Among the world’s most prestigious universities, Harvard was established in 1636, making it the nation’s oldest university. The private research university in Cambridge, Massachusetts, has graduated eight U.S. presidents and many heads of foreign states, along with countless Rhodes scholars and Nobel laureates. While famous ex-Harvard students such as Bill Gates and Mark Zuckerberg have incredible success stories, they in fact did not graduate from the prestigious university. Harvard claims more billionaires as alumni than any other university, and many of them prefer to stay out of the spotlight.

Leonard Blavatnik

Born in Ukraine, Leonard Blavatnik immigrated to the United States with his family in 1978 after studying railway engineering at Moscow State University. Once in the United States, Blavatnik earned a master’s degree in computer science before attending Harvard, where he earned his MBA in 1989. Before graduating from Harvard, he founded Access Industries, a privately held company that Blavatnik has grown into a diversified empire with operations in natural resources and chemicals, media and telecommunications, and real estate.

In 2011, the company bought Warner Music Group in an all-cash deal worth $3.3 billion. Blavatnik has remained loyal to his alma mater, donating $50 million to Harvard in 2013 to encourage life sciences entrepreneurship. Worth an estimated $16.8 billion, Blavatnik owns properties in London, New York, the Hamptons, Paris, the French Riviera, Anguilla, the Bahamas, Connecticut and Montana. The billionaire splits most of his time between New York City and London, where his palatial home is valued at over $315 million.

Gerald Chan

Gerald Chan prefers to avoid the spotlight, so much he has been referred to as Boston’s invisible billionaire. Born in Hong Kong, his parents sent him and his brother to the United States in 1967 when he was just 16 years old. Without a high school diploma, the only college that would accept him was a small engineering school in Los Angeles. He transferred to UCLA, where he earned his bachelor’s and master’s degrees in engineering. Chan then headed east to Harvard’s School of Public Health in 1973, earning another master’s in medical radiological physics. Still not done, Chan earned his fourth college degree in 1979, a doctorate in biology from Harvard’s Dana-Farber Cancer Institute.

During Chan's doctoral studies, his father, who had started a successful real estate business in Hong Kong, gave him money to invest. Chan purchased a $145,000 home near the Harvard campus and more than tripled his investment, selling it for nearly $450,000 five years later. Chan has continued investing in real estate, spending over $100 million on Boston area buildings through a number of shell companies. Gerald and his brother Ronnie started a private equity and venture capital investment firm, Morningside Group, which Gerald oversees while his brother is at the helm of the Hang Lung Group in Hong Kong. The two brothers have a combined net worth of $2 billion.

In 2014, Chan donated $350 million to Harvard's public health school, which was renamed the Harvard T.H. Chan School of Public Health after Chan’s late father. It was the first time Harvard named one of its schools after a benefactor since 1639.

John Paulson

Born in Queens, New York, John Paulson earned his undergraduate degree in finance from NYU in 1978 before moving on to Harvard Business School on a prestigious Sidney J. Weinberg/Goldman Sachs scholarship. He graduated as a George F. Baker Scholar in the top 5% of his class in 1980. Paulson spent time at Boston Consulting Group and Bear Stearns before starting his own investment firm, Paulson & Co., in 1994.

Paulson became a legendary hedge fund manager by short-selling subprime mortgages and betting on the collapse of the mortgage-backed securities (MBS) market in 2007 and 2008. While the U.S. housing market was crumbling, Paulson earned a staggering $3.5 billion in 2007 alone. In 2015, Paulson made the largest donation in Harvard’s history, surpassing Chan’s gift by donating $400 million to support the university’s School of Engineering and Applied Sciences, which was renamed in his honor. As of late April 2016, Paulson’s net worth was $9.8 billion.