warrants the
following:

          (a)  Borrower has the corporate power to execute and deliver
     this Third Amendment and the other Loan Documents executed by it and to
     perform all of its obligations in connection herewith and therewith.

          (b)  The execution and delivery by Borrower of this Third
     Amendment and other Loan Documents executed by it and the performance of
     its obligations in connection herewith and therewith: (i) have been duly
     authorized or will be duly ratified and affirmed by all requisite corporate
     action; (ii) will not violate any provision of



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     law, any order of any court or agency of government or the Articles of
     Incorporation or Bylaws of such entity; (iii) will not be in conflict with,
     result in a breach of or constitute (alone or with due notice or lapse of
     time or both) a default under any indenture, agreement or other instrument;
     and (iv) will not require any registration with, consent or approval of or
     other action by any federal, state, provincial or other governmental
     authority or regulatory body.

                     (c) There is no action, suit or proceeding at law or in
           equity or by or before any governmental instrumentality or other
           agency or regulatory authority now pending or, to the knowledge of
           Borrower, threatened against or affecting Borrower or any properties
           or rights of Borrower or involving this Third Amendment or the
           transactions contemplated hereby which, if adversely determined,
           would materially impair the right of Borrower, to carry on business
           substantially as now conducted or materially and adversely affect the
           financial condition of Borrower or materially and adversely affect
           the ability of Borrower to consummate the transactions contemplated
           by this Third Amendment.

                     (d) The representations and warranties of Borrower
           contained in the Loan Agreement, this Third Amendment and any other
           Loan Document securing Borrower's Obligations and indebtedness to
           Lender are correct and accurate on and as of the date hereof as
           though made on and as of the date hereof, except to the extent that
           the facts upon which such representations are based have been changed
           by the transactions herein contemplated.

           3.2 Representations and Warranties of SDFC. In order to induce Lender
to enter into this Third Amendment, SDFC represents and warrants the following:

                     (a) SDFC has the corporate power to execute and deliver
           this Third Amendment and the other Loans Documents executed by it and
           to perform all of its obligations in connection herewith and
           therewith.

                     (b) The execution and delivery by SDFC of this Third
           Amendment and other Loan Documents executed by it and the performance
           of its obligations in connection herewith and therewith: (i) have
           been duly authorized or will be duly ratified and affirmed by all
           requisite corporate action; (ii) will not violate any provision of
           law, any order of any court or agency of government or the Articles
           of Incorporation or Bylaws of such entity; (iii) will not be in
           conflict with, result in a breach of or constitute (alone or with due
           notice or lapse of time or both) a default under any indenture,
           agreement or other instrument; and (iv) will not require any
           registration with, consent or approval of or other action by any
           federal, state, provincial or other governmental authority or
           regulatory body (b) The execution and delivery by SDFC of this

                     (c) There is no action, suit or proceeding at law or in
           equity or by or before any governmental instrumentality or other
           agency or regulatory authority now pending or, to the knowledge of
           SDFC, threatened against or affecting SDFC or any properties or
           rights of SDFC or involving this Third Amendment or the transactions
           contemplated hereby which, if adversely determined, would materially
           impair the right of SDFC, to carry on business substantially as now
           conducted or materially and adversely affect the financial condition
           of SDFC or materially and adversely affect the ability of SDFC to
           consummate the transactions contemplated by this Third Amendment.

                                   ARTICLE IV

                      Ratification of Obligations and Liens

           4.1 Ratification of Obligation. The Borrower and SDFC do each hereby
acknowledge, ratify and confirm their obligations to Lender as evidenced by the
Loan Agreement (as amended by the First Amendment, the Second Amendment and this
Third Amendment) and all other Loan Documents, as modified by the transactions
herein contemplated.

           4.2 Valid Liens. Borrower and SDFC hereby acknowledge and agree that
the liens and security interests of the Loan Documents, as modified by the
transactions herein contemplated, are valid and subsisting liens and security
interests and are superior to all liens and security interests other than those
exceptions approved by Lender in writing. Nothing herein contained shall affect
or impair the validity or priority of the liens and security interests under the
Loan Documents.

           4.3 Ratification of Agreements. The Loan Agreement (as amended by the
First Amendment, Second Amendment and this Third Amendment), and each other Loan
Document, as hereby amended, is acknowledged, ratified and confirmed in all
respects as being valid, existing, and of full force and effect. Any reference
to the Loan Agreement in any Loan Document shall be deemed to be a reference to
the Loan Agreement (as previously amended) as amended by this



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Third Amendment. The execution, delivery and effectiveness of this Third
Amendment shall not, except as expressly provided herein, operate as a waiver of
any right, power or remedy of Lender under the Loan Agreement, not constitute a
waiver of any provision of the Loan Agreement. The Borrower acknowledges,
ratifies and confirms that the collateral securing the Loan secures all of the
indebtedness of the Borrower, including without limitation, the Notes.

                                    ARTICLE V

                                  Miscellaneous

           5.1 Survival of Agreements. All representations, warranties,
covenants and agreements of Borrower, herein or in any other Loan Document shall
survive the execution and delivery of this Third Amendment, and the other Loan
Documents and the performance hereof and thereof, including without limitation
the making or granting of the Loan and the delivery of the Notes and all other
Loan Documents, and shall further survive until all of Borrower's Obligations to
Lender are paid in full. All statements and agreements contained in any
certificate or instrument delivered by Borrower hereunder or under the Loan
Documents to Lender shall be deemed to constitute the respective representations
and warranties by Borrower and/or respective agreements and covenants of
Borrower under this Third Amendment and under the Loan Agreement.

           5.2 Loan Document. This Third Amendment, the Notes, and each other
Loan Documents executed in connection herewith are each a Loan Document and all
provisions in the Loan Agreement, as amended, pertaining to Loan Documents apply
hereto and thereto.

           5.3 Governing Law. This Third Amendment shall be governed by and
construed in all respects in accordance with the laws of the State of Texas and
any applicable laws of the United States of America, including construction,
validity and performance.

           5.4 Counterparts. This Third Amendment may be separately executed in
any number of counterparts and by different parties hereto in separate
counterparts, each of which when so executed shall be deemed to constitute one
and the same Third Amendment.

           5.5 Release of Claims. Borrower by its execution of this Third
Amendment, hereby declares that it has no set-offs, counterclaims, defenses or
other causes of action against Lender arising out of the Loan, the renewal,
modification and extension of the Loan, any documents mentioned herein or
otherwise; and, to the extent any such set-offs, counterclaims, defenses or
other causes of action which may exist, whether known or unknown, such items are
hereby expressly waived and released by Borrower.

           5.6 Attorneys' Fees. Borrower hereby agrees to pay to Lender, upon
demand, the reasonable attorneys' fees and expenses of Lender's counsel, filing
and recording fees and other reasonable expenses incurred by Lender in
connection with this Third Amendment. Borrower also agrees to provide to Lender
such other documents and instruments as Lender may reasonably request in
connection with the renewal, extension and modification of the Loans mentioned
herein.

           5.7 ENTIRE AGREEMENT. THIS THIRD AMENDMENT, TOGETHER WITH ANY LOAN
DOCUMENTS EXECUTED IN CONNECTION HEREWITH, CONTAINS THE ENTIRE AGREEMNT BETWEEN
THE PARTIES HERETO RELATING TO THE SUBJECT MATTER HEREOF AND THEREOF AND ALL
PRIOR AGREEMENTS RELATIVE THERETO WHICH ARE NOT CONTAINED HEREIN AND THEREIN ARE
TERMINATED. THERE ARE NO UNWRITTEN ORAL AGREEMENTS BETWEEN THE PARTIES. THIS
THIRD AMENDMENT, AND THE LOAN DOCUMENTS MAY BE AMENDED, REVISED, WAIVED,
DISCHARGED, RELEASED OR TERMINATED ONLY BY A WRITTEN INSTRUMENT OR INSTRUMENTS,
EXECUTED BY THE PARTY AGAINST WHICH ENFORCEMENT OF THE AMENDMENT, REVISION,
WAIVER, DISCHARGE, RELEASE OR TERMINATION IS ASSERTED. ANY ALLEDGED AMENDMENT
REVISION, WAIVER, DISCHARGE, RELEASE OR TERMINATION WHICH IS NOT SO DOCUMENTED
SHALL NOT BE EFFECTIVE AS TO ANY PARTY.



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           IN WITNESS THEREOF, this Third Amendment is executed effective as of
the date first written above.

BORROWER:                                 SUMMIT BANCSHARES, INC.

                                          By : /s/ Bob G. Scott
                                              ----------------------------------
                                          Its: Executive Vice President
                                              ----------------------------------

LENDER:                                   THE FROST NATIONAL BANK

                                          By : /s/ Jerry L. Crutsinger
                                              ----------------------------------
                                          Its: Senior Vice President
                                              ----------------------------------

GUARANTOR:                                SUMMIT DELAWARE FINANCIAL CORPORATION

                                          By : /s/ Bob G. Scott
                                              ----------------------------------
                                          Its: Executive Vice President
                                              ----------------------------------



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