Entrepreneurs like Richard Branson and rapper Jay-Z have two things in common: both are wildly successful billionaires, and both never graduated from high school.

But they aren’t the only billionaires who never so much as picked up a high school diploma. While a number of prominent college dropouts later became ultra-wealthy – particularly tech titans like Mark Zuckerberg and Bill Gates – it’s generally rarer for high school dropouts to become among the richest people in the world. But still, it does happen from time to time – as these examples each prove.

Keep reading to learn more about five of the most prominent billionaires who also happen to be high school dropouts.

Zhou Qunfei dropped out of high school at 16 to work in a watch lens factory

Attending accounting classes at night, Zhou Qunfei saved up nearly HK$20,000 (about US$2,500) and eventually opened up her own watch lens company, run by herself and her family members.

She is now the CEO of Lens Technology, which manufactures glass for brands such as Apple, Samsung and Tesla. In 2015, the company went public and Zhou’s stake in the business was worth US$7.2 billion, The New York Times reported that year.

“I have encountered many difficulties and setbacks as an entrepreneur,” she said in an interview with CNBC Make It. “But the key to success is to persevere, especially during the most difficult times.”

The self-made billionaire is currently worth about US$6.6 billion, according to Forbes real-time assessment.

Amancio Ortega dropped out of school at 14 to begin running errands for local shopkeepers

Francois Pinault, founder of the luxury group Kering, dropped out of school when he was 11 years old to work in his father’s timber mill

Jay-Z attended the George Westinghouse Career and Technical Education High School but never graduated

While he personally managed to find immense success after dropping out of high school, the role-model rapper encourages people to take their education seriously.

“Education is super important,” Jay-Z said in a press conference for a performance at Carnegie Hall. “I don’t have a high school diploma or a college diploma, but still for me to articulate, I had to have some form of schooling to articulate my thoughts.”

Richard Branson dropped out of high school when he was only 16 after struggling with dyslexia