Jane L. Mendillo, who worked at Harvard Management Company (HMC) for 15 years until her departure to run Wellesley College's investments in 2002, will return as HMC's CEO this July, the University announced Thursday.

The former vice president of external investments at HMC revamped Wellesley's investment strategy, helping the school's endowment earn an average annual return of 13.5 percent during her five-year tenure, according to a Harvard press release. Wellesley's investments grew by almost a quarter in 2007 and nearly matched HMC's results.

The move comes just over six months after HMC's previous chief, Mohamed A. El-Erian announced he would step down. Robert Kaplan, a former vice chairman at Goldman Sachs and a professor at the Harvard Business School, has acted as interim CEO since January 1 and, the University says, will now serve on HMC's board of directors.

Mendillo still serves on the boards of several other investment groups, according to the announcement, including the Yale University Investment Committee—a post she will leave in June.

When El-Erian assumed leadership of HMC in 2006, the firm was severely in need of rebuilding, having lost more than 30 employees when the previous CEO, Jack R. Meyer left to form his own hedge fund with $500 million in seed money from the University.

But as Mendillo prepares to take the helm, the framework that El-Erian recreated—a setup that added $5.7 billion to Harvard's endowment in 2007—remains in place.

She will officially take the reins of managing Harvard's $34.9 billion endowment on July 1, allowing for a period of transition in which Kaplan can help acclimate her to the new position.

—Check TheCrimson.com for updates.