MSCI (MSCI) S-3ASR Automatic shelf registration

Exhibit 15.1

To the Board of Directors and Shareholders of MSCI Inc.:

We have reviewed, in accordance with the standards of the Public Company Accounting Oversight Board (United States), the unaudited condensed consolidated financial information of MSCI Inc. and subsidiaries as of March 31, 2012 and for the three-month periods ended March 31, 2012 and March 31, 2011, and have issued our report dated May 4, 2012. As indicated in such report, because we did not perform an audit, we expressed no opinion on that information.

We are aware that our report referred to above, which is included in your Quarterly Report on Form 10-Q for the quarter ended March 31, 2012, is being incorporated by reference in this registration statement.

We also are aware that the aforementioned report, pursuant to Rule 436(c) under the Securities Act of 1933, is not considered a part of the registration statement prepared or certified by an accountant or a report prepared or certified by an accountant within the meaning of Sections 7 and 11 of that Act.

/s/ Deloitte & Touche LLP

New York, New York

May 18, 2012