Richard Branson was 15 when he dropped out of school to run a magazine.

On a recent episode of the “Armchair Expert” podcast hosted by Dax Shepard and Monica Padman, the Virgin Group founder said the billionaire made the decision for a simple reason: He knew he could make money at it.

By cold-calling companies and asking them to take out advertisements against their competitors, Branson raised $3,000 to $4,000 for his Student Magazine, he said. The headmaster at Branson’s school was taken aback by his persuasiveness and offered a prediction and a warning.

″[I knew] I could pay for the printing of the paper and manufacturing, and so I quit school … with the headmaster saying, ‘You’re either going to prison or you’re going to become a millionaire,’” Branson, 72, said on the podcast.

Branson hasn’t spent any time behind bars, but he has an estimated net worth of $3.5 billion, as of Thursday morning. His entrepreneurial empire has expanded past his teenage magazine to include airlines, casinos, hotels, and more.

Branson said he started Student Magazine because he felt the traditional curriculum wasn’t teaching him anything relevant.

“There are a lot of things I love to learn about, but not the things that the maths teachers are teaching me or the French teachers are teaching me,” Branson said. “Because of it, I ended up starting a magazine, which gave young people a voice out of the frustration.”

In a 2019 blog post, Branson wrote that dyslexia is often associated with high levels of creativity and problem-solving abilities.

“These are also skills that are going to be urgently needed in the new world of work,” he added. “Problem-solving, creativity and imagination will be in high demand with the rise of AI and automation.”

Of course, it takes more than that to build a business empire after dropping out of school at age 15. At a base level, you need to identify goods or services people want and find a way to monetize them.

“I learned at a young age the importance of ... bringing out the best in people,” Branson said. “What I did realize was that I needed to surround myself with people who were better at things which I was not good at, because of my dyslexia.”