On August 18, 2023, Jennifer H. Mak informed MSCI Inc. (?MSCI? or the ?Company?) of her intention to resign as Global Controller, Head of Finance Operations and principal accounting officer of the Company, to pursue another opportunity. Her resignation was not the result of any disagreement with the Company on any matter relating to the Company?s financial statements, internal controls, operations, policies, or practices.

Ms. Mak will remain with the Company through September 7, 2023 to help facilitate the transition of her responsibilities. In connection with Ms. Mak?s resignation, Andrew C. Wiechmann, the Company?s Chief Financial Officer, will assume the responsibilities of principal accounting officer on an interim basis, effective August 24, 2023. No new compensatory arrangements will be entered into with Mr. Wiechmann in connection with his assuming the responsibilities as the Company?s interim principal accounting officer.