<PAGE>
EXHIBIT (5) & (23)
June 29, 2000
Merrill Lynch & Co., Inc.
4 World Financial Center
New York, New York 10080
Gentlemen:
As your counsel, we have examined a copy of the Restated Certificate of
Incorporation, as amended, of Merrill Lynch & Co., Inc. (hereinafter called the
"Company"), certified by the Secretary of State of the State of Delaware. We
are familiar with the corporate proceedings had in connection with the proposed
issuance and sale by the Company to the Underwriter named in the Terms Agreement
referred to below, pursuant to an Underwriting Agreement dated August 5, 1998
(the "Underwriting Agreement"), between the Company and Merrill Lynch & Co.,
Merrill Lynch, Pierce, Fenner & Smith Incorporated ("MLPF&S"), as supplemented
by the Terms Agreement dated June 26, 2000 (the "Terms Agreement") between the
Company and MLPF&S (the "Underwriter"), of $42,000,000 aggregate principal
amount of the Company's S&P 500 Market Index Target-Term Securities due June 29,
2007 (the "Securities"). We have also examined a copy of the Indenture between
the Company and The Chase Manhattan Bank as Trustee, dated as of April 1, 1983,
as amended (the "Indenture"), and the Company's Registration Statements on Form
S-3 (File Nos. 333-68747 and 333-38792) relating to the Securities (the
"Registration Statements").
1
<PAGE>
Based upon the foregoing and upon such further investigation as we deemed
relevant in the premises, we are of the opinion that:
1. The Company has been duly incorporated under the laws of the State of
Delaware.
2. The Securities have been duly and validly authorized by the Company and
when the Securities have been duly executed and authenticated in accordance with
the terms of the Indenture and delivered against payment therefor as set forth
in the Underwriting Agreement, as supplemented by the Terms Agreement, the
Securities will constitute valid and legally binding obligations of the Company,
enforceable against the Company in accordance with their terms, except to the
extent that enforcement thereof may be limited by bankruptcy, moratorium,
insolvency, reorganization or similar laws relating to or affecting creditors'
rights generally and except as enforcement thereof is subject to general
principles at equity (regardless of whether enforcement is considered in a
proceeding in equity or at law).
We consent to the filing of this opinion as an exhibit to the Registration
Statements and as an exhibit to the Current Report of the Company on Form 8-K
dated June 29, 2000.
Very truly yours,
/s/ Brown & Wood LLP
2
