UNITED STATES
                  SECURITIES AND EXCHANGE COMMISSION
                        Washington, D.C. 20549


                             SCHEDULE 13G

               Under the Securities Exchange Act of 1934


                           (Amendment No. )*


                                MSCI Inc.
                             (Name of Issuer)

                           Class A Common Stock
                      (Title of Class of Securities)

                                55354G100
                              (CUSIP Number)

                            December 31, 2007
         (Date of Event Which Requires Filing of this Statement)


Check the appropriate box to designate the rule pursuant to which this
Schedule is filed:
[X] Rule 13d-1(b)
[ ] Rule 13d-1(c)
[ ] Rule 13d-1(d)


*The remainder of this cover page shall be filled out for a reporting
person's initial filing on this form with respect to the subject class
of securities, and for any subsequent amendment containing information
which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not
be deemed to be "filed" for the purpose of Section 18 of the Securities
Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of
that section of the Act but shall be subject to all other provisions of
the Act (however, see the Notes).


















CUSIP: 55354G100                                                Page 1 of 5



 1   NAMES OF REPORTING PERSONS
     I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (ENTITIES ONLY)
     Capital Group International, Inc.


 2   CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (SEE
     INSTRUCTIONS)                                                 (a)

                                                                    (b)
 3   SEC USE ONLY


 4   CITIZENSHIP OR PLACE OF ORGANIZATION

     California

             5   SOLE VOTING POWER

                  3,050,935


             6   SHARED VOTING POWER
 NUMBER OF
   SHARES         NONE
BENEFICIALL
 Y OWNED BY
             7   SOLE DISPOSITIVE POWER
    EACH
 REPORTING        3,160,235
   PERSON
   WITH:
             8   SHARED DISPOSITIVE POWER

                  NONE

 9   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON

     3,160,235          Beneficial ownership of 299,000 shares are
     disclaimed pursuant to Rule 13d-4


 10  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES
     (SEE INSTRUCTIONS)


 11  PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9

     16.7%

 12  TYPE OF REPORTING PERSON (SEE INSTRUCTIONS)

     HC, CO








CUSIP: 55354G100                                                Page 2 of 5


                  SECURITIES AND EXCHANGE COMMISSION
                         Washington, DC 20549

                             Schedule 13G
               Under the Securities Exchange Act of 1934

Amendment No.

Item 1(a)     Name of Issuer:
       MSCI Inc.

Item 1(b)     Address of Issuer's Principal Executive Offices:
       Wall Street Plaza
       88 Pine Street
       New York NY 10005

Item 2(a)     Name of Person(s) Filing:
       Capital Group International, Inc.

Item 2(b)     Address of Principal Business Office or, if none,
       Residence:
       11100 Santa Monica Blvd.
       Los Angeles, CA  90025

Item 2(c)     Citizenship:   N/A

Item 2(d)     Title of Class of Securities:
       Class A Common Stock

Item 2(e)     CUSIP Number:
       55354G100

Item 3     If this statement is filed pursuant to sections 240.13d-1(b)
       or 240.13d-2(b) or (c), check whether the person filing is a:
       (g)     [X]     A parent holding company or control person in
            accordance with section 240.13d-1(b)(1)(ii)(G).

Item 4     Ownership

       Provide the following information regarding the aggregate
       number and percentage of the class of securities of the issuer
       identified in Item 1.


       (a)    Amount beneficially owned:
       (b)    Percent of class:
       (c)    Number of shares as to which the person has:
       (i)    Sole power to vote or to direct the vote:
       (ii)   Shared power to vote or to direct the vote:
       (iii)  Sole power to dispose or to direct the disposition of:
       (iv)   Shared power to dispose or to direct the disposition of:

       See page 2







CUSIP: 55354G100                                                Page 3 of 5
 

Capital Group International, Inc. ("CGII") is the parent holding company of a group of investment management companies that hold investment power and, in some cases, voting power over certain of the securities reported in this Schedule 13G. The investment management companies, which include a "bank" as defined in Section 3(a)(6) of the Securities Exchange Act of 1934 (the "Act") and several investment advisers registered under Section 203 of the Investment Advisers Act of 1940, provide investment advisory and management services for their respective clients which include registered investment companies and institutional accounts. CGII does not have investment power or voting power over the securities managed for its clients. However, by virtue of Rule 13d-3 under the Act, CGII may be deemed to "beneficially own" 3,160,235 shares or 16.7% of the 18,961,235 shares of Class A Common Stock believed to be outstanding. In addition, CGII owns 2,861,235 Class B shares for its own account. These shares are convertible into Class A shares on a one-to-one basis, and are treated as having been converted into 2,861,235 Class A shares for the purpose of this filing, and are included in the totals above. Item 5 Ownership of Five Percent or Less of a Class. If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following: [ ] Item 6 Ownership of More than Five Percent on Behalf of Another Person: One or more clients of Capital Group International, Inc. have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, the Class A Common Stock of MSCI Inc.. Item 7 Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company or Control Person. 1. Capital Guardian Trust Company is a bank as defined in Section 3(a)(6) of the Act and an investment adviser registered under Section 203 of the Investment Adviser Act of 1940, and a wholly owned subsidiary of Capital Group International, Inc. Item 8 Identification and Classification of Members of the Group: N/A Item 9 Notice of Dissolution of Group: N/A Item 10 Certification By signing below, I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect. CUSIP: 55354G100 Page 4 of 5 Signature After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct. Date: May 8, 2008 Signature: ***David I. Fisher Name/Title: David I. Fisher, Chairman Capital Group International, Inc. ***By /s/ Kristine Nishiyama Kristine Nishiyama Attorney-in-fact Signed pursuant to a Power of Attorney dated December 28, 2007 included as an Exhibit to Schedule 13G filed with the Securities and Exchange Commission by Capital Group International, Inc. on February 1, 2008 with respect to Beazer Homes USA Inc. CUSIP: 55354G100 Page 5 of 5