[LETTERHEAD OF SULLIVAN & WORCESTER LLP]

                                                    Boston
                                                    January 29, 2001

The Trustees of
  Mercury HW Variable Trust
725 South Figueroa St., Suite 4000
Los Angeles, California 90017-5400

Ladies and Gentlemen:

      You have requested our opinion, as your special Massachusetts  counsel, as
to certain matters of  Massachusetts  law relating (i) to the  organization  and
shares of Mercury HW Variable  Trust,  a trust with  transferable  shares  under
Massachusetts law (the "Trust"),  and (ii) to the shares of beneficial interest,
without par value, of the Trust's Mercury HW International Value VIP Series (the
"VIP  Series",  and such  shares  of  beneficial  interest,  the  "Shares").  We
understand  that our opinion is requested in  connection  with the filing by the
Trust with the Securities and Exchange  Commission (the "SEC") of a Registration
Statement  on Form N-14  under  the  Securities  Act of 1933,  as  amended  (the
"Securities   Act",  and  such   Registration   Statement,   the   "Registration
Statement"),  relating to the Shares (the "Subject  Shares") to be issued by the
VIP Series pursuant to an Agreement and Plan of Reorganization (the "Agreement")
between the Trust and Merrill  Lynch  Variable  Series  Funds,  Inc., a Maryland
corporation  ("Variable Series Fund"),  under which the VIP Series is to acquire
substantially  all the assets,  subject to  liabilities,  of the  Merrill  Lynch
International  Equity  Focus  Fund  ("Focus  Fund"),  one of the  portfolios  of
Variable Series Fund (collectively, the "Reorganization"),  and that you wish to
file this letter with the SEC as an exhibit to the Registration Statement.

      The  Trust  was  established  pursuant  to a  Declaration  of Trust  dated
February 4, 1997 (the  "Original  Declaration"),  as amended by a Certificate of
Amendment dated September 15, 2000, and  supplemented by an Amended  Certificate
of Designation  dated October 10, 1997 and Amended and Restated  Certificates of
Designation  dated  September  15, 2000 and January 5, 2001  (collectively,  the
"Certificate of Designation",  and the Original  Declaration,  as so amended and
supplemented, the "Declaration").  For purposes of rendering the opinions stated
herein, we have examined and are familiar with the Declaration and the Bylaws of
the  Trust,  as  currently  in  effect,  and we have  reviewed:  a proof  of the
Agreement which we are informed is  substantially  in the form to be filed as an
exhibit to the Registration  Statement;  a proof of the  Registration  Statement
which we are  informed  is  substantially  in the form to be filed with the SEC,
including the form of the Proxy  Statement/Prospectus (the "Prospectus") forming
part thereof,  relating to the Reorganization and the Subject Shares; records of
the actions  taken by  yourselves  to authorize the issuance and delivery of the
Subject  Shares to Focus  Fund;  certificates  of  officers  of the Trust and of
public officials as to matters of fact relevant to such opinions; and such other
documents   and   instruments,   certified  or  otherwise   identified   to  our
satisfaction, and such questions of law



The Trustees of
   Mercury HW Variable Trust          -2-                       January 29, 2001

and fact, as we have considered  necessary or appropriate for purposes of giving
such opinions.  We call to your attention that, in doing so, we have assumed the
genuineness  of the  signatures  on,  and the  authenticity  of,  all  documents
furnished to us, and the  conformity to the originals of documents  submitted to
us as copies, which we have not independently verified.

      Based upon and subject to the foregoing, we hereby advise you that, in our
opinion, under the laws of Massachusetts:

      1.    The Trust is validly existing as a trust with transferable shares of
            the type commonly called a Massachusetts business trust.

      2.    The VIP Series has been duly established as a separate  portfolio of
            the assets of the Trust pursuant to the Certificate of Designation.

      3.    The  Subject  Shares have been duly and  validly  authorized  by all
            requisite  action of the Trustees of the Trust, and no action by the
            shareholders  of the Trust or of the VIP Series is  required in such
            connection.

      4.    The  Subject  Shares,  when duly  issued and  delivered  to Variable
            Series  Fund,  acting on behalf of Focus Fund,  in exchange  for the
            assets, subject to liabilities,  of Focus Fund, and their subsequent
            delivery to the  shareholders  of Focus Fund, all as contemplated by
            the Agreement,  will be validly and legally  issued,  fully paid and
            nonassessable by the Trust or by the VIP Series.

      With respect to the opinion  expressed  in  paragraph 4 above,  we wish to
point out that the shareholders of a Massachusetts business trust may under some
circumstances  be subject to  assessment at the instance of creditors to pay the
obligations of such trust in the event that its assets are  insufficient for the
purpose.

      This letter expresses our opinions as to the provisions of the Declaration
and the laws of Massachusetts  applying to business trusts  generally,  but does
not extend to the  Massachusetts  Securities  Act, or to federal  securities  or
other laws.

      We consent to your  filing  this  letter with the SEC as an exhibit to the
Registration  Statement,  but we do not thereby  concede that we come within the
category of persons whose consent is required  under Section 7 of the Securities
Act.

                                             Very truly yours,



                                             /s/ SULLIVAN & WORCESTER LLP