8-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C.  20549

_____________________

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the

Securities Exchange Act of 1934

Date of report (Date of earliest event reported) August 16, 2010

Marsh & McLennan Companies, Inc.

(Exact Name of Registrant as Specified in Charter)

Delaware	1-5998	36-2668272
(State or Other Jurisdiction of Incorporation)	(Commission File Number)	(IRS Employer Identification No.)

1166 Avenue of the Americas, New York, NY	10036
(Address of Principal Executive Offices)	(Zip Code)

Registrant’s telephone number, including area code (212) 345-5000

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

o Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

o Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

o Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

o Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Item 8.01            Other Events

The following documents are filed with reference to the Registration Statement (No. 333-163405) on Form S-4 (the “Registration Statement”), filed by Marsh & McLennan Companies, Inc. with the Securities and Exchange Commission on November 30, 2009. Such documents are filed in connection with the issuance of shares under the Registration Statement pursuant to a post-closing purchase price adjustment provision contained in a Stock Purchase and Plan of Reorganization dated March 16, 2010.

Item 9.01            Financial Statements and Exhibits

(d)        Exhibits

5.1        Opinion of the Deputy General Counsel of Marsh & McLennan Companies, Inc.

23.1 Consent of the Deputy General Counsel of Marsh & McLennan Companies, Inc. (contained in Exhibit 5.1).

2

SIGNATURES

      Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

MARSH & McLENNAN COMPANIES, INC.
By:	/s/ Luciana Fato
Name:	Luciana Fato
Title:	Deputy General Counsel &
	Corporate Secretary

Date: August 16, 2010

3

EXHIBIT INDEX

Exhibit No.         Exhibit

5.1        Opinion of the Deputy General Counsel of Marsh & McLennan Companies, Inc.

23.1 Consent of the Deputy General Counsel of Marsh & McLennan Companies, Inc. (contained in Exhibit 5.1).

4

EX-5.1

  Luciana Fato Deputy General Counsel & Corporate Secretary   Marsh & McLennan Companies, Inc. 1166 Avenue of the Americas New York, New York 10036-2774 212 345 3286

Exhibit 5.1

August 16, 2010

Marsh & McLennan Companies, Inc.

1166 Avenue of the Americas

New York, New York 10036

Re: Registration Statement on Form S-4 (Registration No. 333-163405)

Ladies and Gentlemen:

I am the Deputy General Counsel and Corporate Secretary of Marsh & McLennan Companies, Inc., a Delaware corporation (the “Company”), and, as such, have acted as internal counsel to the Company in connection with the transaction contemplated under an Stock Purchase and Plan of Reorganization (the “Purchase Agreement”) dated as of March 16, 2010.

In connection with rendering the opinions expressed below, I have examined (i) the Registration Statement on Form S-4 (Registration No. 333-163405) of the Company, for the registration of the Company’s common stock, par value $1.00 per share (the “Common Stock”), filed with the Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933, as amended (the “Securities Act”), on November 30, 2009; (ii) the core prospectus dated December 15, 2009, forming a part thereof, together with the documents incorporated therein by reference; and (iii) the Purchase Agreement, pursuant to which the shares of Common Stock (the “Shares”) will be issued on August 16, 2010.

I have examined originals or certified, conformed or reproduction copies of such records of the Company, such certificates of officers of the Company and of public officials, and such other documents, and have made such investigations of law, as I have deemed necessary or appropriate as the basis for the opinions set forth below.  In all such examinations, I have assumed without investigation the legal capacity of all natural persons executing documents, the genuineness of all signatures on original or certified copies, the authenticity of all original or certified copies and the conformity to original or certified documents of all copies submitted to me as conformed or reproduction copies.

Based upon the foregoing examination and in reliance thereon, and subject to the assumptions stated and in reliance on statements of fact contained in the documents that I have examined, I am of the opinion that the Shares, when delivered against payment

Page 2

August 16, 2010

Marsh & McLennan Companies, Inc.

therefore pursuant to the Share Purchase Agreement, will be legally issued, fully paid and non-assessable.

I consent to the filing of this opinion as an exhibit to the Company’s Form 8-K.  In giving this consent, I do not thereby admit that I am within the category of persons whose consent is required under Section 7 of the Securities Act or the Rules and Regulations of the Commission.

 Very truly yours,

/s/ Luciana Fato& #160;

 Luciana Fato

 Deputy General Counsel & Corporate Secretary