FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person * COSTER PETER   2. Issuer Name and Ticker or Trading Symbol MARSH & MCLENNAN COMPANIES INC [MMC] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) President, Mercer Inc. (Last) (First) (Middle) 1166 AVENUE OF THE AMERICAS 3. Date of Earliest Transaction (Month/Day/Year) 01/01/2005 (Street) NEW YORK, NY 10036 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 01/01/2005   M   19,800 (1) A $ 0 (2) 242,827.2113 (3) (4) D   Common Stock 01/01/2005   F   10,044 D $ 32.81 232,783.2113 (3) (4) D   Common Stock               485.5616 (5) I Stock Investment Plan (by 401(k))

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Restricted Stk. Units -SISP

(6)

09/30/2004

P

V

618.3826 (7)

(2)

(2)

Common Stock

618.3826

(7)

33,309.7428

D

Restricted Stock Units

(6)

01/01/2005

M

19,800

(2)

(2)

Common Stock

19,800

(2)

96,888

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
COSTER PETER 1166 AVENUE OF THE AMERICAS NEW YORK, NY 10036			President, Mercer Inc.

Signatures

William J. White, Attorney-in-Fact		01/04/2005
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Vesting and distribution of 19,800 Restricted Stock Units of which 10,044 were withheld to cover applicable taxes.
(7)	Reflects additional shares acquired by the Stock Investment Supplemental Plan (SISP) Custodian at prevailing market prices. Information reported herein is based on reporting person's Plan Statement as of September 30, 2004.
(6)	The security converts to MMC Common Stock on a 1-for-1 basis
(3)	Includes 521 shares acquired under the MMC Employee Stock Purchase Plan (the "Plan") and 6.2113 shares acquired under the dividend reinvestment feature of the Plan at prevailing market prices.
(4)	Includes 636,600 shares of MMC Restricted Stock.
(2)	Not Applicable
(5)	Shares acquired by the Stock Investment Plan (SIP) Custodian at prevailing market prices. Information reported herein is based on reporting person's Plan Statement as of September 30, 2004.

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