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                                                                     EXHIBIT 4.6


                               GUARANTEE AGREEMENT

                              THE BANC CORPORATION

                            Dated as of July 16, 2001


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                                TABLE OF CONTENTS

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                                    ARTICLE I
                         DEFINITIONS AND INTERPRETATION

Section 1.1     Definitions and Interpretation ................................1

                                   ARTICLE II
                 POWERS, DUTIES AND RIGHTS OF GUARANTEE TRUSTEE

Section 2.1     Powers and Duties of the Guarantee Trustee ....................4

Section 2.2     Certain Rights of Guarantee Trustee ...........................5

Section 2.3     Not Responsible for Recitals or Issuance of Guarantee .........7

Section 2.4     Events of Default; Waiver .....................................7

Section 2.5     Events of Default; Notice .....................................8

                                   ARTICLE III
                                GUARANTEE TRUSTEE

Section 3.1     Guarantee Trustee; Eligibility ................................8

Section 3.2     Appointment, Removal and Resignation of Guarantee Trustee .....9

                                   ARTICLE IV
                                    GUARANTEE

Section 4.1     Guarantee .....................................................9

Section 4.2     Waiver of Notice and Demand ..................................10

Section 4.3     Obligations Not Affected .....................................10

Section 4.4     Rights of Holders ............................................11

Section 4.5     Guarantee of Payment .........................................11

Section 4.6     Subrogation...................................................11

Section 4.7     Independent Obligations ......................................12

Section 4.8     Enforcement...................................................12

                                    ARTICLE V
                    LIMITATION OF TRANSACTIONS; SUBORDINATION

Section 5.1     Limitation of Transactions ...................................12

Section 5.2     Ranking ......................................................13

                                   ARTICLE VI
                                   TERMINATION

Section 6.1     Termination ..................................................13
</TABLE>


                                      (i)
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<TABLE>
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                                   ARTICLE VII
                                 INDEMNIFICATION

Section 7.1     Exculpation ..................................................13

Section 7.2     Indemnification ..............................................14

Section 7.3     Compensation; Reimbursement of Expenses ......................15

                                  ARTICLE VIII
                                  MISCELLANEOUS


Section 8.1     Successors and Assigns .......................................15

Section 8.2     Amendments ...................................................16

Section 8.3     Notices ......................................................16

Section 8.4     Benefit ......................................................17

Section 8.5     Governing Law ................................................17

Section 8.6     Counterparts .................................................17
</TABLE>


                                      (ii)
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                               GUARANTEE AGREEMENT

                  This GUARANTEE AGREEMENT (the "Guarantee"), dated as of July
16, 2001, is executed and delivered by The Banc Corporation, a financial holding
company incorporated in Delaware (the "Guarantor"), and The Bank of New York, as
trustee (the "Guarantee Trustee"), for the benefit of the Holders (as defined
herein) from time to time of the Capital Securities (as defined herein) of TBC
Capital Statutory Trust III, a Delaware statutory business trust (the "Issuer").

                  WHEREAS, pursuant to an Amended and Restated Declaration of
Trust (the "Declaration"), dated as of July 16, 2001, among the trustees named
therein of the Issuer, The Banc Corporation, as sponsor, and the Holders from
time to time of undivided beneficial interests in the assets of the Issuer, the
Issuer is issuing on the date hereof securities, having an aggregate liquidation
amount of up to $16,000,000, designated the Floating Rate MMCapS(SM) (the
"Capital Securities");

                  WHEREAS, as incentive for the Holders to purchase the Capital
Securities, the Guarantor desires irrevocably and unconditionally to agree, to
the extent set forth in this Guarantee, to pay to the Holders of Capital
Securities the Guarantee Payments (as defined herein) and to make certain other
payments on the terms and conditions set forth herein; and

                  NOW, THEREFORE, in consideration of the purchase by each
Holder of the Capital Securities, which purchase the Guarantor hereby agrees
shall benefit the Guarantor, the Guarantor executes and delivers this Guarantee
for the benefit of the Holders.

                                    ARTICLE I
                         DEFINITIONS AND INTERPRETATION

         Section 1.1  Definitions and Interpretation

                  In this Guarantee, unless the context otherwise requires:

                  (a)      capitalized terms used in this Guarantee but not
         defined in the preamble above have the respective meanings assigned to
         them in this Section 1.1;

                  (b)      a term defined anywhere in this Guarantee has the
         same meaning throughout;

                  (c)      all references to "the Guarantee" or "this Guarantee"
         are to this Guarantee as modified, supplemented or amended from time to
         time;

                  (d)      all references in this Guarantee to Articles and
         Sections are to Articles and Sections of this Guarantee, unless
         otherwise specified;

                  (e)      terms defined in the Declaration as at the date of
         execution of this Guarantee have the same meanings when used in this
         Guarantee, unless otherwise defined in this Guarantee or unless the
         context otherwise requires; and


<PAGE>   5

                  (f)      a reference to the singular includes the plural and
         vice versa.

                  "Beneficiaries" means any Person to whom the Issuer is or
hereafter becomes indebted or liable.

                  "Corporate Trust Office" means the office of the Guarantee
Trustee at which the corporate trust business of the Guarantee Trustee shall, at
any particular time, be principally administered, which office at the date of
execution of this Guarantee Agreement is located at 101 Barclay Street, Floor
21W, New York, NY 10286.

                  "Covered Person" means any Holder of Capital Securities.

                  "Debentures" means the junior subordinated debentures of the
Guarantor, designated the Floating Rate Junior Subordinated Deferrable Interest
Debentures due July 25, 2031, held by the Institutional Trustee (as defined in
the Declaration) of the Issuer.

                  "Event of Default" has the meaning set forth in Section 2.4.

                  "Guarantee Payments" means the following payments or
distributions, without duplication, with respect to the Capital Securities, to
the extent not paid or made by the Issuer: (i) any accrued and unpaid
Distributions (as defined in the Declaration) which are required to be paid on
such Capital Securities to the extent the Issuer shall have funds available in
the Property Account (as defined in the Declaration) therefor at such time, (ii)
the Redemption Price (as defined in the Indenture) to the extent the Issuer has
funds available in the Property Account therefor at such time, with respect to
any Capital Securities called for redemption by the Issuer, (iii) the Special
Redemption Price (as defined in the Indenture) to the extent the Issuer has
funds available in the Property Account therefor at such time, with respect to
Capital Securities called for redemption upon the occurrence of a Special Event
(as defined in the Indenture), and (iv) upon a voluntary or involuntary
liquidation, dissolution, winding-up or termination of the Issuer (other than in
connection with the distribution of Debentures to the Holders of the Capital
Securities in exchange therefor as provided in the Declaration), the lesser of
(a) the aggregate of the liquidation amount and all accrued and unpaid
Distributions on the Capital Securities to the date of payment, to the extent
the Issuer shall have funds available in the Property Account therefor at such
time, and (b) the amount of assets of the Issuer remaining available for
distribution to Holders in liquidation of the Issuer after satisfaction of
liabilities to creditors of the Issuer as required by applicable law (in either
case, the "Liquidation Distribution").

                  "Guarantee Trustee" means The Bank of New York, until a
Successor Guarantee Trustee has been appointed and has accepted such appointment
pursuant to the terms of this Guarantee and thereafter means each such Successor
Guarantee Trustee.

                  "Holder" means any holder, as registered on the books and
records of the Issuer, of any Capital Securities; provided, however, that, in
determining whether the holders of the requisite percentage of Capital
Securities have given any request, notice, consent or waiver hereunder, "Holder"
shall not include the Guarantor or any Affiliate of the Guarantor.


                                       2
<PAGE>   6

                  "Indemnified Person" means the Guarantee Trustee, any
Affiliate of the Guarantee Trustee, or any officers, directors, shareholders,
members, partners, employees, representatives, nominees, custodians or agents of
the Guarantee Trustee.

                  "Indenture" means the Indenture dated as of July 16, 2001,
between the Guarantor and The Bank of New York, not in its individual capacity
but solely as trustee, and any indenture supplemental thereto pursuant to which
the Debentures are to be issued to the Institutional Trustee of the Issuer.

                  "Liquidation Distribution" has the meaning set forth in the
definition of "Guarantee Payments" herein.

                  "Majority in liquidation amount of the Capital Securities"
means Holder(s) of outstanding Capital Securities, voting together as a class,
but separately from the holders of Common Securities, of more than 50% of the
aggregate liquidation amount (including the stated amount that would be paid on
redemption, liquidation or otherwise, plus accrued and unpaid Distributions to,
but excluding, the date upon which the voting percentages are determined) of all
Capital Securities then outstanding.

                  "Obligations" means any costs, expenses or liabilities (but
not including liabilities related to taxes) of the Issuer, other than
obligations of the Issuer to pay to holders of any Trust Securities the amounts
due such holders pursuant to the terms of the Trust Securities.

                  "Officer's Certificate" means, with respect to any Person, a
certificate signed by one Authorized Officer of such Person. Any Officer's
Certificate delivered with respect to compliance with a condition or covenant
provided for in this Guarantee shall include:

                  (a) a statement that each officer signing the Officer's
         Certificate has read the covenant or condition and the definitions
         relating thereto;

                  (b) a brief statement of the nature and scope of the
         examination or investigation undertaken by each officer in rendering
         the Officer's Certificate;

                  (c) a statement that each such officer has made such
         examination or investigation as, in such officer's opinion, is
         necessary to enable such officer to express an informed opinion as to
         whether or not such covenant or condition has been complied with; and

                  (d) a statement as to whether, in the opinion of each such
         officer, such condition or covenant has been complied with.

                  "Person" means a legal person, including any individual,
corporation, estate, partnership, joint venture, association, joint stock
company, limited liability company, trust, unincorporated association, or
government or any agency or political subdivision thereof, or any other entity
of whatever nature.

                  "Responsible Officer" means, with respect to the Guarantee
Trustee, any officer within the Corporate Trust Office of the Guarantee Trustee
including any Vice President, Assistant Vice President, Secretary, Assistant
Secretary or any other officer of the Guarantee


                                       3
<PAGE>   7

Trustee customarily performing functions similar to those performed by any of
the above designated officers and also, with respect to a particular corporate
trust matter, any other officer to whom such matter is referred because of that
officer's knowledge of and familiarity with the particular subject.

                  "Successor Guarantee Trustee" means a successor Guarantee
Trustee possessing the qualifications to act as Guarantee Trustee under Section
3.1.

                  "Trust Securities" means the Common Securities and the Capital
Securities.

                                   ARTICLE II
                 POWERS, DUTIES AND RIGHTS OF GUARANTEE TRUSTEE

         Section 2.1  Powers and Duties of the Guarantee Trustee

                  (a)      This Guarantee shall be held by the Guarantee Trustee
         for the benefit of the Holders of the Capital Securities, and the
         Guarantee Trustee shall not transfer this Guarantee to any Person
         except a Holder of Capital Securities exercising his or her rights
         pursuant to Section 4.4 (b) or to a Successor Guarantee Trustee on
         acceptance by such Successor Guarantee Trustee of its appointment to
         act as Successor Guarantee Trustee. The right, title and interest of
         the Guarantee Trustee shall automatically vest in any Successor
         Guarantee Trustee, and such vesting and cessation of title shall be
         effective whether or not conveyancing documents have been executed and
         delivered pursuant to the appointment of such Successor Guarantee
         Trustee.

                  (b)      If an Event of Default actually known to a
         Responsible Officer of the Guarantee Trustee has occurred and is
         continuing, the Guarantee Trustee shall enforce this Guarantee for the
         benefit of the Holders of the Capital Securities.

                  (c)      The Guarantee Trustee, before the occurrence of any
         Event of Default and after curing all Events of Default that may have
         occurred, shall undertake to perform only such duties as are
         specifically set forth in this Guarantee, and no implied covenants
         shall be read into this Guarantee against the Guarantee Trustee. In
         case an Event of Default has occurred (that has not been cured or
         waived pursuant to Section 2.4) and is actually known to a Responsible
         Officer of the Guarantee Trustee, the Guarantee Trustee shall exercise
         such of the rights and powers vested in it by this Guarantee, and use
         the same degree of care and skill in its exercise thereof, as a prudent
         person would exercise or use under the circumstances in the conduct of
         his or her own affairs.

                  (d)      No provision of this Guarantee shall be construed to
         relieve the Guarantee Trustee from liability for its own negligent
         action, its own negligent failure to act, or its own willful
         misconduct, except that:

                           (i) prior to the occurrence of any Event of Default
         and after the curing or waiving of all such Events of Default that may
         have occurred:

                                    (A) the duties and obligations of the
                           Guarantee Trustee shall be determined solely by the
                           express provisions of this Guarantee, and the


                                       4
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                           Guarantee Trustee shall not be liable except for the
                           performance of such duties and obligations as are
                           specifically set forth in this Guarantee, and no
                           implied covenants or obligations shall be read into
                           this Guarantee against the Guarantee Trustee; and

                                    (B) in the absence of bad faith on the part
                           of the Guarantee Trustee, the Guarantee Trustee may
                           conclusively rely, as to the truth of the statements
                           and the correctness of the opinions expressed
                           therein, upon any certificates or opinions furnished
                           to the Guarantee Trustee and conforming to the
                           requirements of this Guarantee; but in the case of
                           any such certificates or opinions furnished to the
                           Guarantee Trustee, the Guarantee Trustee shall be
                           under a duty to examine the same to determine whether
                           or not they conform to the requirements of this
                           Guarantee;

                           (ii) the Guarantee Trustee shall not be liable for
         any error of judgment made in good faith by a Responsible Officer of
         the Guarantee Trustee, unless it shall be proved that such Responsible
         Officer of the Guarantee Trustee or the Guarantee Trustee was negligent
         in ascertaining the pertinent facts upon which such judgment was made;

                           (iii) the Guarantee Trustee shall not be liable with
         respect to any action taken or omitted to be taken by it in good faith
         in accordance with the written direction of the Holders of not less
         than a Majority in liquidation amount of the Capital Securities
         relating to the time, method and place of conducting any proceeding for
         any remedy available to the Guarantee Trustee, or exercising any trust
         or power conferred upon the Guarantee Trustee under this Guarantee; and

                           (iv) no provision of this Guarantee shall require the
         Guarantee Trustee to expend or risk its own funds or otherwise incur
         personal financial liability in the performance of any of its duties or
         in the exercise of any of its rights or powers, if the Guarantee
         Trustee shall have reasonable grounds for believing that the repayment
         of such funds is not reasonably assured to it under the terms of this
         Guarantee, or security and indemnity, reasonably satisfactory to the
         Guarantee Trustee, against such risk or liability is not reasonably
         assured to it.

          Section 2.2  Certain Rights of Guarantee Trustee

                  (a)      Subject to the provisions of Section 2.1:

                           (i) The Guarantee Trustee may conclusively rely, and
         shall be fully protected in acting or refraining from acting upon, any
         resolution, certificate, statement, instrument, opinion, report,
         notice, request, direction, consent, order, bond, debenture, note,
         other evidence of indebtedness or other paper or document believed by
         it to be genuine and to have been signed, sent or presented by the
         proper party or parties.

                           (ii) Any direction or act of the Guarantor
         contemplated by this Guarantee shall be sufficiently evidenced by an
         Officer's Certificate.


                                       5
<PAGE>   9

                           (iii) Whenever, in the administration of this
         Guarantee, the Guarantee Trustee shall deem it desirable that a matter
         be proved or established before taking, suffering or omitting any
         action hereunder, the Guarantee Trustee (unless other evidence is
         herein specifically prescribed) may, in the absence of bad faith on its
         part, request and conclusively rely upon an Officer's Certificate of
         the Guarantor which, upon receipt of such request, shall be promptly
         delivered by the Guarantor.

                           (iv) The Guarantee Trustee shall have no duty to see
         to any recording, filing or registration of any instrument (or any
         rerecording, refiling or registration thereof).

                           (v) The Guarantee Trustee may consult with counsel of
         its selection, and the advice or opinion of such counsel with respect
         to legal matters shall be full and complete authorization and
         protection in respect of any action taken, suffered or omitted by it
         hereunder in good faith and in accordance with such advice or opinion.
         Such counsel may be counsel to the Guarantor or any of its Affiliates
         and may include any of its employees. The Guarantee Trustee shall have
         the right at any time to seek instructions concerning the
         administration of this Guarantee from any court of competent
         jurisdiction.

                           (vi) The Guarantee Trustee shall be under no
         obligation to exercise any of the rights or powers vested in it by this
         Guarantee at the request or direction of any Holder, unless such Holder
         shall have provided to the Guarantee Trustee such security and
         indemnity, reasonably satisfactory to the Guarantee Trustee, against
         the costs, expenses (including attorneys' fees and expenses and the
         expenses of the Guarantee Trustee's agents, nominees or custodians) and
         liabilities that might be incurred by it in complying with such request
         or direction, including such reasonable advances as may be requested by
         the Guarantee Trustee; provided, however that nothing contained in this
         Section 2.2(a)(vi) shall be taken to relieve the Guarantee Trustee,
         upon the occurrence of an Event of Default, of its obligation to
         exercise the rights and powers vested in it by this Guarantee.

                           (vii) The Guarantee Trustee shall not be bound to
         make any investigation into the facts or matters stated in any
         resolution, certificate, statement, instrument, opinion, report,
         notice, request, direction, consent, order, bond, debenture, note,
         other evidence of indebtedness or other paper or document, but the
         Guarantee Trustee, in its discretion, may make such further inquiry or
         investigation into such facts or matters as it may see fit.

                           (viii) The Guarantee Trustee may execute any of the
         trusts or powers hereunder or perform any duties hereunder either
         directly or by or through agents, nominees, custodians or attorneys,
         and the Guarantee Trustee shall not be responsible for any misconduct
         or negligence on the part of any agent or attorney appointed with due
         care by it hereunder.

                           (ix) Any action taken by the Guarantee Trustee or its
         agents hereunder shall bind the Holders of the Capital Securities, and
         the signature of the Guarantee Trustee or its agents alone shall be
         sufficient and effective to perform any such action.


                                       6
<PAGE>   10

         No third party shall be required to inquire as to the authority of the
         Guarantee Trustee to so act or as to its compliance with any of the
         terms and provisions of this Guarantee, both of which shall be
         conclusively evidenced by the Guarantee Trustee's or its agent's taking
         such action.

                           (x) Whenever in the administration of this Guarantee
         the Guarantee Trustee shall deem it desirable to receive instructions
         with respect to enforcing any remedy or right or taking any other
         action hereunder, the Guarantee Trustee (A) may request instructions
         from the Holders of a Majority in liquidation amount of the Capital
         Securities, (B) may refrain from enforcing such remedy or right or
         taking such other action until such instructions are received and (C)
         shall be protected in conclusively relying on or acting in accordance
         with such instructions.

                           (xi) The Guarantee Trustee shall not be liable for
         any action taken, suffered, or omitted to be taken by it in good faith
         and reasonably believed by it to be authorized or within the discretion
         or rights or powers conferred upon it by this Guarantee.

                  (b)      No provision of this Guarantee shall be deemed to
         impose any duty or obligation on the Guarantee Trustee to perform any
         act or acts or exercise any right, power, duty or obligation conferred
         or imposed on it, in any jurisdiction in which it shall be illegal or
         in which the Guarantee Trustee shall be unqualified or incompetent in
         accordance with applicable law to perform any such act or acts or to
         exercise any such right, power, duty or obligation. No permissive power
         or authority available to the Guarantee Trustee shall be construed to
         be a duty.

         Section 2.3  Not Responsible for Recitals or Issuance of Guarantee

                  The recitals contained in this Guarantee shall be taken as the
statements of the Guarantor, and the Guarantee Trustee does not assume any
responsibility for their correctness. The Guarantee Trustee makes no
representation as to the validity or sufficiency of this Guarantee.

         Section 2.4  Events of Default; Waiver

                  (a)      An Event of Default under this Guarantee will occur
         upon the failure of the Guarantor to perform any of its payment or
         other obligations hereunder.

                  (b)      The Holders of a Majority in liquidation amount of
         Capital Securities may, voting or consenting as a class, on behalf of
         the Holders of all of the Capital Securities, waive any past Event of
         Default and its consequences. Upon such waiver, any such Event of
         Default shall cease to exist, and shall be deemed to have been cured,
         for every purpose of this Guarantee, but no such waiver shall extend to
         any subsequent or other default or Event of Default or impair any right
         consequent thereon.


                                       7
<PAGE>   11

         Section 2.5  Events of Default; Notice

                  (a)      The Guarantee Trustee shall, within 90 days after
         the occurrence of an Event of Default, transmit by mail, first class
         postage prepaid, to the Holders of the Capital Securities, notices of
         all Events of Default actually known to a Responsible Officer of the
         Guarantee Trustee, unless such defaults have been cured before the
         giving of such notice, provided, however, that the Guarantee Trustee
         shall be protected in withholding such notice if and so long as a
         Responsible Officer of the Guarantee Trustee in good faith determines
         that the withholding of such notice is in the interests of the Holders
         of the Capital Securities.

                  (b)      The Guarantee Trustee shall not be deemed to have
         knowledge of any Event of Default unless the Guarantee Trustee shall
         have received written notice from the Guarantor or a Holder of the
         Capital Securities (except in the case of a payment default), or a
         Responsible Officer of the Guarantee Trustee charged with the
         administration of this Guarantee shall have obtained actual knowledge,
         thereof.

                                   ARTICLE III
                                GUARANTEE TRUSTEE

         Section 3.1  Guarantee Trustee; Eligibility

                  (a)      There shall at all times be a Guarantee Trustee which
         shall:

                           (i) not be an Affiliate of the Guarantor; and

                           (ii) be a corporation organized and doing business
         under the laws of the United States of America or any State or
         Territory thereof or of the District of Columbia, or Person authorized
         under such laws to exercise corporate trust powers, having a combined
         capital and surplus of at least 50 million U.S. dollars ($50,000,000),
         and subject to supervision or examination by Federal, State,
         Territorial or District of Columbia authority. If such corporation
         publishes reports of condition at least annually, pursuant to law or to
         the requirements of the supervising or examining authority referred to
         above, then, for the purposes of this Section 3.1(a) (ii), the combined
         capital and surplus of such corporation shall be deemed to be its
         combined capital and surplus as set forth in its most recent report of
         condition so published.

                  (b)      If at any time the Guarantee Trustee shall cease to
         be eligible to so act under Section 3.1(a), the Guarantee Trustee
         shall immediately resign in the manner and with the effect set out in
         Section 3.2(c).

                  (c)      If the Guarantee Trustee has or shall acquire any
         "conflicting interest" within the meaning of Section 310(b) of the
         Trust Indenture Act, the Guarantee Trustee shall either eliminate such
         interest or resign to the extent and in the manner provided by, and
         subject to this Guarantee.


                                       8
<PAGE>   12
         Section 3.2       Appointment, Removal and Resignation of Guarantee
                           Trustee

                  (a)      Subject to Section 3.2(b), the Guarantee Trustee may
         be appointed or removed without cause at any time by the Guarantor
         except during an Event of Default.

                  (b)      The Guarantee Trustee shall not be removed in
         accordance with Section 3.2(a) until a Successor Guarantee Trustee has
         been appointed and has accepted such appointment by written instrument
         executed by such Successor Guarantee Trustee and delivered to the
         Guarantor.

                  (c)      The Guarantee Trustee appointed to office shall hold
         office until a Successor Guarantee Trustee shall have been appointed or
         until its removal or resignation. The Guarantee Trustee may resign from
         office (without need for prior or subsequent accounting) by an
         instrument in writing executed by the Guarantee Trustee and delivered
         to the Guarantor, which resignation shall not take effect until a
         Successor Guarantee Trustee has been appointed and has accepted such
         appointment by an instrument in writing executed by such Successor
         Guarantee Trustee and delivered to the Guarantor and the resigning
         Guarantee Trustee.

                  (d)      If no Successor Guarantee Trustee shall have been
         appointed and accepted appointment as provided in this Section 3.2
         within 60 days after delivery of an instrument of removal or
         resignation, the Guarantee Trustee resigning or being removed may
         petition any court of competent jurisdiction for appointment of a
         Successor Guarantee Trustee. Such court may thereupon, after
         prescribing such notice, if any, as it may deem proper, appoint a
         Successor Guarantee Trustee.

                  (e)      No Guarantee Trustee shall be liable for the acts or
         omissions to act of any Successor Guarantee Trustee.

                  (f)      Upon termination of this Guarantee or removal or
         resignation of the Guarantee Trustee pursuant to this Section 3.2,
         the Guarantor shall pay to the Guarantee Trustee all amounts owing to
         the Guarantee Trustee under Sections 7.2 and 7.3 accrued to the date of
         such termination, removal or resignation.

                                   ARTICLE IV
                                   GUARANTEE

         Section 4.1       Guarantee

                  (a)      The Guarantor irrevocably and unconditionally agrees
         to pay in full to the Holders the Guarantee Payments (without
         duplication of amounts theretofore paid by the Issuer), as and when
         due, regardless of any defense (except as defense of payment by the
         Issuer), right of set-off or counterclaim that the Issuer may have or
         assert. The Guarantor's obligation to make a Guarantee Payment may be
         satisfied by direct payment of the required amounts by the Guarantor to
         the Holders or by causing the Issuer to pay such amounts to the
         Holders.


                                        9

<PAGE>   13

                  (b)      The Guarantor hereby also agrees to assume any and
         all Obligations of the Issuer and in the event any such Obligation is
         not so assumed, subject to the terms and conditions hereof, the
         Guarantor hereby irrevocably and unconditionally guarantees to each
         Beneficiary the full payment, when and as due, of any and all
         obligations to such Beneficiaries. This Agreement is intended to be for
         the Beneficiaries who have received notice hereof.

         Section 4.2       Waiver of Notice and Demand

         The Guarantor hereby waives notice of acceptance of this Guarantee and
of any liability to which it applies or may apply, presentment, demand for
payment, any right to require a proceeding first against the Issuer or any other
Person before proceeding against the Guarantor, protest, notice of nonpayment,
notice of dishonor, notice of redemption and all other notices and demands.

         Section 4.3       Obligations Not Affected

         The obligations, covenants, agreements and duties of the Guarantor
under this Guarantee shall in no way be affected or impaired by reason of the
happening from time to time of any of the following:

                  (a)      the release or waiver, by operation of law or
         otherwise, of the performance or observance by the Issuer of any
         express or implied agreement, covenant, term or condition relating to
         the Capital Securities to be performed or observed by the Issuer;

                  (b)      the extension of time for the payment by the Issuer
         of all or any portion of the Distributions, Redemption Price, Special
         Redemption Price, Liquidation Distribution or any other sums payable
         under the terms of the Capital Securities or the extension of time for
         the performance of any other obligation under, arising out of, or in
         connection with, the Capital Securities (other than an extension of
         time for payment of Distributions, Redemption Price, Special Redemption
         Price, Liquidation Distribution or other sum payable that results from
         the extension of any interest payment period on the Debentures or any
         extension of the maturity date of the Debentures permitted by the
         Indenture);

                  (c)      any failure, omission, delay or lack of diligence on
         the part of the Holders to enforce, assert or exercise any right,
         privilege, power or remedy conferred on the Holders pursuant to the
         terms of the Capital Securities, or any action on the part of the
         Issuer granting indulgence or extension of any kind;

                  (d)      the voluntary or involuntary liquidation,
         dissolution, sale of any collateral, receivership, insolvency,
         bankruptcy, assignment for the benefit of creditors, reorganization,
         arrangement, composition or readjustment of debt of, or other similar
         proceedings affecting, the Issuer or any of the assets of the Issuer;

                  (e)      any invalidity of, or defect or deficiency in, the
         Capital Securities;

                  (f)      the settlement or compromise of any obligation
         guaranteed hereby or hereby incurred; or


                                       10

<PAGE>   14

                  (g)      any other circumstance whatsoever that might
         otherwise constitute a legal or equitable discharge or defense of a
         guarantor, it being the intent of this Section 4.3 that the obligations
         of the Guarantor hereunder shall be absolute and unconditional under
         any and all circumstances.

         There shall be no obligation of the Holders to give notice to, or
obtain consent of, the Guarantor with respect to the happening of any of the
foregoing.

         Section 4.4       Rights of Holders

                  (a)      The Holders of a Majority in liquidation amount of
         the Capital Securities have the right to direct the time, method and
         place of conducting any proceeding for any remedy available to the
         Guarantee Trustee in respect of this Guarantee or to direct the
         exercise of any trust or power conferred upon the Guarantee Trustee
         under this Guarantee; provided, however, that (subject to Sections 2.1
         and 2.2) the Guarantee Trustee shall have the right to decline to
         follow any such direction if the Guarantee Trustee shall determine that
         the actions so directed would be unjustly prejudicial to the Holders
         not taking part in such direction or if the Guarantee Trustee being
         advised by counsel determines that the action or proceeding so directed
         may not lawfully be taken or if the Guarantor Trustee in good faith by
         its board of directors or trustees, executive committees or a trust
         committee of directors or trustees and/or Responsible Officers shall
         determine that the action or proceedings so directed would involve the
         Guarantee Trustee in personal liability.

                  (b)      Any Holder of Capital Securities may institute a
         legal proceeding directly against the Guarantor to enforce the
         Guarantee Trustee's rights under this Guarantee, without first
         instituting a legal proceeding against the Issuer, the Guarantee
         Trustee or any other Person. The Guarantor waives any right or remedy
         to require that any such action be brought first against the Issuer,
         the Guarantee Trustee or any other Person before so proceeding directly
         against the Guarantor.

         Section 4.5       Guarantee of Payment

         This Guarantee creates a guarantee of payment and not of collection.

         Section 4.6       Subrogation

         The Guarantor shall be subrogated to all (if any) rights of the Holders
of Capital Securities against the Issuer in respect of any amounts paid to such
Holders by the Guarantor under this Guarantee; provided however, that the
Guarantor shall not (except to the extent required by applicable provisions of
law) be entitled to enforce or exercise any right that it may acquire by way of
subrogation or any indemnity, reimbursement or other agreement, in all cases as
a result of payment under this Guarantee, if, after giving effect to any such
payment, any amounts are due and unpaid under this Guarantee. If any amount
shall be paid to the Guarantor in violation of the preceding sentence, the
Guarantor agrees to hold such amount in trust for the Holders and to pay over
such amount to the Holders.


                                       11

<PAGE>   15

         Section 4.7       Independent Obligations

         The Guarantor acknowledges that its obligations hereunder are
independent of the obligations of the Issuer with respect to the Capital
Securities and that the Guarantor shall be liable as principal and as debtor
hereunder to make Guarantee Payments pursuant to the terms of this Guarantee
notwithstanding the occurrence of any event referred to in subsections (a)
through (g), inclusive, of Section 4.3 hereof.

         Section 4.8       Enforcement

         A Beneficiary may enforce the obligations of the Guarantor contained in
Section 4.1 (b) directly against the Guarantor, and the Guarantor waives any
right or remedy to require that any action be brought against the Issuer or any
other person or entity before proceeding against the Guarantor.

         The Guarantor shall be subrogated to all rights (if any) of any
Beneficiary against the Issuer in respect of any amounts paid to the
Beneficiaries by the Guarantor under this Guarantee; provided, however, that
the Guarantor shall not (except to the extent required by applicable provisions
of law) be entitled to enforce or exercise any rights that it may acquire by way
of subrogation or any indemnity, reimbursement or other agreement, in all cases
as a result of payment under this Guarantee, if, after giving effect to such
payment, any amounts are due and unpaid under this Guarantee.

                                    ARTICLE V
                    LIMITATION OF TRANSACTIONS; SUBORDINATION

         Section 5.1       Limitation of Transactions

         So long as any Capital Securities remain outstanding, if (a) there
shall have occurred and be continuing an Event of Default or (b) the Guarantor
shall have selected an Extension Period as provided in the Declaration and such
period, or any extension thereof, shall have commenced and be continuing, then
the Guarantor may not (x) declare or pay any dividends or distributions on, or
redeem, purchase, acquire, or make a liquidation payment with respect to, any of
the Guarantor's capital stock or (y) make any payment of principal of or
interest or premium, if any, on or repay, repurchase or redeem any debt
securities of the Guarantor that rank pari passu in all respects with or junior
in interest to the Debentures (other than (i) payments under this Guarantee,
(ii) repurchases, redemptions or other acquisitions of shares of capital stock
of the Guarantor in connection with any employment contract, benefit plan or
other similar arrangement with or for the benefit of one or more employees,
officers, directors, or consultants, in connection with a dividend reinvestment
or stockholder stock purchase plan or in connection with the issuance of capital
stock of the Guarantor (or securities convertible into or exercisable for such
capital stock) as consideration in an acquisition transaction entered into prior
to occurrence of the Event of Default or the applicable Extension Period, (iii)
as a result of any exchange of conversion of any class or series of the
Guarantor's capital stock (or any capital stock of a subsidiary of the
Guarantor) for any class or series of the Guarantor's capital stock or of any
class or series of the Guarantor's indebtedness for any class or series of the
Guarantor's capital stock, (iv) the purchase of fractional interests in shares
of the


                                       12

<PAGE>   16

Guarantor's capital stock pursuant to the conversion or exchange provisions of
such capital stock or the security being converted or exchanged, (v) any
declaration of a dividend in connection with any stockholder's rights plan, or
the issuance of rights, stock or other property under any stockholder's rights
plan, or the redemption or repurchase of rights pursuant thereto, or (vi) any
dividend in the form of stock, warrants, options or other rights where the
dividend stock or the stock issuable upon exercise of such warrants, options or
other rights is the same stock as that on which the dividend is being paid or
ranks pari passu with or junior to such stock).

         Section 5.2       Ranking

         This Guarantee will constitute an unsecured obligation of the Guarantor
and will rank subordinate and junior in right of payment to all present and
future Senior Indebtedness (as defined in the Indenture) of the Guarantor. By
their acceptance thereof, each Holder of Capital Securities agrees to the
foregoing provisions of this Guarantee and the other terms set forth herein.

         The right of the Guarantor to participate in any distribution of assets
of any of its subsidiaries upon any such subsidiary's liquidation or
reorganization or otherwise is subject to the prior claims of creditors of that
subsidiary, except to the extent the Guarantor may itself be recognized as a
creditor of that subsidiary. Accordingly, the Guarantor's obligations under this
Guarantee will be effectively subordinated to all existing and future
liabilities of the Guarantor's subsidiaries, and claimants should look only to
the assets of the Guarantor for payments thereunder. This Guarantee does not
limit the incurrence or issuance of other secured or unsecured debt of the
Guarantor, including Senior Indebtedness of the Guarantor, under any indenture
or agreement that the Guarantor may enter into in the future or otherwise.

                                   ARTICLE VI
                                   TERMINATION

         Section 6.1       Termination

         This Guarantee shall terminate as to the Capital Securities (i) upon
full payment of the Redemption Price or the Special Redemption Price, as the
case may be, of all Capital Securities then outstanding, (ii) upon the
distribution of all of the Debentures to the Holders of all of the Capital
Securities or (iii) upon full payment of the amounts payable in accordance with
the Declaration upon dissolution of the Issuer. This Guarantee will continue to
be effective or will be reinstated, as the case may be, if at any time any
Holder of Capital Securities must restore payment of any sums paid under the
Capital Securities or under this Guarantee.

                                   ARTICLE VII
                                 INDEMNIFICATION

         Section 7.1       Exculpation

                  (a)      No Indemnified Person shall be liable, responsible or
         accountable in damages or otherwise to the Guarantor or any Covered
         Person for any loss, damage or claim incurred by reason of any act or
         omission performed or omitted by such Indemnified Person in good faith
         in accordance with this Guarantee and in a manner that


                                       13

<PAGE>   17

         such Indemnified Person reasonably believed to be within the scope of
         the authority conferred on such Indemnified Person by this Guarantee or
         by law, except that an Indemnified Person shall be liable for any such
         loss, damage or claim incurred by reason of such Indemnified Person's
         negligence or willful misconduct with respect to such acts or
         omissions.

                  (b)      An Indemnified Person shall be fully protected in
         relying in good faith upon the records of the Issuer or the Guarantor
         and upon such information, opinions, reports or statements presented to
         the Issuer or the Guarantor by any Person as to matters the Indemnified
         Person reasonably believes are within such other Person's professional
         or expert competence and who, if selected by such Indemnified Person,
         has been selected with reasonable care by such Indemnified Person,
         including information, opinions, reports or statements as to the value
         and amount of the assets, liabilities, profits, losses, or any other
         facts pertinent to the existence and amount of assets from which
         Distributions to Holders of Capital Securities might properly be paid.

         Section 7.2       Indemnification

                  (a)      The Guarantor agrees to indemnify each Indemnified
         Person for, and to hold each Indemnified Person harmless against, any
         and all loss, liability, damage, claim or expense incurred without
         negligence or willful misconduct on the part of the Indemnified Person,
         arising out of or in connection with the acceptance or administration
         of the trust or trusts hereunder, including but not limited to the
         costs and expenses (including reasonable legal fees and expenses) of
         the Indemnified Person defending itself against, or investigating, any
         claim or liability in connection with the exercise or performance of
         any of the Indemnified Person's powers or duties hereunder. The
         obligation to indemnify as set forth in this Section 7.2 shall survive
         the resignation or removal of the Guarantee Trustee and the termination
         of this Guarantee.

                  (b)      Promptly after receipt by an Indemnified Person under
         this Section 7.2 of notice of the commencement of any action, such
         Indemnified Person will, if a claim in respect thereof is to be made
         against the Guarantor under this Section 7.2, notify the Guarantor in
         writing of the commencement thereof; but the failure so to notify the
         Guarantor (i) will not relieve the Guarantor from liability under
         paragraph (a) above unless and to the extent that the Guarantor did not
         otherwise learn of such action and such failure results in the
         forfeiture by the Guarantor of substantial rights and defenses and (ii)
         will not, in any event, relieve the Guarantor from any obligations to
         any Indemnified Person other than the indemnification obligation
         provided in paragraph (a) above. The Guarantor shall be entitled to
         appoint counsel of the Guarantor's choice at the Guarantor's expense to
         represent the Indemnified Person in any action for which
         indemnification is sought (in which case the Guarantor shall not
         thereafter be responsible for the fees and expenses of any separate
         counsel retained by the Indemnified Person or Persons except as set
         forth below); provided, however, that such counsel shall be
         satisfactory to the Indemnified Person. Notwithstanding the Guarantor's
         election to appoint counsel to represent the Guarantor in an action,
         the Indemnified Person shall have the right to employ separate counsel
         (including local counsel), and the Guarantor shall bear the reasonable
         fees, costs and expenses of such separate counsel if (1) the use of


                                       14

<PAGE>   18

         counsel chosen by the Guarantor to represent the Indemnified Person
         would present such counsel with a conflict of interest, (ii) the actual
         or potential defendants in, or targets of, any such action include both
         the Indemnified Person and the Guarantor and the Indemnified Person
         shall have reasonably concluded that there may be legal defenses
         available to it and/or other Indemnified Person which are different
         from or additional to those available to the Guarantor, (iii) the
         Guarantor shall not have employed counsel satisfactory to the
         Indemnified Person to represent the Indemnified Person within a
         reasonable time after notice of the institution of such action or (iv)
         the Guarantor shall authorize the Indemnified Person to employ separate
         counsel at the expense of the Guarantor. The Guarantor will not,
         without the prior written consent of the Indemnified Persons, settle or
         compromise or consent to the entry of any judgment with respect to any
         pending or threatened claim, action, suit or proceeding in respect of
         which indemnification or contribution may be sought hereunder (whether
         or not the Indemnified Persons are actual or potential parties to such
         claim or action) unless such settlement, compromise or consent includes
         an unconditional release of each Indemnified Person from all liability
         arising out of such claim, action, suit or proceeding.

         Section 7.3       Compensation. Reimbursement of Expenses

         The Guarantor agrees:

                  (a)      to pay to the Guarantee Trustee from time to time
         such compensation for all services rendered by it hereunder as the
         parties shall agree to from time to time (which compensation shall not
         be limited by any provision of law in regard to the compensation of a
         trustee of an express trust); and

                  (b)      except as otherwise expressly provided herein, to
         reimburse the Guarantee Trustee upon request for all reasonable
         expenses, disbursements and advances incurred or made by it in
         accordance with any provision of this Guarantee (including the
         reasonable compensation and the expenses and disbursements of its
         agents and counsel), except any such expense, disbursement or advance
         as may be attributable to its negligence or willful misconduct.

         The provisions of this Section 7.3 shall survive the resignation or
removal of the Guarantee Trustee and the termination of this Guarantee.

                                  ARTICLE VIII
                                  MISCELLANEOUS

         Section 8.1       Successors and Assigns

         All guarantees and agreements contained in this Guarantee shall bind
the successors, assigns, receivers, trustees and representatives of the
Guarantor and shall inure to the benefit of the Holders of the Capital
Securities then outstanding. Except in connection with any merger or
consolidation of the Guarantor with or into another entity or any sale, transfer
or lease of the Guarantor's assets to another entity, in each case, to the
extent permitted under the Indenture, the Guarantor may not assign its rights or
delegate its obligations under this Guarantee


                                       15

<PAGE>   19

without the prior approval of the Holders of at least a Majority in liquidation
amount of the Capital Securities.

         Section 8.2       Amendments

         Except with respect to any changes that do not adversely affect the
rights of Holders of the Capital Securities in any material respect (in which
case no consent of Holders will be required), this Guarantee may be amended only
with the prior approval of the Holders of not less than a Majority in
liquidation amount of the Capital Securities. The provisions of the Declaration
with respect to amendments thereof shall apply equally with respect to
amendments of the Guarantee.

         Section 8.3       Notices

         All notices provided for in this Guarantee shall be in writing, duly
signed by the party giving such notice, and shall be delivered, telecopied or
mailed by first class mail, as follows:

                  (a)      If given to the Guarantee Trustee, at the Guarantee
         Trustee's mailing address set forth below (or such other address as the
         Guarantee Trustee may give notice of to the Holders of the Capital
         Securities):

                           The Bank of New York
                           101 Barclay Street, Floor 21W
                           New York, NY 10286
                           Attention: Corporate Trust Administration
                           Telecopy: 212-815-5915

                  (b)      If given to the Guarantor, at the Guarantor's mailing
         address set forth below (or such other address as the Guarantor may
         give notice of to the Holders of the Capital Securities and to the
         Guarantee Trustee):

                           The Banc Corporation
                           17 North 20th Street
                           Birmingham, Alabama 35203
                           Attention: James A. Taylor, Jr.
                           Telecopy: 205-327-3479

                           With a copy to:
                           The Banc Corporation
                           17 North 20th Street
                           Birmingham, Alabama 35203
                           Attention: F. Hampton McFadden, Jr.
                           Telecopy: 205-327-3479

                  (c)      If given to any Holder of the Capital Securities, at
         the address set forth on the books and records of the Issuer.


                                       16

<PAGE>   20

         All such notices shall be deemed to have been given when received in
person, telecopied with receipt confirmed, or mailed by first class mail,
postage prepaid except that if a notice or other document is refused delivery or
cannot be delivered because of a changed address of which no notice was given,
such notice or other document shall be deemed to have been delivered on the date
of such refusal or inability to deliver.

         Section 8.4       Benefit

         This Guarantee is solely for the benefit of the Holders of the Capital
Securities and, subject to Section 2. 1(a), is not separately transferable from
the Capital Securities.

         Section 8.5       Governing Law

         THIS GUARANTEE SHALL BE GOVERNED BY, AND CONSTRUED IN ACCORDANCE WITH,
THE LAW OF THE STATE OF NEW YORK, WITHOUT REGARD TO CONFLICT OF LAWS PRINCIPLES
THEREOF.

         Section 8.6       Counterparts

         This Guarantee may contain more than one counterpart of the signature
page and this Guarantee may be executed by the affixing of the signature of the
Guarantor and the Guarantee Trustee to any of such counterpart signature pages.
All of such counterpart signature pages shall be read as though one, and they
shall have the same force and effect as though all of the signers had signed a
single signature page.


                                       17

<PAGE>   21

         THIS GUARANTEE is executed as of the day and year first above written.



                                       THE BANC CORPORATION,
                                       as Guarantor



                                       By: /s/ David R. Carter
                                          --------------------------------------
                                          David R. Carter
                                          Executive Vice President and
                                          Chief Financial Officer



                                       THE BANK OF NEW YORK,
                                       as Guarantee Trustee



                                       By: /s/ Mary LaGumina
                                          --------------------------------------
                                           Name: MARY LaGUMINA
                                           Title: Vice President