<PAGE>
[Letterhead of Cahill Gordon & Reindel]
September 13, 2000
Prudential Securities Incorporated
One Seaport Plaza
New York, New York 10292
Re: National Equity Trust,
Forbes Forty Index Trust Series 4
Gentlemen:
We have acted as special counsel for you as Depositor of the National
Equity Trust, Forbes Forty Index Trust Series 4 (the "Trust"), in connection
with the issuance under the Trust Indenture and Agreement, dated April 25, 1995,
and related Reference Trust Agreement, dated September 13, 2000 (such Trust
Indenture and Agreement and Reference Trust Agreement collectively referred to
as the "Indenture"), among you, as Depositor and The Chase Manhattan Bank, as
Trustee, of units of fractional undivided interest in said Trust (the "Units")
comprising the Units of National Equity Trust, Forbes Forty Index Trust Series
4. In rendering our opinion expressed below, we have relied in part upon the
opinions and representations of your officers and upon opinions of counsel to
Prudential Securities Incorporated.
<PAGE>
-2-
Based upon the foregoing, we advise you that, in our opinion, when the
Indenture has been duly executed and delivered on behalf of the Depositor and
the Trustee and when the Receipt For Units evidencing the Units has been duly
executed and delivered by the Trustee to the Depositor in accordance with the
Indenture, the Units will be legally issued, fully paid and nonassessable by the
Trust, and will constitute valid and binding obligations of the Trust and the
Depositor in accordance with their terms, except that enforceability of certain
provisions thereof may be limited by applicable bankruptcy, insolvency,
reorganization, moratorium or other similar laws affecting creditors generally
and by general equitable principles.
We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement (File No. 333-44296) relating to the Units referred to
above and to the use of our name and to the reference to our firm in said
Registration Statement and the related Prospectus. Our consent to such reference
does not constitute a consent under Section 7 of the Securities Act, as in
consenting to such reference we have not certified any part of the Registration
Statement and do not otherwise come within the categories of persons whose
consent is required under said Section 7 or under the rules and regulations of
the Commission thereunder.
Very truly yours,
Cahill Gordon & Reindel
