<DOCUMENT>
<TYPE>EX-99.D.4
<SEQUENCE>4
<FILENAME>y42087a2ex99-d_4.txt
<DESCRIPTION>FORM OF DTC PARTICIPATION OVERSUBSCRIPTION FORM
<TEXT>

<PAGE>   1

                                                                   EXHIBIT d(iv)

                         THE GABELLI EQUITY TRUST INC.
                                RIGHTS OFFERING

                DTC PARTICIPANT OVER-SUBSCRIPTION EXERCISE FORM

THIS FORM IS TO BE USED ONLY BY DEPOSITORY TRUST COMPANY PARTICIPANTS TO
EXERCISE THE OVER-SUBSCRIPTION PRIVILEGE IN RESPECT OF RIGHTS WITH RESPECT TO
WHICH THE PRIMARY SUBSCRIPTION WAS EXERCISED AND DELIVERED THROUGH THE
FACILITIES OF THE DEPOSITORY TRUST COMPANY. ALL OTHER EXERCISES OF
OVER-SUBSCRIPTION PRIVILEGES MUST BE EFFECTED BY THE DELIVERY OF THE
SUBSCRIPTION CERTIFICATES.
                      ------------------------------------

THE TERMS AND CONDITIONS OF THE RIGHTS OFFERING ARE SET FORTH IN THE COMPANY'S
PROSPECTUS DATED                , 2000 (THE "PROSPECTUS") AND ARE INCORPORATED
HEREIN BY REFERENCE. COPIES OF THE PROSPECTUS ARE AVAILABLE UPON REQUEST FROM
THE COMPANY AND THE SUBSCRIPTION AGENT.
                      ------------------------------------

VOID UNLESS RECEIVED BY THE SUBSCRIPTION AGENT BY 5:00 PM, NEW YORK CITY TIME,
ON JANUARY   , 2001, UNLESS THE OFFER IS EXTENDED (THE "EXPIRATION DATE").
                      ------------------------------------

1.  The undersigned hereby certifies to the Company and the Subscription Agent
that it is a participant in The Depository Trust Company ("DTC") and that it has
either (i) fully exercised its Rights under the Primary Subscription and
delivered such exercised Rights to the Subscription Agent by means of transfer
to the DTC account of the Subscription Agent or (ii) delivered to the
Subscription Agent a Notice of Guaranteed Delivery in respect of the exercise of
the Rights under the Primary Subscription and will deliver the Rights called for
in such Notice of Guaranteed Delivery to the Subscription Agent by means of
transfer to such DTC account of the Subscription Agent.

2.  The undersigned hereby exercises the Over-Subscription Privilege to
purchase, to the extent available, ____________ shares of Common Stock and
certifies to the Company and the Subscription Agent that such Over-Subscription
Privilege is being exercised for the account or accounts of persons (which may
include the undersigned) on whose behalf all Primary Subscription Rights have
been exercised.

3.  The undersigned understands that payment of the Subscription Price of $
per share for each share of Common Stock subscribed for pursuant to the
Over-Subscription Privilege must be received by the Subscription Agent at or
before 5:00 p.m., New York City time, on the Expiration Date and represents that
such payment, in the aggregate amount of $________, either (check appropriate
box):

     [ ] has been or is being delivered to the Subscription Agent pursuant to
the Notice of Guaranteed Delivery referred to above

               or

     [ ] is being delivered to the Subscription Agent herewith

               or

     [ ] has been delivered separately to the Subscription Agent;

                           (continued on other side)
<PAGE>   2

        and, in the case of funds not delivered pursuant to a Notice of
        Guaranteed Delivery, is or was delivered in the manner set forth below
        (check appropriate box and complete information relating thereto):

     [ ] uncertified check

     [ ] certified check

     [ ] bank draft

------------------------------------
 Primary Subscription Confirmation
               Number

------------------------------------
       DTC Participant Number

------------------------------------
      Name of DTC Participant

For allocation purposes, the total number of record date shares owned by the
persons on whose behalf this Over-Subscription Privilege is being exercised were
________________________.

Registration into which shares, interest and/or refund checks should be issued:

Name:
----------------------------------------------

      ----------------------------------------------------

Address:
--------------------------------------------

       ---------------------------------------------------

       ---------------------------------------------------

Certified TIN:
--------------------------------------

By:
-------------------------------------------------
Name:
Title:

Contact Name:
-------------------------------------

Phone Number:
------------------------------------

Dated:             , 200
</TEXT>
</DOCUMENT>
