MSCI Inc. (NYSE: MSCI) is buying GMI Ratings for $15 million in cash.

MSCI provides environmental, social and governance ratings and research to institutional investors through its subsidiary, MSCI ESG Research Inc. The deal is expected to close in the third quarter.

MSCI provides investment tools, including indexes, portfolio risk and performance analytics and other data, to asset managers, banks, hedge funds and pension funds. In January 2013, the company agreed to pick up Investor Force Holdings Inc., a provider of performance-measurement software for investment consultants, for $23.5 million. 

Davis Polk & Wardwell LLP acted as MSCI's legal adviser on the deal.

Several companies have recently made deals to acquire investor tools. Earlier in June, private equity firm Genstar Capital agreed to acquire Asset International Inc., which provides data, business intelligence and information services to investment managers.