Exhibit 99.1350CERT

         Certification Pursuant to Section 906 of the Sarbanes Oxley Act

I, Terry K. Glenn, President of Merrill Lynch Low Duration Fund of Merrill Lynch
Investment Managers Funds, Inc. and Low Duration Master Portfolio of Fund Asset
Management Master Trust (together, the "Fund"), certify that:

      1.    The N-CSR of the Fund (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 Fund.

Dated: August 13, 2004

                                             /s/ Terry K. Glenn
                                             -----------------------------------
                                             Terry K. Glenn,
                                             President of
                                             Merrill Lynch Low Duration Fund of
                                             Merrill Lynch Investment Managers
                                             Funds, Inc. and Low Duration Master
                                             Portfolio of Fund Asset Management
                                             Master Trust

A signed original of this written statement required by Section 906, or other
document authenticating, acknowledging, or otherwise adopting the signature that
appears in typed form within the electronic version of this written statement
required by Section 906, has been provided to Merrill Lynch Low Duration Fund of
Merrill Lynch Investment Managers Funds, Inc. and Low Duration Master Portfolio
of Fund Asset Management Master Trust and will be retained by Merrill Lynch Low
Duration Fund of Merrill Lynch Investment Managers Funds, Inc. and Low Duration
Master Portfolio of Fund Asset Management Master Trust and furnished to the
Securities and Exchange Commission or its staff upon request.



Exhibit 99.1350CERT

         Certification Pursuant to Section 906 of the Sarbanes Oxley Act

I, Donald C. Burke, Chief Financial Officer of Merrill Lynch Low Duration Fund
of Merrill Lynch Investment Managers Funds, Inc. and Low Duration Master
Portfolio of Fund Asset Management Master Trust (together, the "Fund"), certify
that:

      1.    The N-CSR of the Fund (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 Fund.

Dated: August 13, 2004

                                             /s/ Donald C. Burke
                                             -----------------------------------
                                             Donald C. Burke,
                                             Chief Financial Officer of
                                             Merrill Lynch Low Duration Fund of
                                             Merrill Lynch Investment Managers
                                             Funds, Inc. and Low Duration Master
                                             Portfolio of Fund Asset Management
                                             Master Trust

A signed original of this written statement required by Section 906, or other
document authenticating, acknowledging, or otherwise adopting the signature that
appears in typed form within the electronic version of this written statement
required by Section 906, has been provided to Merrill Lynch Low Duration Fund of
Merrill Lynch Investment Managers Funds, Inc. and Low Duration Master Portfolio
of Fund Asset Management Master Trust and will be retained by Merrill Lynch Low
Duration Fund of Merrill Lynch Investment Managers Funds, Inc. and Low Duration
Master Portfolio of Fund Asset Management Master Trust and furnished to the
Securities and Exchange Commission or its staff upon request.