NEW HAVEN, Conn. (AP) – Yale University President Richard C. Levin, who oversaw a big building and renovation program and an expansion in financial aid programs, announced Thursday he is stepping down at the end of the academic year after 20 years at the Ivy League school.

Levin, 65, has served longer than any other president currently in the Ivy League or the 61-member Association of American Universities. He plans to take a sabbatical and write a book.

READ MORE: Rain Leaks Into Rockefeller Center Station, Riders Call On MTA To Invest In Subway Station Upgrades

He is credited with leading the school’s largest building and renovation program since the 1930s, expanding Yale’s financial aid programs and international activities, improving the university’s historically difficult relationship with its unions and building partnerships with New Haven.

Yale’s endowment went from $3.2 billion in 1993 when Levin was named president to $19.4 billion this year. Levin helped raise more than $7 billion during his tenure, Yale officials said.

Under Levin, the university secured long term contracts with unions. A homebuyers program started in 1994 offered financial incentives to Yale employees to buy homes in the city and more than 1,000 Yale faculty and staff have participated, Yale officials said.

Yale renovated all 12 of its residential colleges and has plans to build two more. About 70 percent of the space on campus has been partially or comprehensively renovated since 1993.

A planned joint campus with the National University of Singapore will open next year.

READ MORE: Candidate Conversations: Eric Adams

“Rick Levin is simply one of the world’s great leaders,” Yale trustee Indra Nooyi, chief executive of PepsiCo, said in a statement. “He has been transformational in envisioning how a university should be a leading citizen in its home community and he has boldly staked out how the leading universities should become global institutions. His example has been a guide for how universities around the world can have a much greater impact.”

Yale Corp., the university’s governing body, will conduct a search.

Levin wrote in a message to the Yale community that he was looking forward to a sabbatical, “when at last I will have the time to complete a book of reflections on higher education and economic policy.”

Levin, who was born and raised in San Francisco, met his wife Jane at Yale. “From the day Jane and I entered graduate school in 1970, Yale has been our life,” Levin wrote in his message.

He was an economics professor when he was tapped to become president in 1993. His wife is a senior lecturer.

The last Yale president to serve 20 years was Arthur Twining Hadley, who took office in 1899.

MORE NEWS: Supply Chain Issues: 'There Really Are Problems Everywhere,' Even For Small Companies

(TM and Copyright 2012 CBS Radio Inc. and its relevant subsidiaries. CBS RADIO and EYE Logo TM and Copyright 2012 CBS Broadcasting Inc. Used under license. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.)