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                                                                EXHIBIT 10.15(a)

                        INVESTMENT SUB-ADVISORY AGREEMENT

      AGREEMENT MADE THIS 3rd day of October, 2001 by and between Nuveen
Institutional Advisory Corp., a Delaware corporation and a registered investment
adviser ("Manager"), and Security Capital Research & Management Incorporated, a
Delaware corporation and a registered investment adviser ("Sub-Adviser").

      WHEREAS, Manager serves as the investment manager for the Nuveen Real
Estate Income Fund (the "Fund"), a closed-end management investment company
registered under the Investment Company Act of 1940, as amended (the "1940 Act")
pursuant to an Investment Management Agreement between Manager and the Fund (as
such agreement may be modified from time to time, the "Management Agreement");
and

      WHEREAS, Manager desires to retain Sub-Adviser as its agent to furnish
investment advisory services for the Fund, upon the terms and conditions
hereafter set forth;

      NOW, THEREFORE, in consideration of the mutual covenants herein contained,
the parties hereto agree as follows:

      1. Appointment. Manager hereby appoints Sub-Adviser to provide certain
sub-investment advisory services to the Fund for the period and on the terms set
forth in this Agreement. Sub-Adviser accepts such appointments and agrees to
furnish the services herein set forth for the compensation herein provided.

      2. Services to be Performed. Subject always to the supervision of Fund's
Board of Trustees and the Manager, Sub-Adviser will furnish an investment
program in respect of, make investment decisions for, and place all orders for
the purchase and sale of securities for the Fund, all on behalf of the Fund. In
the performance of its duties, Sub-Adviser will satisfy its fiduciary duties to
the Fund, will monitor the Fund's investments, and will comply with the
provisions of Fund's Declaration of Trust and By-laws, as amended from time to
time, and the stated investment objectives, policies and restrictions of the
Fund. Manager will provide Sub-Adviser with current copies of the Fund's
Declaration of Trust, By-laws, prospectus and any amendments thereto, and any
objectives, policies or limitations not appearing therein as they may be
relevant to Sub-Adviser's performance under this Agreement. Sub-Adviser and
Manager will each make its officers and employees available to the other from
time to time at reasonable times to review investment policies of the Fund and
to consult with each other regarding the investment affairs of the Fund.
Sub-Adviser will report to the Board of Trustees and to Manager with respect to
the implementation of such program.

      Sub-Adviser is authorized to select the brokers or dealers that will
execute the purchases and sales of portfolio securities for the Fund, and is
directed to use its best efforts to obtain best execution, which includes most
favorable net results and execution of the Fund's orders, taking into account
all appropriate factors, including price, dealer spread or commission, size and
difficulty of the transaction and research or other services provided. It is
understood that the
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Sub-Adviser will not be deemed to have acted unlawfully, or to have breached a
fiduciary duty to the Fund, or be in breach of any obligation owing to the Fund
under this Agreement, or otherwise, solely by reason of its having caused the
Fund to pay a member of a securities exchange, a broker or a dealer a commission
for effecting a securities transaction for the Fund in excess of the amount of
commission another member of an exchange, broker or dealer would have charged if
the Sub-Adviser determined in good faith that the commission paid was reasonable
in relation to the brokerage or research services provided by such member,
broker or dealer, viewed in terms of that particular transaction or the
Sub-Adviser's overall responsibilities with respect to its accounts, including
the Fund, as to which it exercises investment discretion. In addition, if in the
judgment of the Sub-Adviser, the Fund would be benefited by supplemental
services, the Sub-Adviser is authorized to pay spreads or commissions to brokers
or dealers furnishing such services in excess of spreads or commissions which
another broker or dealer may charge for the same transaction, provided that the
Sub-Adviser determined in good faith that the commission or spread paid was
reasonable in relation to the services provided. The Sub-Adviser will properly
communicate to the officers and trustees of the Fund such information relating
to transactions for the Fund as they may reasonably request. In no instance will
portfolio securities be purchased from or sold to the Manager, Sub-Adviser or
any affiliated person of either the Fund, Manager, or Sub-Adviser, except as may
be permitted under the 1940 Act;

      Sub-Adviser further agrees that it:

      (a)   will use the same degree of skill and care in providing such
            services as it uses in providing services to fiduciary accounts for
            which it has investment responsibilities;

      (b)   will conform to all applicable Rules and Regulations of the
            Securities and Exchange Commission in all material respects and in
            addition will conduct its activities under this Agreement in
            accordance with any applicable regulations of any governmental
            authority pertaining to its investment advisory activities;

      (c)   will report regularly to Manager and to the Board of Trustees of the
            Fund and will make appropriate persons available for the purpose of
            reviewing with representatives of Manager and the Board of Trustees
            on a regular basis at reasonable times the management of the Fund,
            including, without limitation, review of the general investment
            strategies of the Fund, the performance of the Fund in relation to
            standard industry indices and general conditions affecting the
            marketplace and will provide various other reports from time to time
            as reasonably requested by Manager; and

      (d)   will prepare such books and records with respect to the Fund's
            securities transactions as requested by the Manager and will furnish
            Manager and Fund's Board of Trustees such periodic and special
            reports as the Board or Manager may reasonably request.

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      3. Expenses. During the term of this Agreement, Sub-Adviser will pay all
expenses incurred by it in connection with its activities under this Agreement
other than the cost of securities (including brokerage commission, if any)
purchased for the Fund.

      4. Compensation. For the services provided and the expenses assumed
pursuant to this Agreement, Manager will pay the Sub-Adviser, and the
Sub-Adviser agrees to accept as full compensation therefor, a portfolio
management fee equal to the portion specified below of the investment management
fee payable by the Fund to the Manager based on average daily net assets which
includes net assets attributable to Fund Preferred Shares and the principal
amount of borrowings pursuant to the Management Agreement, as the net amount of
such fee is reduced by the obligation of Manager to reimburse certain fees and
expenses to the Fund pursuant to an Expense Reimbursement Agreement of even date
herewith by and between the Fund and the Manager, as such agreement may be
modified from time to time:

<TABLE>
<CAPTION>
                                                               PERCENTAGE OF NET
              DAILY NET ASSETS                                  MANAGEMENT FEE
<S>                                                            <C>
              Up to $125 million                                     50.0%
              $125 million to $150 million                           47.5%
              $150 million to $175 million                           45.0%
              $175 million to $200 million                           42.5%
              $200 million and over                                  40.0%
</TABLE>

The portfolio management fee shall accrue on each calendar day, and shall be
payable monthly on the first business day of the next succeeding calendar month.
The daily fee accrual shall be computed by multiplying the fraction of one
divided by the number of days in the calendar year by the applicable annual rate
of fee, and multiplying this product by the net assets of the Fund, determined
in the manner established by the Fund's Board of Trustees, as of the close of
business on the last preceding business day on which the Fund's net asset value
was determined.

For the month and year in which this Agreement becomes effective or terminates,
there shall be an appropriate proration on the basis of the number of days that
the Agreement is in effect during the month and year, respectively.

      5. Services to Others. Manager understands, and has advised Fund's Board
of Trustees, that Sub-Adviser now acts, or may in the future act, as an
investment adviser to fiduciary and other managed accounts, and as investment
adviser or sub-investment adviser to one other investment company that is not a
series of the Fund, provided that whenever the Fund and one or more other
investment advisory clients of Sub-Adviser have available funds for investment,
investments suitable and appropriate for each will be allocated in a manner
believed by Sub-Adviser to be equitable to each. Manager recognizes, and has
advised Fund's Board of Trustees, that in some cases this procedure may
adversely affect the size of the position that the Fund may obtain in a
particular security. It is further agreed that, on occasions when the
Sub-Adviser deems the purchase or sale of a security to be in the best interests
of the Fund as well as other accounts, it may, to the extent permitted by
applicable law, but will not be obligated to, aggregate

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the securities to be so sold or purchased for the Fund with those to be sold or
purchased for other accounts in order to obtain favorable execution and lower
brokerage commissions. In addition, Manager understands, and has advised Fund's
Board of Trustees, that the persons employed by Sub-Adviser to assist in
Sub-Adviser's duties under this Agreement will not devote their full such
efforts and service to the Fund. It is also agreed that the Sub-Adviser may use
any supplemental research obtained for the benefit of the Fund in providing
investment advice to its other investment advisory accounts or for managing its
own accounts.

      6. Limitation of Liability. Manager will not take any action against
Sub-Adviser to hold Sub-Adviser liable for any error of judgment or mistake of
law or for any loss suffered by the Fund in connection with the performance of
Sub-Adviser's duties under this Agreement, except for a loss resulting from
Sub-Adviser's willful misfeasance, bad faith, or gross negligence in the
performance of its duties or by reason of its reckless disregard of its
obligations and duties under this Agreement.

      7. Term; Termination; Amendment. This Agreement shall become effective
with respect to the Fund on the same date as the Management Agreement between
the Fund and the Manager becomes effective, provided that it has been approved
by a vote of a majority of the outstanding voting securities of the Fund in
accordance with the requirements of the 1940 Act, and shall remain in full force
until August 1, 2003 unless sooner terminated as hereinafter provided. This
Agreement shall continue in force from year to year thereafter with respect to
the Fund, but only as long as such continuance is specifically approved for the
Fund at least annually in the manner required by the 1940 Act and the rules and
regulations thereunder; provided, however, that if the continuation of this
Agreement is not approved for the Fund, the Sub-Adviser may continue to serve in
such capacity for the Fund in the manner and to the extent permitted by the 1940
Act and the rules and regulations thereunder.

      This Agreement shall automatically terminate in the event of its
assignment and may be terminated at any time without the payment of any penalty
by the Manager on sixty (60) days' written notice to the Sub-Adviser. This
Agreement may be terminated by the Sub-Adviser as of July 31 of any year after
2003 without payment of any penalty upon sixty (60) days' prior written notice
to the Manager. This Agreement may also be terminated by the Fund with respect
to the Fund by action of the Board of Trustees or by a vote of a majority of the
outstanding voting securities of such Fund on sixty (60) days' written notice to
the Sub-Adviser by the Fund.

      This Agreement may be terminated with respect to the Fund at any time
without the payment of any penalty by the Manager, the Board of Trustees or by
vote of a majority of the outstanding voting securities of the Fund in the event
that it shall have been established by a court of competent jurisdiction that
the Sub-Adviser or any officer or director of the Sub-Adviser has taken any
action which results in a breach of the covenants of the Sub-Adviser set forth
herein.

      The terms "assignment" and "vote of a majority of the outstanding voting
securities" shall have the meanings set forth in the 1940 Act and the rules and
regulations thereunder.

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      Termination of this Agreement shall not affect the right of the
Sub-Adviser to receive payments on any unpaid balance of the compensation
described in Section 4 earned prior to such termination. This Agreement shall
automatically terminate in the event the Investment Management Agreement between
the Manager and the Fund is terminated, assigned or not renewed.

      8. Notice. Any notice under this Agreement shall be in writing, addressed
and delivered or mailed, postage prepaid, to the other party

      If to the Manager:                    If to the Sub-Adviser:

      Nuveen Institutional Advisory Corp.   Security Capital Group Inc.
      333 West Wacker Drive                 11 South LaSalle Street
      Chicago, Illinois 60606               Chicago, Illinois  60603
      Attention:  John P. Amboian           Attention:  Anthony R. Manno, Jr.

      With a copy to:                       With a copy to:

      The John Nuveen Company               Security Capital Group, Inc.
      333 West Wacker Drive                 11 South LaSalle Street
      Chicago, Illinois 60606               Chicago, Illinois  60603
      Attention: General Counsel            Attention:  David T. Novick

or such address as such party may designate for the receipt of such notice.

      9. Limitations on Liability. All parties hereto are expressly put on
notice of the Fund's Agreement and Declaration of Trust and all amendments
thereto, a copy of which is on file with the Secretary of the Commonwealth of
Massachusetts, and the limitation of shareholder and trustee liability contained
therein. The obligations of the Fund entered in the name or on behalf thereof by
any of the Trustees, representatives or agents are made not individually but
only in such capacities and are not binding upon any of the Trustees, officers,
or shareholders of the Fund individually but are binding upon only the assets
and property of the Fund, and persons dealing with the Fund must look solely to
the assets of the Fund and those assets belonging to the subject Fund, for the
enforcement of any claims.

      10. Miscellaneous. The captions in this Agreement are included for
convenience of reference only and in no way define or delimit any of the
provisions hereof or otherwise affect their construction or effect. If any
provision of this Agreement is held or made invalid by a court decision,
statute, rule or otherwise, the remainder of this Agreement will not be affected
thereby. This Agreement will be binding upon and shall inure to the benefit of
the parties hereto and their respective successors.

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      11. Applicable Law. This Agreement shall be construed in accordance with
applicable federal law and (except as to Section 10 hereof which shall be
construed in accordance with the laws of Massachusetts) the laws of the State of
Illinois.

      IN WITNESS WHEREOF, the Manager and the Sub-Adviser have caused this
Agreement to be executed as of the day and year first above written.

NUVEEN INSTITUTIONAL ADVISORY CORP.,      SECURITY CAPITAL RESEARCH & MANAGEMENT
a Delaware corporation                    INCORPORATED, a Delaware corporation

By:  ____________________________         By:  ____________________________
Title: Vice President                     Title:  _________________________

                                       6<PAGE>
                                                                     Exhibit 4.3

                            CERTIFICATE OF ADJUSTMENT
                                       OF
                              eLOYALTY CORPORATION

To:         Mellon Investor Services LLC, as Rights Agent

            Each Transfer Agent for the Common Stock and Preferred Stock of
            eLoyalty Corporation

            eLOYALTY CORPORATION, a corporation organized and existing under the
laws of the State of Delaware (the "Company"), does hereby certify as follows:

            1. The Company is a party to the Rights Agreement, dated as of March
17, 2000, as amended (the "Agreement"), between the Company and Mellon Investor
Services LLC (formerly known as ChaseMellon Shareholder Services, L.L.C.), as
Rights Agent (the "Rights Agent").

            2. Effective as of 7:59 a.m., eastern standard time, on December 19,
2001 (the "Effective Time"), the Company effected a 1-for-10 reverse stock
split, whereby each ten shares of the common stock, par value $0.01 per share,
of the Company (the "Common Stock") issued as of immediately prior to the
Effective Time were reclassified into one share of new Common Stock, par value
$0.01 per share, of the Company, with fractional shares settled in cash (the
"Reclassification").

            3. Section 11 of the Agreement provides that in the event of any
combination of shares of Common Stock into a smaller number of shares, then, in
such case, the number of Rights (as defined in the Agreement) associated with
each share of Common Stock then outstanding, or issued or delivered thereafter
(but prior to the Distribution Date, as defined in the Agreement), shall be
proportionately adjusted so that the number of Rights thereafter associated with
each share of Common Stock following any such event shall equal the result
obtained by multiplying the number of Rights associated with each share of
Common Stock immediately prior to such event by a fraction the numerator of
which shall be the total number of shares of Common Stock outstanding
immediately prior to the occurrence of the event and the denominator of which
shall be the total number of shares of Common Stock outstanding immediately
following the occurrence of such event.

            4. Whenever an adjustment is made as provided in Section 11 of the
Agreement, the Company must, pursuant to Section 12 of the Agreement, among
other things, (a) prepare a certificate setting forth the adjustment and a brief
statement of the facts and computations accounting therefor and (b) file a copy
of such certificate with the Rights Agent and each transfer agent for the Common
Stock and the Company's Preferred Stock (as defined in the Agreement).

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            5. Pursuant to Section 12 of the Agreement, notification is hereby
given that the number of Rights associated with each share of Common Stock has
been adjusted from one (1) Right to ten (10) Rights.

            IN WITNESS WHEREOF, the undersigned has executed this Certificate of
Adjustment as of this 10th day of January, 2002.

                               eLOYALTY CORPORATION

                               By:       /s/ Timothy J. Cunningham
                                       -----------------------------
                               Name:   Timothy J. Cunningham
                               Title:  Senior Vice President and
                                       Chief Financial Officer

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