<PAGE>

                                   EXHIBIT 4.7

                    PREFERRED SECURITIES GUARANTEE AGREEMENT

                          SPECTRUM BANCORPORATION, INC.

                                       AND

                            WILMINGTON TRUST COMPANY

                         DATED: _________________, 2001

<PAGE>


                                TABLE OF CONTENTS

<TABLE>
<CAPTION>

                                                                            PAGE
                                                                            ----
<S>                                                                         <C>
ARTICLE I      DEFINITIONS AND INTERPRETATION                                1

SECTION 1.1    Definitions and Interpretation                                1

ARTICLE II     TRUST INDENTURE ACT                                           5

SECTION 2.1    Trust Indenture Act; Application                              5

SECTION 2.2    Lists of Holders of Securities                                5

SECTION 2.3    Reports by the Preferred Guarantee Trustee                    6

SECTION 2.4    Periodic Reports to Preferred Guarantee Trustee               6

SECTION 2.5    Evidence of Compliance with Conditions Precedent              6

SECTION 2.6    Events of Default; Waiver                                     6

SECTION 2.7    Event of Default; Notice                                      6

SECTION 2.8    Conflicting Interests                                         7

ARTICLE III    POWER, DUTIES AND RIGHTS OF
               PREFERRED GUARANTEE TRUSTEE                                   7

SECTION 3.1    Powers and Duties of the Preferred
               Guarantee Trustee                                             7

SECTION 3.2    Certain Rights of Preferred Guarantee
               Trustee                                                       9

SECTION 3.3    Not Responsible for Recitals or Issuance
               of Guarantee                                                  11

ARTICLE IV     PREFERRED GUARANTEE TRUSTEE                                   11

SECTION 4.1    Preferred Guarantee Trustee; Eligibility                      11
</TABLE>


                                       i

<PAGE>

<TABLE>

<S>                                                                         <C>
SECTION 4.2    Appointment, Removal and Resignation
               of Preferred Guarantee Trustees                               12

ARTICLE V      GUARANTEE                                                     13

SECTION 5.1    Guarantee                                                     13

SECTION 5.2    Waiver of Notice and Demand                                   13

SECTION 5.3    Obligations Not Affected                                      13

SECTION 5.4    Rights of Holders                                             14

SECTION 5.5    Guarantee of Payment                                          14

SECTION 5.6    Subrogation                                                   14

SECTION 5.7    Independent Obligations                                       14

ARTICLE VI     LIMITATION OF TRANSACTIONS;
               SUBORDINATION                                                 15

SECTION 6.1    Limitation of Transactions                                    15

SECTION 6.2    Ranking                                                       15

ARTICLE VII    TERMINATION                                                   15

SECTION 7.1    Termination                                                   15

ARTICLE VIII   INDEMNIFICATION                                               16

Section 8.1    Exculpation                                                   16

Section 8.2    Indemnification                                               16

ARTICLE IX     MISCELLANEOUS                                                 16

Section 9.1    Successors and Assigns                                        16

Section 9.2    Amendments                                                    16

Section 9.3    Notices                                                       17

Section 9.4    Benefit                                                       17

Section 9.5    Governing Law                                                 17
</TABLE>


                                       ii

<PAGE>


                              CROSS REFERENCE TABLE

<TABLE>
<CAPTION>

Section of Trust                                 Section of
Indenture Act of                                 Guarantee
1939, as Amended                                 Agreement
                                                 ---------
<S>                                              <C>
         310(a)                                  4.1(a)
         310(b)                                  4.1(c), 2.8
         310(c)                                  Inapplicable
         311(a)                                  2.2(b)
         311(b)                                  2.2(b)
         311(c)                                  Inapplicable
         312(a)                                  2.2(a)
         312(b)                                  2.2(b)
         313                                     2.3
         314(a)                                  2.4
         314(b)                                  Inapplicable
         314(c)                                  2.5
         314(d)                                  Inapplicable
         314(e)                                  1.1, 2.5, 3.2
         314(f)                                  2.1, 3.2
         315(a)                                  3.1(d)
         315(b)                                  2.7
         315(c)                                  3.1
         315(d)                                  3.1(d)
         316(a)                                  1.1, 3.6, 5.4
         316(b)                                  5.3
         316(c)                                  8.2
         317(a)                                  Inapplicable
         317(b)                                  Inapplicable
         318(a)                                  2.1(b)
         318(b)                                  2.1
         318(c)                                  2.1(a)
</TABLE>


                                      iii

<PAGE>


                    PREFERRED SECURITIES GUARANTEE AGREEMENT

          THIS GUARANTEE AGREEMENT (the "Preferred Securities Guarantee"), dated
as of ______________, 2001 is executed and delivered by Spectrum Bancorporation,
Inc., an Iowa corporation (the "Guarantor"), and Wilmington Trust Company, as
trustee (the "Preferred Guarantee Trustee"), for the benefit of the Holders (as
defined herein) from time to time of the Preferred Securities (as defined
herein) of Spectrum Capital Trust II, a Delaware statutory business trust
("Spectrum Capital").

          WHEREAS, pursuant to an Amended and Restated Trust Agreement (the
"Trust Agreement") dated as of ______________, 2001 among the trustees of
Spectrum Capital named therein, the Guarantor, as sponsor, and the holders from
time to time of undivided beneficial interests in the assets of Spectrum
Capital, Spectrum Capital is issuing on the date hereof ______________ preferred
securities, and within 30 days after the date of the prospectus relating to the
public offering of the preferred securities, a possible additional amount of up
to _____________ preferred securities pursuant to an underwriters'
over-allotment option, having an aggregate liquidation amount of $______________
to $_____________, designated the _____% Cumulative Preferred Securities (the
"Preferred Securities"); and

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

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

                                    ARTICLE I
                         DEFINITIONS AND INTERPRETATION

          SECTION 1.1 DEFINITIONS AND INTERPRETATION. In this Preferred
Securities Guarantee, unless the context otherwise requires:

          (a)  capitalized terms used in this Preferred Securities 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 Preferred Securities Guarantee
          has the same meaning throughout;


<PAGE>

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

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

          (e)  a term defined in the Trust Indenture Act has the same meaning
          when used in this Preferred Securities Guarantee, unless otherwise
          defined in this Preferred Securities Guarantee or unless the context
          otherwise requires; and

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

          "Affiliate" has the same meaning as given to that term in Rule 405 of
the Securities Act of 1933, as amended, or any successor rule thereunder.

          "Business Day" means any day other than (a) a Saturday or Sunday, (b)
a day on which banking institutions in the State of Iowa are authorized or
required by law or executive order to remain closed, or (c) a day on which the
Preferred Guarantee Trustee's Corporate Trust Office is closed for business.

          "Corporate Trust Office" means the office of the Preferred Guarantee
Trustee at which the corporate trust business of the Preferred Guarantee Trustee
shall, at any particular time, be principally administered, which office at the
date of execution of this Agreement is located at Rodney Square North, 1100
North Market Street, Wilmington, Delaware 19890-0001, Attn: Corporate Trust
Administration.

          "Covered Person" means any Holder or beneficial owner of Preferred
Securities.

          "Debt" means with respect to any person, whether recourse is to all or
a portion of the assets of such person and whether or not contingent: (i) every
obligation of such person for money borrowed; (ii) every obligation of such
person evidenced by bonds, debentures, notes or other similar instruments,
including obligations incurred in connection with the acquisition of property,
assets or businesses; (iii) every reimbursement obligation of such person with
respect to letters of credit, bankers' acceptances or similar facilities issued
for the account of such person; (iv) every obligation of such person issued or
assumed as the deferred purchase price of property or services (but excluding
trade accounts payable or accrued liabilities arising in the ordinary course of
business); (v) every capital lease obligation of such person; and (vi) every
obligation of the type referred to in clauses (i) through (v) of another person
and all dividends of another person the payment of which, in either case, such
person has guaranteed or for which such person is responsible or liable,
directly or indirectly, as obligor or otherwise.


<PAGE>

          "Event of Default" means a default by the Guarantor on any of its
payment or other obligations under this Preferred Securities Guarantee.

          "Guarantee Payments" means the following payments or distributions,
without duplication, with respect to the Preferred Securities, to the extent not
paid or made by Spectrum Capital: (i) any accrued and unpaid Distributions (as
defined in the Trust Agreement) that are required to be paid on such Preferred
Securities to the extent Spectrum Capital shall have funds available therefor,
(ii) the redemption price, including all accrued and unpaid Distributions to the
date of redemption (the "Redemption Price") to the extent Spectrum Capital has
funds available therefor, with respect to any Preferred Securities called for
redemption by Spectrum Capital, and (iii) upon a voluntary or involuntary
dissolution, winding-up or termination of Spectrum Capital (other than in
connection with the distribution of Junior Subordinated Debentures to the
Holders in exchange for Preferred Securities as provided in the Trust
Agreement), the lesser of (a) the aggregate of the liquidation amount and all
accrued and unpaid Distributions on the Preferred Securities to the date of
payment, to the extent Spectrum Capital shall have funds available therefor, and
(b) the amount of assets of Spectrum Capital remaining available for
distribution to Holders in liquidation of Spectrum Capital (in either case, the
"Liquidation Distribution").

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

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

          "Indenture" means the Subordinated Indenture dated as of
______________, 2001, among the Guarantor (the "Debenture Issuer") and
Wilmington Trust Company, as trustee, and any indenture supplemental thereto
pursuant to which the Junior Subordinated Debentures are to be issued to the
Property Trustee (as defined in the Trust Agreement) of Spectrum Capital.

          "Junior Subordinated Debentures" means the series of junior
subordinated deferrable interest debt securities of the Guarantor designated the
_____% Junior Subordinated Debentures due 2031 held by the Property Trustee of
Spectrum Capital.

          "Majority in liquidation amount of the Preferred Securities" means,
except as provided by the Trust Indenture Act, a vote by Holders of Preferred
Securities, voting separately as a class, of more than 50% of the liquidation
amount (including the stated amount that would be paid on redemption,
liquidation or otherwise, plus accrued and


<PAGE>

unpaid Distributions to the date upon which the voting percentages are
determined) of all Preferred Securities.

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

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

          (b)  a brief statement of the nature and scope of the examination or
          investigation undertaken by each officer in rendering the Officers'
          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.

          "Preferred Guarantee Trustee" means Wilmington Trust Company, until a
Successor Preferred Guarantee Trustee has been appointed and has accepted such
appointment pursuant to the terms of this Preferred Securities Guarantee and
thereafter means each such Successor Preferred Guarantee Trustee.

          "Responsible Officer" means, with respect to the Preferred Guarantee
Trustee, any officer within the Corporate Trust Office of the Preferred
Guarantee Trustee, including any vice-president, any assistant vice-president,
any assistant secretary, the treasurer, any assistant treasurer or other officer
of the Corporate Trust Office of the Preferred Guarantee Trustee customarily
performing functions similar to those performed by any of the above designated
officers and also means, 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 Preferred Guarantee Trustee" means a successor Preferred
Guarantee Trustee possessing the qualifications to act as Preferred Guarantee
Trustee under Section 4.1.


<PAGE>

          "Senior and Subordinated Debt" means the principal of (and premium, if
any) and interest, if any (including interest accruing on or after the filing of
any petition in bankruptcy or for reorganization relating to the Guarantor
whether or not such claim for post-petition interest is allowed in such
proceeding), on Debt of the Guarantor, whether incurred on or prior to the date
of the Indenture or thereafter incurred, unless, in the instrument creating or
evidencing the same or pursuant to which the same is outstanding, it is provided
that such obligations are not superior in right of payment to the Preferred
Securities Guarantee or to other Debt which is pari passu with, or subordinated
to, the Preferred Securities Guarantee; provided, however, that Senior and
Subordinated Debt shall not be deemed to include (i) any Debt of the Guarantor
which when incurred and without respect to any election under section 1111(b) of
the United States Bankruptcy Code of 1978, as amended, was without recourse to
the Guarantor, (ii) any Debt of the Guarantor to any of its subsidiaries, (iii)
any Debt to any employee of the Guarantor, (iv) any Debt which by its terms is
subordinated to trade accounts payable or accrued liabilities arising in the
ordinary course of business to the extent that payments made to the holders of
such Debt by the holders of the Junior Subordinated Debentures as a result of
the subordination provisions of the Indenture would be greater than they
otherwise would have been as a result of any obligation of such holders to pay
amounts over to the obligees on such trade accounts payable or accrued
liabilities arising in the ordinary course of business as a result of the
subordination provisions to which such Debt is subject, (v) the Junior
Subordinated Debentures, and (vi) any other debt securities issued pursuant to
the Indenture.

          "Trust Indenture Act" means the Trust Indenture Act of 1939, as
amended.

                                   ARTICLE II
                               TRUST INDENTURE ACT

SECTION 2.1  TRUST INDENTURE ACT; APPLICATION.

          (a)  This Preferred Securities Guarantee is subject to the provisions
          of the Trust Indenture Act that are required to be part of this
          Preferred Securities Guarantee and shall, to the extent applicable, be
          governed by such provisions; and

          (b)  If and to the extent that any provision of this Preferred
          Securities Guarantee limits, qualifies or conflicts with the duties
          imposed by Sections 310 to 317, inclusive, of the Trust Indenture Act,
          such imposed duties shall control.

SECTION 2.2  LISTS OF HOLDERS OF SECURITIES.

          (a)  The Guarantor shall provide the Preferred Guarantee Trustee with
          a list, in such form as the Preferred Guarantee Trustee may reasonably
          require, of the names and addresses of the Holders of the Preferred
          Securities ("List of Holders") (i) on or before January 15 and July 15
          of each year, and (ii) at any


<PAGE>

          other time within 30 days of receipt by the Guarantor of a written
          request for a List of Holders, as of a date no more than 14 days
          before such List of Holders is given to the Preferred Guarantee
          Trustee provided, that the Guarantor shall not be obligated to provide
          such List of Holders at any time the List of Holders does not differ
          from the most recent List of Holders given to the Preferred Guarantee
          Trustee by the Guarantor. The Preferred Guarantee Trustee may destroy
          any List of Holders previously given to it on receipt of a new List of
          Holders.

          (b)  The Preferred Guarantee Trustee shall comply with its obligations
          under Sections 311(a), 311(b) and Section 312(b) of the Trust
          Indenture Act.

          SECTION 2.3 REPORTS BY THE PREFERRED GUARANTEE TRUSTEE. On or before
July 15 of each year, the Preferred Guarantee Trustee shall provide to the
Holders of the Preferred Securities such reports as are required by Section 313
of the Trust Indenture Act, if any, in the form and in the manner provided by
Section 313 of the Trust Indenture Act. The Preferred Guarantee Trustee shall
also comply with the requirements of Section 313(d) of the Trust Indenture Act.

          SECTION 2.4 PERIODIC REPORTS TO PREFERRED GUARANTEE TRUSTEE. The
Guarantor shall provide to the Preferred Guarantee Trustee such documents,
reports and information as required by Section 314 of the Trust Indenture Act,
if any, and the compliance certificate required by Section 314 of the Trust
Indenture Act in the form, in the manner and at the times required by Section
314 of the Trust Indenture Act.

          SECTION 2.5 EVIDENCE OF COMPLIANCE WITH CONDITIONS PRECEDENT. The
Guarantor shall provide to the Preferred Guarantee Trustee such evidence of
compliance with the conditions precedent, if any, provided for in this Preferred
Securities Guarantee that relate to any of the matters set forth in Section
314(c) of the Trust Indenture Act. Any certificate or opinion required to be
given by an officer pursuant to Section 314(c)(1) may be given in the form of an
Officers' Certificate.

          SECTION 2.6 EVENTS OF DEFAULT; WAIVER. The Holders of a Majority in
liquidation amount of Preferred Securities may, by vote, on behalf of the
Holders of all of the Preferred Securities, waive any past Event of Default and
its consequences. Upon such waiver, any such Event of Default shall cease to
exist, and any Event of Default arising therefrom shall be deemed to have been
cured, for every purpose of this Preferred Securities Guarantee, but no such
waiver shall extend to any subsequent or other default or Event of Default or
impair any right consequent thereon.

          SECTION 2.7 EVENT OF DEFAULT; NOTICE.

          (a)  The Preferred Guarantee Trustee shall, within 90 days after the
          occurrence of an Event of Default, transmit by mail, first class
          postage prepaid,


<PAGE>

          to the Holders of the Preferred Securities, notices of all Events of
          Default actually known to a Responsible Officer of the Preferred
          Guarantee Trustee, unless such defaults have been cured before the
          giving of such notice, provided, that, the Preferred Guarantee Trustee
          shall be protected in withholding such notice if and so long as a
          Responsible Officer of the Preferred Guarantee Trustee in good faith
          determines that the withholding of such notice is in the interests of
          the Holders of the Preferred Securities.

          (b)  The Preferred Guarantee Trustee shall not be deemed to have
          knowledge of any Event of Default unless the Preferred Guarantee
          Trustee shall have received a properly addressed written notice, or of
          which a Responsible Officer of the Preferred Guarantee Trustee charged
          with the administration of the Trust Agreement shall have obtained
          actual knowledge.

          SECTION 2.8 CONFLICTING INTERESTS. The Trust Agreement shall be deemed
to be specifically described in this Preferred Securities Guarantee for the
purposes of clause (i) of the first proviso contained in Section 310(b) of the
Trust Indenture Act.

                                   ARTICLE III
                          POWERS, DUTIES AND RIGHTS OF
                           PREFERRED GUARANTEE TRUSTEE

          SECTION 3.1 POWERS AND DUTIES OF THE PREFERRED GUARANTEE TRUSTEE.

          (a)  This Preferred Securities Guarantee shall be held by the
          Preferred Guarantee Trustee for the benefit of the Holders of the
          Preferred Securities, and the Preferred Guarantee Trustee shall not
          transfer this Preferred Securities Guarantee to any Person except a
          Holder of Preferred Securities exercising such Holder's rights
          pursuant to Section 5.4(b) or to a Successor Preferred Guarantee
          Trustee on acceptance by such Successor Preferred Guarantee Trustee of
          its appointment to act as Successor Preferred Guarantee Trustee. The
          right, title and interest of the Preferred Guarantee Trustee shall
          automatically vest in any Successor Preferred 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 Preferred Guarantee Trustee.

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


<PAGE>

          (c)  The Preferred Guarantee Trustee, before the occurrence of any
          Event of Default and after the curing of all Events of Default that
          may have occurred, shall undertake to perform only such duties as are
          specifically set forth in this Preferred Securities Guarantee, and no
          implied covenants shall be read into this Preferred Securities
          Guarantee against the Preferred Guarantee Trustee. In case an Event of
          Default has occurred (that has not been cured or waived pursuant to
          Section 2.6) and is actually known to a Responsible Officer of the
          Preferred Guarantee Trustee, the Preferred Guarantee Trustee shall
          exercise such of the rights and powers vested in it by this Preferred
          Securities 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 such person's own affairs.

          (d)  No provision of this Preferred Securities Guarantee shall be
          construed to relieve the Preferred 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 Preferred Guarantee
               Trustee shall be determined solely by the express provisions of
               this Preferred Securities Guarantee, and the Preferred Guarantee
               Trustee shall not be liable except for the performance of such
               duties and obligations as are specifically set forth in this
               Preferred Securities Guarantee, and no implied covenants or
               obligations shall be read into this Preferred Securities
               Guarantee against the Preferred Guarantee Trustee; and

               (B)  in the absence of bad faith on the part of the Preferred
               Guarantee Trustee, the Preferred 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 Preferred Guarantee
               Trustee and conforming to the requirements of this Preferred
               Securities Guarantee; but in the case of any such certificates or
               opinions that by any provision hereof are specifically required
               to be furnished to the Preferred Guarantee Trustee, the Preferred
               Guarantee Trustee shall be under a duty to examine the same to
               determine whether or not they conform to the requirements of this
               Preferred Securities Guarantee;

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


<PAGE>

               (iii) the Preferred 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 direction of the Holders of not less
               than a Majority in liquidation amount of the Preferred Securities
               relating to the time, method and place of conducting any
               proceeding for any remedy available to the Preferred Guarantee
               Trustee, or exercising any trust or power conferred upon the
               Preferred Guarantee Trustee under this Preferred Securities
               Guarantee; and

               (iv) no provision of this Preferred Securities Guarantee shall
               require the Preferred 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 Preferred Guarantee Trustee shall have
               reasonable grounds for believing that the repayment of such funds
               or liability is not reasonably assured to it under the terms of
               this Preferred Securities Guarantee or indemnity, reasonably
               satisfactory to the Preferred Guarantee Trustee, against such
               risk or liability is not reasonably assured to it.

          SECTION 3.2 CERTAIN RIGHTS OF PREFERRED GUARANTEE TRUSTEE.

          (a)  Subject to the provisions of Section 3.1:

          (i)  The Preferred Guarantee Trustee may conclusively rely upon, 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
          Preferred Securities Guarantee shall be sufficiently evidenced by an
          Officers' Certificate.

          (iii) Whenever, in the administration of this Preferred Securities
          Guarantee, the Preferred Guarantee Trustee shall deem it desirable
          that a matter be proved or established before taking, suffering or
          omitting any action hereunder, the Preferred 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
          Officers' Certificate which, upon receipt of such request, shall be
          promptly delivered by the Guarantor.

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


<PAGE>

          (v)  The Preferred Guarantee Trustee may consult with counsel, and the
          written 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 Preferred Guarantee Trustee shall
          have the right at any time to seek instructions concerning the
          administration of this Preferred Securities Guarantee from any court
          of competent jurisdiction.

          (vi) The Preferred Guarantee Trustee shall be under no obligation to
          exercise any of the rights or powers vested in it by this Preferred
          Securities Guarantee at the request or direction of any Holder, unless
          such Holder shall have provided to the Preferred Guarantee Trustee
          such security and indemnity, reasonably satisfactory to the Preferred
          Guarantee Trustee, against the costs, expenses (including attorneys'
          fees and expenses and the expenses of the Preferred 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
          Preferred Guarantee Trustee; provided that, nothing contained in this
          Section 3.2(a)(vi) shall be taken to relieve the Preferred Guarantee
          Trustee, upon the occurrence of an Event of Default, of its obligation
          to exercise the rights and powers vested in it by this Preferred
          Securities Guarantee.

          (vii) The Preferred 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 Preferred Guarantee
          Trustee, in its discretion, may make such further inquiry or
          investigation into such facts or matters as it may see fit.

          (viii) The Preferred 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
          Preferred 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 Preferred Guarantee Trustee or its agents
          hereunder shall bind the Holders of the Preferred Securities, and the
          signature of the Preferred Guarantee Trustee or its agents alone shall
          be sufficient and effective to perform any such action. No third party
          shall be required to inquire as to the authority of the Preferred
          Guarantee Trustee to so act or as to its compliance with any of the
          terms and provisions of this Preferred Securities


<PAGE>

          Guarantee, both of which shall be conclusively evidenced by the
          Preferred Guarantee Trustee's or its agent's taking such action.

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

          (b)  No provision of this Preferred Securities Guarantee shall be
          deemed to impose any duty or obligation on the Preferred 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 Preferred 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
          Preferred Guarantee Trustee shall be construed to be a duty.

          SECTION 3.3 NOT RESPONSIBLE FOR RECITALS OR ISSUANCE OF GUARANTEE. The
recitals contained in this Preferred Securities Guarantee shall be taken as the
statements of the Guarantor, and the Preferred Guarantee Trustee does not assume
any responsibility for their correctness. The Preferred Guarantee Trustee makes
no representation as to the validity or sufficiency of this Preferred Securities
Guarantee.

                                   ARTICLE IV
                           PREFERRED GUARANTEE TRUSTEE

          SECTION 4.1 PREFERRED GUARANTEE TRUSTEE; ELIGIBILITY.

          (a)  There shall at all times be a Preferred 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 a corporation or Person
               permitted by the Securities and Exchange Commission to act as an
               institutional trustee under the Trust Indenture Act, authorized
               under such laws to exercise corporate trust powers, having a
               combined capital and surplus of at least $50,000,000, and subject
               to supervision or examination by federal, state, territorial or
               District of Columbia authority. If such corporation publishes


<PAGE>

               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 4.1(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 Preferred Guarantee Trustee shall cease to be
          eligible to so act under Section 4.1(a), the Preferred Guarantee
          Trustee shall immediately resign in the manner and with the effect set
          out in Section 4.2(c).

          (c)  If the Preferred Guarantee Trustee has or shall acquire any
          "conflicting interest" within the meaning of Section 310(b) of the
          Trust Indenture Act, the Preferred Guarantee Trustee and Guarantor
          shall in all respects comply with the provisions of Section 310(b) of
          the Trust Indenture Act.

          SECTION 4.2 APPOINTMENT, REMOVAL AND RESIGNATION OF PREFERRED
GUARANTEE TRUSTEES.

          (a)  Subject to Section 4.2(b), the Preferred Guarantee Trustee may be
          appointed or removed without cause at any time by the Guarantor.

          (b)  The Preferred Guarantee Trustee shall not be removed in
          accordance with Section 4.2(a) until a Successor Preferred Guarantee
          Trustee has been appointed and has accepted such appointment by
          written instrument executed by such Successor Preferred Guarantee
          Trustee and delivered to the Guarantor.

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

          (d)  If no Successor Preferred Guarantee Trustee shall have been
          appointed and accepted appointment as provided in this Section 4.2
          within 60 days after delivery to the Guarantor of an instrument of
          resignation, the resigning Preferred Guarantee Trustee may petition
          any court of competent jurisdiction for appointment of a Successor
          Preferred Guarantee Trustee. Such court may thereupon, after
          prescribing such notice, if any, as it may deem proper, appoint a
          Successor Preferred Guarantee Trustee.


<PAGE>

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

          (f)  Upon termination of this Preferred Securities Guarantee or
          removal or resignation of the Preferred Guarantee Trustee pursuant to
          this Section 4.2, the Guarantor shall pay to the Preferred Guarantee
          Trustee all amounts accrued to the date of such termination, removal
          or resignation.

                                    ARTICLE V
                                    GUARANTEE

          SECTION 5.1 GUARANTEE. The Guarantor irrevocably and unconditionally
agrees to pay in full to the Holders the Guarantee Payments (without duplication
of amounts theretofore paid by Spectrum Capital), as and when due, regardless of
any defense, right of set-off or counterclaim that Spectrum Capital 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 Spectrum Capital to pay such amounts to the Holders.

          SECTION 5.2 WAIVER OF NOTICE AND DEMAND. The Guarantor hereby waives
notice of acceptance of this Preferred Securities Guarantee and of any liability
to which it applies or may apply, presentment, demand for payment, any right to
require a proceeding first against Spectrum Capital 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 5.3 OBLIGATIONS NOT AFFECTED. The obligations, covenants,
agreements and duties of the Guarantor under this Preferred Securities 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 Spectrum Capital of any express or
          implied agreement, covenant, term or condition relating to the
          Preferred Securities to be performed or observed by Spectrum Capital;

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


<PAGE>

          (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
          Preferred Securities, or any action on the part of Spectrum Capital
          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,
          Spectrum Capital or any of the assets of Spectrum Capital;

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

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

          (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 5.3 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 5.4 RIGHTS OF HOLDERS.

          (a)  The Holders of a Majority in liquidation amount of the Preferred
          Securities have the right to direct the time, method and place of
          conducting of any proceeding for any remedy available to the Preferred
          Guarantee Trustee in respect of this Preferred Securities Guarantee or
          exercising any trust or power conferred upon the Preferred Guarantee
          Trustee under this Preferred Securities Guarantee.

          (b)  Any Holder of Preferred Securities may institute a legal
          proceeding directly against the Guarantor to enforce its rights under
          this Preferred Securities Guarantee, without first instituting a legal
          proceeding against Spectrum Capital, the Preferred Guarantee Trustee
          or any other Person.

          SECTION 5.5 GUARANTEE OF PAYMENT. This Preferred Securities Guarantee
creates a Guarantee of payment and not of collection.

          SECTION 5.6 SUBROGATION. The Guarantor shall be subrogated to all (if
any) rights of the Holders of Preferred Securities against Spectrum Capital in
respect of any amounts paid to such Holders by the Guarantor under this
Preferred Securities


<PAGE>

Guarantee; provided, however, that the Guarantor shall not (except to the extent
required by mandatory 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 Preferred
Securities Guarantee, if, at the time of any such payment, any amounts are due
and unpaid under this Preferred Securities 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.

          SECTION 5.7 INDEPENDENT OBLIGATIONS. The Guarantor acknowledges that
its obligations hereunder are independent of the obligations of Spectrum Capital
with respect to the Preferred Securities, and that the Guarantor shall be liable
as principal and as debtor hereunder to make Guarantee Payments pursuant to the
terms of this Preferred Securities Guarantee notwithstanding the occurrence of
any event referred to in subsections (a) through (g), inclusive, of Section 5.3.

                                   ARTICLE VI
                    LIMITATION OF TRANSACTIONS; SUBORDINATION

          SECTION 6.1 LIMITATION OF TRANSACTIONS. So long as any Preferred
Securities remain outstanding, if there shall have occurred and be continuing an
Event of Default or an event of default under the Trust Agreement, then (a) the
Guarantor shall not declare or pay any dividend or distributions on, or redeem,
purchase, acquire, or make a liquidation payment with respect to, any of its
capital stock, (b) the Guarantor shall not make any payment of interest,
principal or premium, if any, on or repay, repurchase or redeem any debt
securities issued by the Guarantor (including other Junior Subordinated
Debentures) which rank pari passu with or junior in interest to the Junior
Subordinated Debentures or (c) the Guarantor shall not make any guarantee
payments with respect to any guarantee by the guarantor of the debt securities
of any subsidiary of the Guarantor if such guarantee ranks pari passu or junior
in interest to the Junior Subordinated Debentures (other than (a) dividends or
distributions in common stock, (b) any declaration of a dividend in connection
with the implementation of a shareholders' rights plan, or the issuance of stock
under any such plan in the future or the redemption or repurchase of any such
rights pursuant thereto, (c) payments under this Preferred Securities Guarantee
and (d) purchases of common stock related to the issuances of common stock or
rights under any of the Guarantor's benefit plans for its directors, officers or
employees).

          SECTION 6.2 RANKING. This Preferred Securities Guarantee will
constitute an unsecured obligation of the Guarantor and will rank subordinate
and junior in right of payment to all Senior and Subordinated Debt of the
Guarantor.


<PAGE>

                                   ARTICLE VII
                                   TERMINATION

          SECTION 7.1 TERMINATION. This Preferred Securities Guarantee shall
terminate upon (i) full payment of the Redemption Price of all Preferred
Securities, (ii) upon full payment of the amounts payable in accordance with the
Trust Agreement upon liquidation of Spectrum Capital or (iii) upon distribution
of the Junior Subordinated Debentures to the Holders of the Preferred
Securities. Notwithstanding the foregoing, this Preferred Securities Guarantee
will continue to be effective or will be reinstated, as the case may be, if at
any time any Holder of Preferred Securities must restore payment of any sums
paid under the Preferred Securities or under this Preferred Securities
Guarantee.

                                  ARTICLE VIII
                                 INDEMNIFICATION

          SECTION 8.1 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 Preferred Securities Guarantee and in a manner
          that such Indemnified Person reasonably believed to be within the
          scope of the authority conferred on such Indemnified Person by this
          Preferred Securities 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 Guarantor and upon such information,
          opinions, reports or statements presented to 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
          has been selected with reasonable care by or on behalf of the
          Guarantor, 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 Preferred Securities might
          properly be paid.

          SECTION 8.2 INDEMNIFICATION. The Guarantor agrees to indemnify each
Indemnified Person for, and to hold each Indemnified Person harmless against,
any loss, liability or expense incurred without negligence or bad faith on its
part, arising out of or in connection with the acceptance or administration of
the trust or trusts hereunder, including the costs and expenses (including
reasonable legal fees and expenses) of defending itself against, or
investigating, any claim or liability in connection with the exercise or
performance of any of its powers or duties hereunder. The obligation to


<PAGE>

indemnify as set forth in this Section 8.2 shall survive the termination of this
Preferred Securities Guarantee.

                                   ARTICLE IX
                                  MISCELLANEOUS

          SECTION 9.1 SUCCESSORS AND ASSIGNS. All guaranties and agreements
contained in this Preferred Securities Guarantee shall bind the successors,
assigns, receivers, trustees and representatives of the Guarantor and shall
inure to the benefit of the Holders of the Preferred Securities then
outstanding.

          SECTION 9.2 AMENDMENTS. Except with respect to any changes that do not
materially adversely affect the rights of Holders (in which case no consent of
Holders will be required), this Preferred Securities Guarantee may only be
amended with the prior approval of the Holders of at least a Majority in
liquidation amount of the Preferred Securities. The provisions of Article VI of
the Trust Agreement with respect to meetings of Holders of the Securities apply
to the giving of such approval.

          SECTION 9.3 NOTICES. All notices provided for in this Preferred
Securities Guarantee shall be in writing, duly signed by the party giving such
notice, and shall be delivered, telecopied or mailed by registered or certified
mail, as follows:

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

                    Wilmington Trust Company
                    Rodney Square North 1100 North Market Street
                    Wilmington, DE  19890-0001
                    Attention: Corporate Trust Administration

          (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 Preferred Securities):

                    Spectrum Bancorporation, Inc.
                    10834 Old Mill Road, Suite One
                    Omaha, Nebraska, 68154-2648
                    Attention: President

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


<PAGE>

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 9.4 BENEFIT. This Preferred Securities Guarantee is solely for
the benefit of the Holders of the Preferred Securities and, subject to Section
3.1(a), is not separately transferable from the Preferred Securities.

          SECTION 9.5. GOVERNING LAW. THIS PREFERRED SECURITIES GUARANTEE SHALL
BE GOVERNED BY, AND CONSTRUED AND INTERPRETED IN ACCORDANCE WITH, THE LAWS OF
THE STATE OF IOWA; PROVIDED THAT THE IMMUNITIES AND THE STANDARD OF CARE OF THE
TRUSTEE SHALL BE GOVERNED BY DELAWARE LAW.

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

                                        SPECTRUM BANCORPORATION, INC.,
                                        As Guarantor


                                   By:
                                        ----------------------------------------
                                        Name:
                                              ----------------------------------
                                        Title:
                                              ----------------------------------


                                        WILMINGTON TRUST COMPANY,
                                        As Preferred Guarantee Trustee


                                   By;
                                        ----------------------------------------
                                        Name:
                                              ----------------------------------
                                        Title:
                                              ----------------------------------