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                            SECTION 906 CERTIFICATION

                Certification Pursuant to 18 U.S.C. Section 1350,
                             As Adopted Pursuant to
                  Section 906 of the Sarbanes-Oxley Act of 2002

Morgan Stanley Morgan Stanley S&P 500 Index Fund


     In connection with the Report on Form N-CSR (the "Report") of the
above-named issuer for the period ended February 29, 2004 that is accompanied by
this certification, the undersigned hereby certifies that:

1.   The Report fully complies with the requirements of Section 13(a) or 15(d)
     of the Securities Exchange Act of 1934; and

2.   The information contained in the Report fairly presents, in all material
     respects, the financial condition and results of operations of the Issuer.

Date: April 20, 2004                  /s/ Ronald E. Robison
                                          --------------------
                                          Ronald E. Robison
                                          Principal Executive Officer

A signed original of this written statement required by Section 906 has been
provided to Morgan Stanley S&P 500 Index Fund and will be retained by Morgan
Stanley S&P 500 Index Fund and furnished to the Securities and Exchange
Commission or its staff upon request.

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                            SECTION 906 CERTIFICATION

                Certification Pursuant to 18 U.S.C. Section 1350,
                             As Adopted Pursuant to
                  Section 906 of the Sarbanes-Oxley Act of 2002

Morgan Stanley Morgan Stanley S&P 500 Index Fund


     In connection with the Report on Form N-CSR (the "Report") of the
above-named issuer for the period ended February 29, 2004 that is accompanied by
this certification, the undersigned hereby certifies that:

1.   The Report fully complies with the requirements of Section 13(a) or 15(d)
     of the Securities Exchange Act of 1934; and

2.   The information contained in the Report fairly presents, in all material
     respects, the financial condition and results of operations of the Issuer.

Date: April 20, 2004                  /s/  Francis Smith
                                           ------------------
                                           Francis Smith
                                           Principal Financial Officer

A signed original of this written statement required by Section 906 has been
provided to Morgan Stanley S&P 500 Index Fund and will be retained by Morgan
Stanley S&P 500 Index Fund and furnished to the Securities and Exchange
Commission or its staff upon request.