Filed Pursuant to Rule 424(b)(3)
                                                    Registration No. 333-107357
                                                             and No. 333-118965

                      S&P MANAGED FUTURES INDEX FUND, LP
                             ____________________

                                  SUPPLEMENT
                                      TO
                         PROSPECTUS DATED JULY 1, 2005
                             ____________________

               The date of this Supplement is October 20, 2005.

CURRENT STATUS OF FUND OPERATIONS
---------------------------------

On October 10, 2005, Refco, Inc., the ultimate parent of the general partner,
announced that it had discovered through an internal review a receivable owed
to Refco, Inc., by an entity controlled by Phillip R. Bennett, the then Chief
Executive Officer and Chairman of the Board of Directors of Refco, Inc., in
the amount of approximately $430 million.  Mr. Bennett has been charged with
securities fraud in connection with this matter and various actions have been
filed against Refco, Inc.  Thereafter, on October 13, 2005, Refco, Inc.,
announced that the liquidity within Refco Capital Markets, Ltd. ("RCM") was
no longer sufficient to continue operations and that RCM had imposed a
fifteen (15) day moratorium on all of its activities in an attempt to protect
the value of that enterprise.  On October 17, 2005, Refco, Inc. and RCM filed
for bankruptcy protection in the Southern District of New York.

Although the Fund's assets are not held directly with Refco, Inc., one of
Refco, Inc.'s affiliated entities, Refco, LLC, did indirectly serve as the
futures commission merchant through the Fund's investment in the SPhinX
Managed Futures Fund SPC (the "SPhinX Fund").  In addition, a portion of the
Fund's assets (less than 3%, based upon current market value) was indirectly
exposed to RCM through a number of foreign currency contracts held within the
portfolios of the SPhinX Fund.  The SPhinX Fund does not expect to be able to
unwind such foreign currency contracts with RCM until such time as the
bankruptcy proceedings reach a final resolution.

In light of the events outlined herein, the SPhinX Fund has moved all of its
assets from Refco, LLC, and has engaged Lehman Brothers and its affiliated
entities to act as futures commission merchant.  As of the close of business on
October 17, 2005, the SPhinX Fund no longer has assets on deposit with
Refco, LLC.  The SPhinX Fund plans to move the remaining assets held at RCM if
and when such assets become available.

The General Partner does not believe that these actions will have a material
impact upon the operations of the Fund or the SPhinX Fund, or, except as
described below, either's ability to satisfy a request for redemption.  In this
regard, the operations of the Fund and the SPhinX Fund, including the trading
activities of the underlying asset managers, have continued with minimal
interruption. Investors are cautioned, however, that there can be no assurances
(i) that the SPhinX Fund will have access to any or all of its assets in
accounts held at RCM, (ii) with respect to the amount or value of those assets,
when and if the SPhinX Fund obtains them, or (iii) the effect upon the SPhinX
Fund of future actions by RCM or others, any of which may ultimately impact the
SPhinX Fund's ability to value that portion of its assets held at RCM and/or
delay the payment of an investor's pro rata share of such assets upon
redemption.  In particular, the SPhinX Fund has informed the Fund that, with
respect to redemptions made as of October 14, 2005 or any date thereafter,
the SPhinX Fund intends to make payment in the ordinary course with respect
to not less than 95% of the proceeds of such redemptions, while reserving the
payment of not more than 5% of the proceeds until such time as it may
establish a reasonable valuation with respect to the foreign currency
contracts to which RCM is the counterparty.  As such, the Fund may reserve
payment with respect to not more than 5% of any redemption proceeds until
these monies are appropriately valued and remitted to the Fund by the SPhinX
Fund.  Once received by the Fund, it will promptly remit payment to redeeming
investors.

REFCO SECURITIES, LLC                                REFCOFUND HOLDINGS, LLC
    SELLING AGENT                                        GENERAL PARTNER



THE FOLLOWING UPDATES THE INFORMATION UNDER THE SUB-CAPTION "GENERAL PARTNER
- BACKGROUND AND MANAGEMENT" ON PAGE 26 OF THE PROSPECTUS DATED JULY 1, 2005.

    Mr. Philip R. Bennett is no longer a Manager of the general partner.

    Mr. Philip Silverman is no longer the Secretary of the general partner.  Mr.
Silverman was replaced as Chief Financial Officer of the general partner
effective August 2005 by Mr. Keith D. Kemp.

    Mr. Richard C. Butt, President of the general partner, was appointed a
Manager of the general partner.  Mr. Butt, together with Ms. Cazenave, will
serve as the audit committee of the Managers of the General Partner.

    Ms. Annette A. Cazenave, age 49, was appointed a Manager of the general
partner, pending her registration as a principal of the general partner with
the National Futures Association.  Ms. Cazenave, together with Mr. Butt, will
serve as the audit committee of the Managers of the General Partner.  Ms.
Cazenave joined Refco Commodities Management, Inc. on September 1, 2005 in
connection with its acquisition of the global brokerage operations of Cargill
Investor Services, Inc.  She joined Cargill Investor Services, Inc. in March
2004 with over twenty-four years of comprehensive experience in alternative
asset management (futures, derivatives and hedge funds) marketing and
business management.  Previously, Ms. Cazenave was VP, Marketing and Product
Development, for Horizon Cash Management, LLC (January 2002- March 2004).
Prior to this, she was President and Principal of Skylark Partners, Inc.
(March 1993 - December 2001) in New York, a financial services consulting
firm. During this time, Ms. Cazenave acted as a consultant on behalf of
Liberty Funds Group among others. Additionally, Ms. Cazenave held senior
level positions with ED&F Man Funds Division (now Man Investments) in New
York (March 1986-March 1993).  Ms. Cazenave began her career in August 1979
as a Sugar trader and holds a B.A. from Drew University and an M.B.A. from
Thunderbird, The American Graduate School of International Management.

    Mr. Keith D. Kemp, age 44, is Chief Financial Officer and Secretary of the
general partner.  Mr. Kemp has been Vice President of Operations for Refco
Alternative Investments LLC since October 2003, where he is responsible for
onshore and offshore product operations.  Mr. Kemp has also been the Chief
Financial Officer/Accounting Officer for Refco Commodities Management Inc.
since September 1, 2005.  Prior to joining Refco, Mr. Kemp worked as an
independent consultant from March 2003 to October 2003.  Mr. Kemp spent April
2002 to February 2003 traveling.  From July 2000 to March 2002, Mr. Kemp was
Senior Vice President and Chief Operating Officer of Orbitex Fund Services,
Inc., where he was responsible for fund accounting, fund administration and
transfer agency.  From February 1999 to July 2000, Mr. Kemp was Vice
President at Orbitex Management, Inc., where he was responsible for onshore
and offshore product operations.  Mr. Kemp holds a B.S. in Accounting from
the State University of New York.
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