Ownership Submission
FORM 3
 UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF 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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(Print or Type Responses)
1. Name and Address of Reporting Person *
  MOCZARSKI ALEXANDER S
 2. Date of Event Requiring Statement (Month/Day/Year)
04/20/2011		 3. Issuer Name and Ticker or Trading Symbol
MARSH & MCLENNAN COMPANIES, INC. [MMC]
(Last)
(First)
(Middle)
1166 AVENUE OF THE AMERICAS		 4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
President & CEO, Guy Carpenter
 5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

NEW YORK, NY 10036		 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 Beneficially Owned
1.Title of Security
(Instr. 4)		 2. Amount of Securities Beneficially Owned
(Instr. 4)		 3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5)		 4. Nature of Indirect Beneficial Ownership
(Instr. 5)
Common Stock 49,269
D
 

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 4)		 2. Date Exercisable and Expiration Date
(Month/Day/Year)		 3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4)		 4. Conversion or Exercise Price of Derivative Security 5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)		 6. Nature of Indirect Beneficial Ownership
(Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares
Restricted Stock Units   (1)   (1) Common Stock 29,116 $ (2) D  
Stock Options (Right to Buy)   (3) 03/16/2014 Common Stock 9,524 $ 27.86 D  
Stock Options (Right to Buy)   (4) 03/15/2015 Common Stock 50,000 $ 30.505 D  
Stock Options (Right to Buy)   (5) 03/14/2016 Common Stock 19,050 $ 30.215 D  
Stock Options (Right to Buy)   (6) 02/11/2017 Common Stock 5,963 $ 29.6 D  
Stock Options (Right to Buy)   (7) 02/21/2020 Common Stock 61,856 $ 22.705 D  
Stock Options (Right to Buy)   (8) 02/20/2021 Common Stock 22,489 $ 30.595 D  
Stock Options (Right to Buy) 07/01/2007 03/20/2012 Common Stock 3,612 $ 27.86 D  
Stock Options (Right to Buy) 07/01/2007 03/19/2013 Common Stock 7,500 $ 27.86 D  

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
MOCZARSKI ALEXANDER S
1166 AVENUE OF THE AMERICAS
NEW YORK, NY 10036		       President & CEO, Guy Carpenter  

Signatures

/s/ Lucy Fato, Attorney-in-Fact 04/22/2011
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 5(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) Not Applicable.
(2) The security converts to Marsh & McLennan Companies common stock on a 1-for-1 basis.
(3) These options vested in two installments as follows: 7,143 on July 1, 2007 and 2,381 on March 17, 2008.
(4) These options vested in four equal annual installments on March 16th of 2006, 2007, 2008, and 2009. These options become exercisable only if, after they are vested, the closing price of Marsh & McLennan Companies common stock is at least 15% higher than the exercise price of the options for ten consecutive trading days.
(5) These options vested in four equal annual installments on March 15th of 2007, 2008, 2009, and 2010. These options become exercisable only if, after they are vested, the closing price of Marsh & McLennan Companies common stock is at least 15% higher than the exercise price of the options for ten consecutive trading days.
(6) These options vested in four equal annual installments on February 12th of 2008, 2009, 2010, and 2011. These options become exercisable only if, after they are vested, the closing price of Marsh & McLennan Companies common stock is at least 15% higher than the exercise price of the options for ten consecutive trading days.
(7) These options vest in four equal annual installments on February 22nd of 2011, 2012, 2013 and 2014.
(8) These options vest in four equal annual installments on February 21st of 2012, 2013, 2014 and 2015.

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