Some dropped out to focus on their companies, like Facebook CEO Mark Zuckerberg, while others made their fortunes long after leaving school, like Uber cofounder Travis Kalanick. These billionaires dropped out of a wide variety of schools, from Harvard to UCLA to The City College of New York.

Approximately 1 in 8 billionaires on the 2018 Forbes 400 ranking of the wealthiest people in America was a college dropout, Business Insider’s Rachel Premack previously reported.

Keep reading to meet 13 billionaires who also happen to be college dropouts.

Fashion designer Ralph Lauren dropped out of Baruch College at The City College of New York.

Ralph Lauren
Ralph Lauren. Gilbert Carrasquillo / Contributor / Getty Images

The 79-year-old designer founded his eponymous fashion company by selling ties out of his desk drawer while working in an office in the Empire State Building, according to the company’s website.

Called “the man who made American fashion cool” by Forbes, Lauren currently has a net worth of $5.8 billion — and he only finished two years of college.

WhatsApp cofounder and former CEO Jan Koum dropped out of San Jose State University.

jan koum
Jan Koum. David Ramos / Getty Images

Koum worked at Yahoo for nine years before founding WhatsApp, Business Insider previously reported in May 2017.

The 43-year-old computer programmer has a net worth of $10 billion, Forbes estimates.

Mark Zuckerberg left Harvard after his sophomore year to focus on Facebook.

Mark Zuckerberg
Mark Zuckerberg. Getty

Zuckerberg founded the social network to help fellow students learn the names of the people in their classes, Business Insider previously reported. He dropped out shortly after.

The 35-year-old entrepreneur has a current net worth of $66 billion, Forbes estimates.

Las Vegas Sands CEO Sheldon Adelson dropped out of the City College of New York.

Sheldon Adelson
Sheldon Adelson. Sheldon Adelson.Shahar Azran / Contributor / Getty Images

Adelson first became wealthy after founding a company called COMDEX that hosted technology-focused trade shows, Business Insider previously reported in May 2019. In 1995, Adelson and his partners sold it along with other smaller shows to SoftBank for $862 million.

The 86-year-old has a net worth of $33.1 billion, Forbes estimates.

CNN founder Ted Turner left Brown University before graduating … but not by choice.

ted turner
Ted Turner. AP Photo/John Bazemore

Turner was expelled from Brown for allowing his girlfriend to live with him in his dorm room, Business Insider previously reported. Despite the rather murky end to Turner’s time as a student there, the university issued him honorary degrees years later.

The 80-year-old has a net worth of $2.2 billion, Forbes estimates.

Ty Warner, the creator of Beanie Babies, dropped out of Kalamazoo College in 1962 because he couldn’t afford it, according to the Chicago Tribune.

ty warner
Ty Warner. AP Images/Louis Lanzano

Warner went on to sell encyclopedias, work as a valet, and sell stuffed animals for now-defunct toy company Dakin before founding Ty Inc. and creating the iconic Beanie Baby, according to HuffPostForbes reports that Warner also owns several hotels, including the Four Seasons in New York.

But Warner’s career wasn’t without controversy. He pled guilty to charges of tax evasion in 2017 for hiding income in a Swiss bank, according to HuffPost.

The 74-year-old now has a net worth of $2.6 billion, Forbes estimates.

DreamWorks Animation cofounder David Geffen once lied about having graduated from UCLA to keep a job in the mailroom of now-defunct talent agency William Morris.

david geffen
David Geffen. AP Photo/Jason DeCrow

Geffen later admitted publicly that he had actually dropped out of the University of Texas at Austin, according to Forbes. He worked as a talent agent at William Morris prior to founding DreamWorks.

The 76-year-old is now the richest man in Hollywood, and Forbes estimates that his net worth is about $8.4 billion.

Michael Dell dropped out of the University of Texas at Austin to sell computers.

Micheal Dell
Michael Dell. Dell

As a student, Dell spent his spare time upgrading PCs and selling them from his dorm room, Business Insider previously reported in November 2018. He made $180,000 in his first month of business the summer after his freshman year and never went back to school.

The 54-year-old has a current net worth of $30.6 billion, Forbes estimates.

Oracle founder Larry Ellison dropped out of two different universities.

Larry Ellison
Larry Ellison Larry Ellison. Kimberly White/Getty Images

Ellison enrolled in the University of Illinois at Urbana-Champaign after high school but dropped out during his sophomore year after his adoptive mother died, Business Insider previously reported. He later completed one semester at the University of Chicago.

The 75-year-old has a net worth of $63 billion, according to Forbes.

Bill Gates left Harvard after two years to found Microsoft.

bill gates
Bill Gates. John Lamparski/Getty Images

In 2010, The Harvard Crimson called Gates “Harvard’s most successful dropout.” He left the Ivy League school during his sophomore year in 1975.

The 63-year-old is worth $102 billion, according to Forbes.

Uber cofounder and former CEO Travis Kalanick studied computer engineering at UCLA before dropping out to work on now-defunct search engine Scour.

Travis Kalanick
Travis Kalanick. Getty

After Scour filed for bankruptcy, Kalanick also founded a networking-software company called Red Swoosh. Kalanick sold Red Swoosh to Akamai for $23 million in 2007, Business Insider previously reported. He used some of that money to spend a year traveling the world before founding Uber.

The 43-year-old has a net worth of $3.7 billion, Forbes estimates.

Donald Newhouse dropped out of Syracuse University to join his family’s publishing business.

Donald Newhouse
Donald Newhouse. Ben Gabbe/Getty

Newhouse went on to build that business, Advance Publications, into a media empire. The company now owns numerous television stations, newspapers, and magazine publisher Conde Nast, Forbes reports.

Newhouse, 90, now has a net worth of $12.8 billion, according to Forbes, and in 2016, he returned to Syracuse to accept an honorary degree and deliver a commencement speech to that year’s graduating class.

Carnival Corp. chairman Micky Arison dropped out of the University of Miami to help his father found their now-famous cruise line.

Micky Arison
Micky Arison. Mike Ehrmann/Getty Images

The first position Arison ever held at Carnival was sales representative. He went on to serve as the company’s CEO for 34 years, according to Forbes.

Arison, 70, has a net worth of $7.7 billion, Forbes estimates.