Smith Barney Futures Management LLC
                         388 Greenwich Street, 7th Floor
                          New York, New York 10013-2396



June 22, 1998



Campbell & Co. Inc.
210 West Pennsylvania Avenue
Baltimore, MD 212104

Attn: Ms. Terry Livesey

         Re:      Management Agreement Renewal
                  Smith Barney Potomac Futures  Fund L.P.


Dear Ms. Livesey:

We are  writing  with  respect  to  your  management  agreement  concerning  the
commodity pool to which reference is made above (the "Management Agreement"). We
would like to extend the term of the Management  Agreement through June 30, 1999
and make the  atthaced  modification  on Rider 1. All  other  provisions  of the
Management Agreement will remain unchanged.

Please indicate your agreement to and acceptance of this modification by signing
one copy of this letter and returning it to the attention of Mr. Daniel Dantuono
at the address above or fax to 212-723-8985.  If you have any questions I can be
reached at 212-723-5416.



Very truly yours,

SMITH BARNEY FUTURES MANAGEMENT LLC


By: /s/  Daniel A. Dantuono
         Daniel A. Dantuono
         Chief Financial Officer,
         Director & Treasurer

AGREED AND ACCEPTED
CAMPBELL & CO. INC.


By:    /s/   Theresa D.  Livesey

Print Name:  Theresa D. Livesey
             Chief Financial Officer
             Campbell & Co. Inc.



                                    RIDER I


     (1) The  Advisor  further  agrees  that it will  instruct  Smith  Barney to
convert foreign currency balances (nor required to margin positions  denominated
in a  foreign  currency)  to U.S.  dollars  no  less  frequently  than  monthly.
Instruction  will  take the form of a fax  transmitted  monthly  specifying  the
account name and number using the following language:

          "Please  convert  all foreign  currency  balances  for the  account(s)
     specified above that are not required to margin position denominated in the
     foreign currency to U.S. dollars."

     (2) The Advisor's  performance  tables have been examined by an independent
certified  public  accountant  and the report thereon has been provided to SBFM.
The Advisor will have its  performance  tables  examined no less frequently than
annually during the term of this Agreement.

     (3) The Advisor may terminate the Management Agreement at any time, upon 30
days prior notice to SBFM.