A real bro keeps his promise. And that's what Nick Woodman did. The self-made billionaire founder and CEO of GoPro is worth an estimated $2.3 billion since GoPro went public in June 2014. Woodman paid his college roommate a huge sum, and it was all from a promise made 10 years ago.

He returned 4.7 million shares to GoPro so that his college roommate, Neil Dana, could cash in around $229 million. According to Bloomberg:

The GoPro Inc. founder returned 4.7 million shares to the San Mateo-based camera maker on May 11, according to a regulatory filing. He agreed in 2011 to repay the company for stock options it granted to Neil Dana, who attended the University of California at San Diego with Woodman and was GoPro employee No. 1.

Woodman, 39, vowed in the development phase of the 10-year-old company to give Dana 10 percent of any proceeds he received from the sale of the company’s shares, according to the company’s 2014 prospectus. To cancel this agreement, GoPro issued Dana more than 6 million fully-vested options in June 2011 and 270,000 restricted stock units six months later. Woodman agreed to reimburse the company when the options were exercised.

Dana, who is GoPro’s director of music and specialty sales, spent $3.6 million to exercise his options, according to data compiled by Bloomberg. They were valued at $229 million at the close of trading on Monday.

A bro always keeps his word.