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                                                                    Exhibit 4(l)

                             SUB-ADVISORY AGREEMENT

     Agreement made as of September 16, 2002 between UBS GLOBAL ASSET MANAGEMENT
(US) INC. ("UBS Global AM"), a Delaware corporation, and MARSICO CAPITAL
MANAGEMENT, LLC ("Sub-Adviser"), a Delaware limited liability corporation (the
"Agreement").

                                    RECITALS

     (1)  UBS Global AM has entered into a Management Agreement dated June 15,
1995 ("Management Agreement") with UBS PACE Select Advisors Trust (formerly
known as Managed Accounts Services Portfolio Trust ("Trust")), an open-end
management investment company registered under the Investment Company Act of
1940, as amended ("1940 Act"), with respect to UBS PACE LARGE CO GROWTH EQUITY
INVESTMENTS ("Portfolio");

     (2)  UBS Global AM desires to retain the Sub-Adviser to furnish certain
investment advisory services to UBS Global AM and the Portfolio; and

     (3)  The Sub-Adviser is willing to furnish such services;

     NOW, THEREFORE, in consideration of the premises and mutual covenants
herein contained, UBS Global AM and the Sub-Adviser agree as follows:

     1.   APPOINTMENT. UBS Global AM hereby appoints the Sub-Adviser as an
investment sub-adviser with respect to the Portfolio for the period and on the
terms set forth in this Agreement. The Sub-Adviser accepts that appointment and
agrees to render the services herein set forth, for the compensation herein
provided.

     2.   DUTIES AS SUB-ADVISER.

     (a)  Subject to the supervision and direction of the Trust's Board of
Trustees (the "Board") and review by UBS Global AM, and any written guidelines
adopted by the Board or UBS Global AM, the Sub-Adviser will provide a continuous
investment program for all or a designated portion of the assets ("Segment") of
the Portfolio, including investment research and discretionary management with
respect to all securities and investments and cash equivalents in the Portfolio
or Segment. The Sub-Adviser will determine from time to time what investments
will be purchased, retained or sold by the Portfolio or Segment. The Sub-Adviser
will be responsible for placing purchase and sell orders for investments and for
other related transactions for the Portfolio or Segment. The Sub-Adviser will be
responsible for voting proxies of issuers of securities held by the Portfolio or
Segment. The Sub-Adviser understands that the Portfolio's assets need to be
managed so as to permit the Portfolio to qualify or to continue to qualify as a
regulated investment company under Subchapter M of the Internal Revenue Code, as
amended ("Code"). The Sub-Adviser will provide services under this Agreement in
accordance with the Portfolio's investment objective, policies and restrictions
as stated in the Trust's currently effective registration statement under the
1940 Act, and any amendments or supplements thereto ("Registration Statement").

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     (b)  The Sub-Adviser agrees that, in placing orders with brokers selected
at the discretion of the Sub-Adviser, it will seek the best net result in terms
of price and execution; provided that, on behalf of the Portfolio, the
Sub-Adviser may, in its discretion, use brokers that provide the Sub-Adviser
with research, analysis, advice and similar services to execute portfolio
transactions on behalf of the Portfolio, and the Sub-Adviser may pay to those
brokers in return for brokerage and research services a higher commission than
may be charged by other brokers, subject to the Sub-Adviser's determination in
good faith that such commission is reasonable in terms either of the particular
transaction or of the overall responsibility of the Sub-Adviser to the Portfolio
and its other clients and that the total commissions will be reasonable in
relation to the value of research and brokerage services provided by the brokers
to the Sub-Adviser and its clients. In no instance will portfolio securities be
purchased from or sold to UBS Global AM or the Sub-Adviser, or any affiliated
person thereof, except in accordance with the federal securities laws and the
rules and regulations thereunder. The Sub-Adviser may aggregate sales and
purchase orders with respect to the assets of the Portfolio or Segment with
similar orders being made simultaneously for other accounts advised by the
Sub-Adviser or its affiliates. Whenever the Sub-Adviser simultaneously places
orders to purchase or sell the same security on behalf of the Portfolio and one
or more other accounts advised by the Sub-Adviser, the orders will be allocated
as to price and amount among all such accounts in a manner believed to be
equitable over time to each account. UBS Global AM recognizes that in some cases
this procedure may adversely affect the results obtained for the Portfolio or
Segment.

     Subject to the Sub-Adviser's obligations to seek best execution, UBS Global
AM agrees that the Sub-Adviser, in its sole discretion, may place transactions
on behalf of the Portfolio and the Trust with any broker-dealer deemed to be an
affiliate of the Sub-Adviser (the "Affiliated Broker-Dealers") so long as such
transactions are effected in conformity with applicable law, including Rule
17e-1 under the Investment Company Act. UBS Global AM hereby consents to the
Sub-Adviser's use of an affiliated broker to effect transactions for the
Portfolio and the Trust on an exchange under Section 11(a)(1)(H) of the
Securities Exchange Act of 1934 (including any applicable exemptions and
administrative interpretations set forth in Part II of the Sub-Adviser's Form
ADV Registration Statement on file with the Securities and Exchange Commission
("Form ADV")). In all such dealings, the Affiliated Broker-Dealers shall be
authorized and entitled to retain any commissions, remuneration or profits which
may be made in such transactions and shall not be liable to account for the same
to UBS Global AM, the Series or the Trust. UBS Global AM is aware that the
affiliation between the Sub-Adviser and an Affiliated Broker-Dealer could give
the Sub-Adviser an indirect interest in brokerage commissions received by the
Affiliated Broker-Dealer, creating a potential conflict of interest.

     UBS Global AM further authorizes the Sub-Adviser and its Affiliated
Broker-Dealers to execute agency cross transactions (the "Cross Transactions")
on behalf of the Portfolio and the Trust. Cross Transactions are transactions
which may be effected by the Affiliated Broker-Dealers acting for both the
Portfolio or the Trust and the counterparty to the transaction. Cross
Transactions enable the Sub-Adviser to purchase or sell a block of securities
for the Portfolio or the Trust at a set price and possibly avoid an unfavorable
price movement that may be created through entrance into the market with such
purchase or sale order. As such, the Sub-Adviser believes that Cross
Transactions can provide meaningful benefits for the Portfolio and the Trust and
its clients generally. UBS Global AM, the Portfolio and the Trust should be
aware, however,

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that in a Cross Transaction an Affiliated Broker-Dealer will be receiving
commissions from both sides of the trade and, therefore, there is a potentially
conflicting division of loyalties and responsibilities.

     (c)  The Sub-Adviser will maintain all books and records required to be
maintained pursuant to Rule 31a-1(b)(2)(ii), (3), (5), (6), (7), (9) and (10)
under the 1940 Act and the rules and regulations promulgated thereunder with
respect to transactions by the Sub-Adviser on behalf of the Portfolio or
Segment, and will furnish the Board and UBS Global AM with such periodic and
special reports as the Board or UBS Global AM reasonably may request. In
compliance with the requirements of Rule 31a-3 under the 1940 Act, the
Sub-Adviser hereby agrees that all records which it maintains for the Portfolio
are the property of the Trust, agrees to preserve for the periods prescribed by
Rule 31a-2 under the 1940 Act any records that it maintains for the Portfolio
and that are required to be maintained by Rule 31a-1 under the 1940 Act, and
further agrees to surrender promptly to the Trust any records which it maintains
for the Portfolio upon request by the Trust (provided that the Sub-Adviser may
retain copies of all records for its own records).

     (d)  At such times as shall be reasonably requested by the Board or UBS
Global AM, the Sub-Adviser will provide the Board and UBS Global AM with
economic and investment analyses and reports as well as quarterly reports
setting forth the performance of the Portfolio or Segment and make available to
the Board and UBS Global AM any economic, statistical and investment services
that the Sub-Adviser normally makes available to its institutional or other
customers.

     (e)  In accordance with procedures adopted by the Board, as amended from
time to time, the Sub-Adviser is responsible for assisting in the fair valuation
of all portfolio securities in the Portfolio or Segment and will use its
reasonable efforts to arrange for the provision of a price or prices from one or
more parties independent of the Sub-Adviser for each portfolio security for
which the custodian does not obtain prices in the ordinary course of business
from an automated pricing service.

     3.   FURTHER DUTIES. In all matters relating to the performance of this
Agreement, the Sub-Adviser will seek to act in conformity with the Trust's Trust
Instrument, By-Laws and Registration Statement and with the written instructions
and written directions of the Board and UBS Global AM; and will comply with the
requirements of the 1940 Act, and the Investment Advisers Act of 1940, as
amended ("Advisers Act"), and the rules under each, the Code, and all other
federal and state laws and regulations applicable to the Trust and the
Portfolio. UBS Global AM agrees to provide to the Sub-Adviser copies of the
Trust's Trust Instrument, By-Laws, Registration Statement, written instructions
and directions of the Board and UBS Global AM, and any amendments or supplements
to any of these materials as soon as practicable after such materials become
available; and further agrees to identify to the Sub-Adviser in writing any
broker-dealers that are affiliated with UBS Global AM (other than UBS
PaineWebber Incorporated and UBS Global AM itself).

     4.   EXPENSES. During the term of this Agreement, the Sub-Adviser will bear
all expenses incurred by it in connection with its services under this
Agreement. The Sub-Adviser shall not be responsible for any expenses incurred by
the Trust, the Portfolio or UBS Global AM, such as, without limitation, the
costs of executing any transaction for the Trust or the Portfolio.

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     5.   COMPENSATION.

     (a)  For the services provided and the expenses assumed by the Sub-Adviser
pursuant to this Agreement, UBS Global AM, not the Portfolio, will pay to the
Sub-Adviser a fee, computed daily and payable monthly, at an annual rate of
0.30% of the average daily net assets of the Portfolio or Segment allocated to
its management (computed in the manner specified in the Management Agreement),
and will provide the Sub-Adviser with a schedule showing the manner in which the
fee was computed. If the Sub-Adviser is managing a Segment, its fees will be
based on the value of the assets of the Portfolio within the Sub-Adviser's
Segment. No statement in this Agreement or any document constitutes a
representation by the Sub-Adviser regarding the rate of growth or return of the
Portfolio or Segment. Neither the Sub-Adviser nor any of its officers, directors
or employees make any representations or warranties, express or implied, that
any level of performance or investment results will be achieved by the Portfolio
or Segment, or that it will perform comparably with any standard or index,
including the performance of other clients of Sub-Adviser.

     (b)  The fee shall be accrued daily and payable monthly to the Sub-Adviser
on or before the last business day of the next succeeding calendar month.

     (c)  If this Agreement becomes effective or terminates before the end of
any month, the fee for the period from the effective date to the end of the
month or from the beginning of such month to the date of termination, as the
case may be, shall be pro-rated according to the proportion which such period
bears to the full month in that such effectiveness or termination occurs.

     6.   LIMITATION OF LIABILITY.

     (a)  The Sub-Adviser shall not be liable for any error of judgment or
mistake of law or for any loss suffered by the Portfolio, the Trust or its
shareholders or by UBS Global AM in connection with the matters to which this
Agreement relates, except a loss resulting from willful misfeasance, bad faith
or gross negligence on its part in the performance of its duties or from
reckless disregard by it of its obligations and duties under this Agreement.

     (b)  In no event will the Sub-Adviser have any responsibility for any other
series of the Trust, for any portion of the Portfolio not managed by the
Sub-Adviser or for the acts or omissions of any other sub-adviser to the Trust
or Portfolio.

     In particular, in the event the Sub-Adviser shall manage only a portion of
the Portfolio's investments, the Sub-Adviser shall have no responsibility for
the Portfolio's being in violation of any applicable law or regulation or
investment policy or restriction applicable to the Portfolio as a whole or for
the Portfolio's failing to qualify as a regulated investment company under the
Code, if the securities and other holdings of the Segment of the Portfolio
managed by the Sub-Adviser are such that such Segment would not be in such
violation or fail to so qualify if such Segment were deemed a separate series of
the Trust or a separate "regulated investment company" under the Code.

     Nothing in this section shall be deemed a limitation or waiver of any
obligation or duty that may not by law be limited or waived.

     7.   REPRESENTATIONS OF SUB-ADVISER AND/OR UBS GLOBAL AM. The Sub-Adviser
or, where applicable, UBS GLOBAL AM, represents, warrants and agrees as follows:

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     (a)  The Sub-Adviser (i) is registered as an investment adviser under the
Advisers Act and will continue to be so registered for so long as this Agreement
remains in effect; (ii) is not prohibited by the 1940 Act or the Advisers Act
from performing the services contemplated by this Agreement; (iii) has met, and
will seek to continue to meet for so long as this Agreement remains in effect,
any other applicable federal or state requirements, or the applicable
requirements of any regulatory or industry self-regulatory agency, necessary to
be met in order to perform the services contemplated by this Agreement; (iv) has
the authority to enter into and perform the services contemplated by this
Agreement; and (v) will promptly notify UBS Global AM of the occurrence of any
event that would disqualify the Sub-Adviser from serving as an investment
adviser of an investment company pursuant to Section 9(a) of the 1940 Act or
otherwise.

     (b)  The Sub-Adviser has adopted a written code of ethics complying with
the requirements of Rule 17j-1 under the 1940 Act and will provide UBS Global AM
and the Board with a copy of such code of ethics, together with evidence of its
adoption. Within a reasonable time after the end of the last calendar quarter of
each year that this Agreement is in effect, a duly authorized officer of the
Sub-Adviser shall certify to UBS Global AM that the Sub-Adviser has complied
with the requirements of Rule 17j-1 during the previous year and that there has
been no material violation of the Sub-Adviser's code of ethics or, if such a
violation has occurred, that appropriate action was taken in response to such
violation. Upon the written request of UBS Global AM, the Sub-Adviser shall
permit UBS Global AM, its employees or its agents to examine the reports
required to be made pursuant to Rule 17j-1 and all other records relevant to the
Sub-Adviser's code of ethics.

     (c)  The Sub-Adviser has provided UBS Global AM with a copy of its Form
ADV, as most recently filed with the Securities and Exchange Commission ("SEC"),
and promptly will furnish a copy of all amendments to UBS Global AM at least
annually.

     (d)  The Sub-Adviser will notify UBS Global AM of any change of control of
the Sub-Adviser, including any change of its general partners or 25%
shareholders or 25% limited partners, as applicable, and any changes in the key
personnel who are either the portfolio manager(s) of the Portfolio or senior
management of the Sub-Adviser, in each case prior to or promptly after such
change.

     (e)  UBS Global AM represents that it has received a copy of the
Sub-Adviser's Form ADV. UBS Global AM and the Sub-Adviser agree that neither of
them nor any of their affiliates, will in any way refer directly or indirectly
to their relationship with one another or any of their respective affiliates in
offering, marketing or other promotional materials without the express written
consent of the other, which consent will be promptly provided and not
unreasonably withheld. UBS Global AM consents to the Sub-Adviser's listing of
UBS Global AM and the Trust and Portfolio in standard client lists disclosed by
the Sub-Adviser.

     8.   SERVICES NOT EXCLUSIVE. The services furnished by the Sub-Adviser
hereunder are not to be deemed exclusive, and except as the Sub-Adviser may
otherwise agree in writing, the Sub-Adviser shall be free to furnish similar
services to others so long as its services under this Agreement are not impaired
thereby. Nothing in this Agreement shall limit or restrict the right of any
director, officer or employee of the Sub-Adviser, who may also be a trustee,
officer or employee of the Trust, to engage in any other business or to devote
his or her time and attention in

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part to the management or other aspects of any other business, whether of a
similar nature or a dissimilar nature. The Sub-Adviser may provide investment
advice to other clients that may differ from its advice to the Portfolio or
Segment. The Sub-Adviser, its clients, or its affiliates may engage in
transactions that differ from or conflict with the transactions undertaken on
behalf of the Portfolio or Segment, subject to any restrictions under applicable
law or this Agreement.

     9.   DURATION AND TERMINATION.

     (a)  This Agreement shall become effective upon the date first above
written, provided that this Agreement shall not take effect unless it has first
been approved (i) by a vote of a majority of those trustees of the Trust who are
not parties to this Agreement or interested persons of any such party
("Independent Trustees"), cast in person at a meeting called for the purpose of
voting on such approval, and (ii) by vote of a majority of the Portfolio's
outstanding voting securities, unless UBS Global AM has authority to enter into
this Agreement pursuant to exemptive relief from the SEC without a vote of the
Portfolio's outstanding voting securities.

     (b)  Unless sooner terminated as provided herein, this Agreement shall
continue in effect for two years from its effective date. Thereafter, if not
terminated, this Agreement shall continue automatically for successive periods
of twelve months each, provided that such continuance is specifically approved
at least annually (i) by a vote of a majority of the Independent Trustees, cast
in person at a meeting called for the purpose of voting on such approval, and
(ii) by the Board or by vote of a majority of the outstanding voting securities
of the Portfolio.

     (c)  Notwithstanding the foregoing, this Agreement may be terminated at any
time, without the payment of any penalty, by vote of the Board or by a vote of a
majority of the outstanding voting securities of the Portfolio on 60 days'
written notice to the Sub-Adviser. This Agreement may also be terminated,
without the payment of any penalty, by UBS Global AM: (i) upon 120 days' written
notice to the Sub-Adviser; (ii) upon material breach by the Sub-Adviser of any
of the representations, warranties and agreements set forth in Paragraph 7 of
this Agreement; or (iii) immediately if, in the reasonable judgment of UBS
Global AM, the Sub-Adviser becomes unable to discharge its duties and
obligations under this Agreement, including circumstances such as financial
insolvency of the Sub-Adviser or other circumstances that could adversely affect
the Portfolio. The Sub-Adviser may terminate this Agreement at any time, without
the payment of any penalty, on 120 days' written notice to UBS Global AM. This
Agreement will terminate automatically in the event of its assignment or upon
termination of the Management Agreement, as it relates to this Portfolio.

     10.  AMENDMENT OF THIS AGREEMENT. No provision of this Agreement may be
changed, waived, discharged or terminated orally, but only by an instrument in
writing signed by the party against whom enforcement of the change, waiver,
discharge or termination is sought. To the extent required by applicable law, no
amendment of this Agreement shall be effective until approved (i) by a vote of a
majority of the Independent Trustees, and (ii) if the terms of this Agreement
shall have changed, by a vote of a majority of the Portfolio's outstanding
voting securities (except in the case of (ii), pursuant to the terms and
conditions of the SEC order permitting it to modify the Agreement without such
vote).

     11.  GOVERNING LAW. This Agreement shall be construed in accordance with
the 1940

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Act and the laws of the State of New York, without giving effect to the
conflicts of laws principles thereof. To the extent that the applicable laws of
the State of New York conflict with the applicable provisions of the 1940 Act,
the latter shall control.

     12.  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 shall be held or made invalid by a court decision,
statute, rule or otherwise, the remainder of this Agreement shall not be
affected thereby. This Agreement shall be binding upon and shall inure to the
benefit of the parties hereto and their respective successors. As used in this
Agreement, the terms "majority of the outstanding voting securities,"
"affiliated person," "interested person," "assignment," "broker," "investment
adviser," "net assets," "sale," "sell" and "security" shall have the same
meanings as such terms have in the 1940 Act, subject to such exemption as may be
granted by the SEC by any rule, regulation or order. Where the effect of a
requirement of the federal securities laws reflected in any provision of this
Agreement is made less restrictive by a rule, regulation or order of the SEC,
whether of special or general application, such provision shall be deemed to
incorporate the effect of such rule, regulation or order. This Agreement may be
signed in counterpart.

     13.  NOTICES. Any notice herein required is to be in writing and is deemed
to have been given to the Sub-Adviser or UBS Global AM upon receipt of the same
at their respective addresses set forth below. All written notices required or
permitted to be given under this Agreement will be delivered by personal
service, by postage mail return receipt requested or by facsimile machine or a
similar means of same delivery which provides evidence of receipt (with a
confirming copy by mail as set forth herein). All notices provided to UBS Global
AM will be sent to the attention of Amy Doberman, General Counsel. All notices
provided to the Sub-Adviser will be sent to the attention of Mary Watson, Chief
Operations Officer.

     IN WITNESS WHEREOF, the parties hereto have caused this instrument to be
executed by their duly authorized signatories as of the date and year first
above written.

                                       UBS GLOBAL ASSET
                                       MANAGEMENT (US) INC.
                                       51 West 52nd Street
Attest:                                New York, New York 10019-6114

By:    Todd Lebo                       By:   /s/ Amy R. Doberman
       ---------------------------           ---------------------------
       Name:  Todd Lebo                      Name:  Amy R. Doberman
       Title: Director                       Title: Managing Director


                                       MARSICO CAPITAL MANAGEMENT, LLC


Attest:

By:    /s/ Tom Kerwin                  By:   /s/ Chris Marsico
       ---------------------------           ---------------------------
       Name:  Tom Kerwin                     Name:  Chris Marsico
       Title: VP & General Counsel           Title: President



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