March 18 (Reuters) - Stock market index provider MSCI Inc said it would sell proxy advisory unit Institutional Shareholder Services (ISS) to private-equity firm Vestar Capital Partners for $364 million to focus on its risk investment products and services business.
MSCI said in October that it was exploring a sale or other options for the influential and often-controversial business.
ISS has drawn much criticism in recent times as companies and trade groups such as the U.S. Chamber of Commerce have questioned its methodologies and periodic opposition to management on various high-profile matters.
The unit accounted for about 12 percent of MSCI's total revenue of $267.6 million in the fourth quarter.
ISS has more than 1,700 clients for its corporate governance services, well ahead of competitors such as Glass, Lewis & Co.
The deal is expected to close within the next three months, MSCI said.
Vestar Capital Partners was part of a group that acquired Del Monte Foods in a $5.3 billion deal in 2011. The group included KKR & Co LP and Centerview Capital.
Morgan Stanley served as financial adviser to MSCI and Davis Polk & Wardwell LLP was the legal adviser.
Shares of MSCI closed at $45.62 on the New York Stock Exchange on Monday. They have gained 12 percent since October when it announced its intention to explore options for ISS.