<PAGE>

                                                                     Exhibit 4.8


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                   PREFERRED SECURITIES GUARANTEE AGREEMENT


                                by and between



                             PRIVATEBANCORP, INC.


                                      and


                           WILMINGTON TRUST COMPANY



                        Dated as of ____________, 2001





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<PAGE>

                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                            Page No.
<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 Guarantee Trustee............................................   5
     Section 2.4    Periodic Reports to Guarantee Trustee.......................................   5
     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.......................................................   6

ARTICLE III
     POWERS, DUTIES AND RIGHTS OF GUARANTEE TRUSTEE.............................................   7
     Section 3.1    Powers and Duties of the Guarantee Trustee..................................   7
     Section 3.2    Certain Rights of Guarantee Trustee.........................................   8
     Section 3.3    Not Responsible for Recitals or Issuance of Guarantee.......................  10

ARTICLE IV
     GUARANTEE TRUSTEE..........................................................................  10
     Section 4.1    Guarantee Trustee; Eligibility..............................................  10
     Section 4.2    Appointment, Removal and Resignation of Guarantee Trustee...................  11

ARTICLE V
     GUARANTEE..................................................................................  11
     Section 5.1    Guarantee...................................................................  11
     Section 5.2    Waiver of Notice and Demand.................................................  12
     Section 5.3    Obligations not Affected....................................................  12
     Section 5.4    Rights of Holders...........................................................  13
     Section 5.5    Guarantee of Payment........................................................  13
     Section 5.6    Subrogation.................................................................  13
     Section 5.7    Independent Obligations.....................................................  13

ARTICLE VI
     LIMITATION OF TRANSACTIONS; SUBORDINATION..................................................  14
     Section 6.1    Limitation of Transactions..................................................  14
     Section 6.2    Ranking.....................................................................  14
</TABLE>

                                       i
<PAGE>

<TABLE>
<S>                                                                                               <C>
ARTICLE VII
     TERMINATION................................................................................  14
     Section 7.1    Termination.................................................................  14

ARTICLE VIII
     INDEMNIFICATION............................................................................  15
     Section 8.1    Exculpation.................................................................  15
     Section 8.2    Indemnification.............................................................  15

ARTICLE IX
     MISCELLANEOUS..............................................................................  15
     Section 9.1    Successors and Assigns......................................................  15
     Section 9.2    Amendments..................................................................  16
     Section 9.3    Notices.....................................................................  16
     Section 9.4    Benefit.....................................................................  17
     Section 9.5    Governing Law...............................................................  17
</TABLE>

                                      ii
<PAGE>

                             CROSS REFERENCE TABLE


          Section of Trust                                Section of
          Indenture Act of                                Guarantee
          1939, as amended                                Agreement
          ----------------                                ---------

          310(a)                                          4.1(a)
          310(b)                                          4.1(c), 2.8
          310(c)                                          Not Applicable
          311(a)                                          2.2(b)
          311(b)                                          2.2(b)
          311(c)                                          Not Applicable
          312(a)                                          2.2(a)
          312(b)                                          2.2(b)
          313                                             2.3
          314(a)                                          2.4
          314(b)                                          Not Applicable
          314(c)                                          2.5
          314(d)                                          Not Applicable
          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, 2.6, 5.4
          316(b)                                          5.3
          317(a)                                          3.1
          317(b)                                          Not Applicable
          318(a)                                          2.1(a)
          318(b)                                          2.1
          318(c)                                          2.1(b)

          Note: This Cross-Reference Table does not constitute part of this
          Agreement and shall not affect the interpretation of any of its terms
          or provisions.

                                      iii
<PAGE>

                   PREFERRED SECURITIES GUARANTEE AGREEMENT

     This PREFERRED SECURITIES GUARANTEE AGREEMENT (this "Preferred Securities
Guarantee"), dated as of___________, 2001, is executed and delivered by
PRIVATEBANCORP, INC., a Delaware corporation (the "Guarantor"), and WILMINGTON
TRUST COMPANY, a Delaware banking corporation organized under the laws of the
State of Delaware, as trustee (the "Guarantee Trustee"), for the benefit of the
Holders (as defined herein) from time to time of the Preferred Securities (as
defined herein) of PrivateBancorp Capital Trust I, a Delaware statutory business
trust (the "Trust").

                                   RECITALS

     WHEREAS, pursuant to an Amended and Restated Trust Agreement (the "Trust
Agreement"), dated as of ______________, 2001, among the trustees of the Trust
named therein, the Guarantor, as sponsor, and the holders from time to time of
undivided beneficial interests in the assets of the Trust, the Trust is issuing
on the date hereof up to 2,000,000 preferred securities, having an aggregate
Liquidation Amount of up to $20,000,000 designated the _____% Cumulative Trust
Preferred Securities;

     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) terms defined in the Trust Agreement as at the date of execution of
this Preferred Securities Guarantee have the same meaning when used in this
Preferred Securities Guarantee, unless otherwise defined in this Preferred
Securities Guarantee;

     (c) a term defined anywhere in this Preferred Securities Guarantee has the
same meaning throughout;
<PAGE>

     (d) 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;

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

     (f) 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

     (g) 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 Saturday, Sunday, a day on which
federal or state banking institutions in New York, New York are authorized or
required by law, executive order or regulation to close or a day on which the
Corporate Trust Office of the Guarantee Trustee is closed for business.

     "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
Agreement is located at Rodney Square North, 1100 North Market Street,
Wilmington, Delaware 19890-0001, Attention: Corporate Trust Administration.

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

     "Debentures" means the ____% Junior Subordinated Debentures due __________,
2031, of the Debenture Issuer held by the Property Trustee of the Trust.

     "Debenture Issuer" means PrivateBancorp, Inc., issuer of the Debentures
under the Indenture.

     "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 the Trust:  (i) any accrued and unpaid Distributions that are required
to be paid on such Preferred Securities, to the extent the Trust 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 the Trust has funds available therefor, with respect to any Preferred
Securities called for redemption by the Trust, and (iii) upon a voluntary or
involuntary dissolution, winding-up or termination of the Trust (other than in
connection with the distribution of Debentures to the Holders in exchange for
Preferred Securities

                                       2
<PAGE>

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 the Trust shall have funds
available therefor (the "Liquidation Distribution"), and (b) the amount of
assets of the Trust remaining available for distribution to Holders in
liquidation of the Trust.

     "Guarantee Trustee" means Wilmington Trust Company, until a Successor
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 Guarantee Trustee.

     "Guarantor" means PrivateBancorp, Inc., a Delaware corporation.

     "Holder" shall mean any holder, as registered on the books and records of
the Trust, 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, the Guarantee Trustee or any of their respective
Affiliates.

     "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 ______________, 2001, among the
Debenture Issuer and Wilmington Trust Company, as trustee, and any indenture
supplemental thereto pursuant to which the Debentures are to be issued to the
Property Trustee of the Trust.

     "Liquidation Amount" means the stated value of $10 per Preferred Security.

     "Liquidation Distribution" has the meaning provided therefor in the
definition of Guarantee Payments.

     "Majority in Liquidation Amount of the Preferred Securities" means the
holders of more than 50% of the Liquidation Amount of all of the Preferred
Securities.

     "Officers' Certificate" means, with respect to any Person, a certificate
signed by two authorized officers of such Person, at least one of whom shall be
the principal executive officer, principal financial officer, principal
accounting officer, treasurer or any vice president 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;

                                       3
<PAGE>

     (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 Securities" means the _____% Cumulative Trust Preferred
Securities representing undivided beneficial interests in the assets of the
Trust which rank pari passu with Common Securities issued by the Trust;
provided, however, that upon the occurrence of an Event of Default, the rights
of holders of Common Securities to payment in respect of distributions and
payments upon liquidation, redemption and otherwise are subordinated to the
rights of holders of Preferred Securities.

     "Redemption Price" has the meaning provided therefor in the definition of
Guarantee Payments.

     "Responsible Officer" means, with respect to the Guarantee Trustee, any
officer within the Corporate Trust Office of the Guarantee Trustee with direct
responsibility for the administration of this Preferred Securities Guarantee,
including any vice-president, any assistant vice-president, any assistant
secretary or other officer or assistant officer of the 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 Guarantee Trustee" means a successor Guarantee Trustee
possessing the qualifications to act as Guarantee Trustee under Section 4.1.

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

                                       4
<PAGE>

                                  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.

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

 Section 2.2   Lists of Holders of Securities.

     (a) In the event the Guarantee Trustee is not also acting in the capacity
of the Property Trustee under the Trust Agreement, the Guarantor shall cause to
be provided to the Guarantee Trustee with a list, in such form as the Guarantee
Trustee may reasonably require, of the names and addresses of the Holders of the
Preferred Securities ("List of Holders") as of the date (i) within one Business
Day after March 15, June 15, September 15 and December 15, and (ii) at any 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 15 days before such List of Holders is
given to the 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 caused to have been given to the
Guarantee Trustee by the Guarantor.  The Guarantee Trustee may destroy any List
of Holders previously given to it on receipt of a new List of Holders.

     (b) The 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 Guarantee Trustee.

     On or before July 31 of each year, commencing July 31, 2001, the 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 Guarantee
Trustee shall also comply with the requirements of Section 313(d) of the Trust
Indenture Act.

 Section 2.4   Periodic Reports to Guarantee Trustee.

     The Guarantor shall provide to the Guarantee Trustee such documents,
reports and information as required by Section 314 (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.

                                       5
<PAGE>

 Section 2.5   Evidence of Compliance with Conditions Precedent.

     The Guarantor shall provide to the Guarantee Trustee such evidence of
compliance with any 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 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 Preferred 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, that, except in the case of a
default by Guarantor on any of its payment obligations, 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 Preferred 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, or of which a Responsible Officer of the 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.

                                       6
<PAGE>

                                  ARTICLE III
                POWERS, DUTIES AND RIGHTS OF GUARANTEE TRUSTEE

 Section 3.1   Powers and Duties of the Guarantee Trustee.

     (a) This Preferred Securities Guarantee shall be held by the Guarantee
Trustee for the benefit of the Holders of the Preferred Securities, and the
Guarantee Trustee shall not transfer this Preferred Securities Guarantee to any
Person except a Holder of Preferred Securities exercising his or her rights
pursuant to Section 5.4(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 Preferred Securities Guarantee for the benefit of the Holders of
the Preferred Securities.

     (c) The 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 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 Guarantee Trustee,
the 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 his or her own affairs.

     (d) No provision of this Preferred Securities 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 Preferred Securities
     Guarantee, and the 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 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

                                       7
<PAGE>

     of the opinions expressed therein, upon any certificates or opinions
     furnished to the 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 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 Preferred Securities 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 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
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 Guarantee Trustee, or exercising
any trust or power conferred upon the Guarantee Trustee under this Preferred
Securities Guarantee; and

          (iv)   no provision of this Preferred Securities 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 or liability
is not reasonably assured to it under the terms of this Preferred Securities
Guarantee or indemnity, reasonably satisfactory to the Guarantee Trustee,
against such risk or liability is not reasonably assured to it.

 Section 3.2   Certain Rights of Guarantee Trustee.

     (a)  Subject to the provisions of Section 3.1:

          (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
Preferred Securities Guarantee shall be sufficiently evidenced by an Officers'
Certificate;

          (iii)  whenever, in the administration of this Preferred Securities
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
Officers' Certificate which, upon receipt of such request, shall be promptly
delivered by the Guarantor;

                                       8
<PAGE>

          (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, 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 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 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 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 that, nothing contained in
this Section 3.2(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 Preferred Securities 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)   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 Preferred Securities 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 Preferred Securities
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 (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

                                       9
<PAGE>

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 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 3.3   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 Preferred Securities Guarantee.


                                  ARTICLE IV
                               GUARANTEE TRUSTEE

 SECTION 4.1   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 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 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 Guarantee Trustee shall cease to be eligible to so
act under Section 4.1(a), the Guarantee Trustee shall immediately resign in the
manner and with the effect set out in Section 4.2(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 and Guarantor shall in all respects comply with the provisions
of Section 310(b) of the Trust Indenture Act.

                                       10
<PAGE>

 SECTION 4.2   APPOINTMENT, REMOVAL AND RESIGNATION OF GUARANTEE TRUSTEE.

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

     (b) The Guarantee Trustee shall not be removed in accordance with Section
4.2(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 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 4.2 within 60 days after
delivery to the Guarantor of an instrument of resignation, the resigning
Guarantee Trustee 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 Preferred Securities Guarantee or removal or
resignation of the Guarantee Trustee pursuant to this Section 4.2, the Guarantor
shall pay to the Guarantee Trustee all fees and expenses 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 the Trust), as and when due, regardless of any defense, right of set-off or
counterclaim that the Trust 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 Trust to pay such
amounts to the Holders.

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 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
the Trust 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 the Trust of any express or implied agreement,
covenant, term or condition relating to the Preferred Securities to be performed
or observed by the Trust;

     (b) the extension of time for the payment by the Trust 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 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 Preferred Securities, or
any action on the part of the Trust 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 Trust or any of the assets of the
Trust;

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

     (f) any failure or omission to receive any regulatory approval or consent
required in connection with the Preferred Securities (or the common equity
securities issued by the Trust), including the failure to receive any approval
of the Board of Governors of the Federal Reserve System required for the
redemption of the Preferred Securities;

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

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     (h) 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) Subject to Section 5.4(b), 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 Guarantee
Trustee in respect of this Preferred Securities Guarantee or exercising any
trust or power conferred upon the Guarantee Trustee under this Preferred
Securities Guarantee.

     (b) Any Holder of Preferred Securities may institute and prosecute a legal
proceeding directly against the Guarantor to enforce its rights under this
Preferred Securities Guarantee, without first instituting a legal proceeding
against the Trust, the 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 the Trust in respect of any amounts paid to such
Holders by the Guarantor under this Preferred Securities 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 the Trust 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 (h), inclusive, of Section 5.3 hereof.

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                                  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 an Event of Default under this Preferred Securities Guarantee, an event
of default under the Trust Agreement or during an Extended Interest Payment
Period (as defined in the Indenture), then (a) the Guarantor shall not declare
or pay any dividend on, make any distributions with respect to, or redeem,
purchase, acquire or make a liquidation payment with respect to, any of its
capital stock (other than as a result of a reclassification of its capital stock
for another class of its capital stock) and (b) the Guarantor shall not make any
payment of interest or principal on or repay, repurchase or redeem any debt
securities issued by the Guarantor which rank pari passu with or junior to the
Debentures other than payments under this Preferred Securities Guarantee.

 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 Debt, Subordinated Debt and Additional Senior Obligations, as defined in
the Indenture, of the Guarantor, to the extent and in the manner set forth in
the Indenture, and the applicable provisions of the Indenture will apply, in all
relevant respects, to the obligations of the Guarantor hereunder.


                                  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
the Trust, or (iii) upon distribution of the Debentures to the Holders of the
Preferred Securities.  Notwithstanding the foregoing, this Preferred Securities
Guarantee shall continue to be effective or shall 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.

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                                  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 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 guarantees 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.

                                       15
<PAGE>

 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 Preferred 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 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 Preferred Securities):

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

     (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):

               PrivateBancorp, Inc.
               Ten North Dearborn
               Chicago, Illinois  60602
               Attention:  Chief Financial Officer

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

     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.

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 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 DELAWARE.

     This Preferred Securities Guarantee is executed as of the day and year
first above written.

                                   PRIVATEBANCORP, INC., as Guarantor

                                   By:___________________________
                                   Its:__________________________


                                   WILMINGTON TRUST COMPANY,
                                       as Guarantee Trustee

                                   By:____________________________
                                   Its:___________________________

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