Exhibit 99.1350CERT

         Certification Pursuant to Section 906 of the Sarbanes Oxley Act

      I, Terry K. Glenn, President of Merrill Lynch Large Cap Growth Fund (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: June 23, 2003


                                             /s/ Terry K. Glenn
                                             ------------------
                                             Terry K. Glenn,
                                             President of
                                             Merrill Lynch Large Cap Growth Fund

      A signed original of this written statement required by Section 906 has
      been provided to Merrill Lynch Large Cap Growth Fund and will be retained
      by Merrill Lynch Large Cap Growth Fund and furnished to the Securities and
      Exchange Commission or 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 Large Cap
      Growth Fund (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: June 23, 2003


                                             /s/ Donald C. Burke
                                             -------------------
                                             Donald C. Burke,
                                             Chief Financial Officer of
                                             Merrill Lynch Large Cap Growth Fund

      A signed original of this written statement required by Section 906 has
      been provided to Merrill Lynch Large Cap Growth Fund and will be retained
      by Merrill Lynch Large Cap Growth Fund and furnished to the Securities and
      Exchange Commission or staff upon request.