Instagram CEO Kevin Systrom is the latest app creator to join Forbes’ billionaires list just as Facebook stock rises. However, Systrom’s rise to billionaire status was no easy fete.

Initially the programmer sold his photo sharing app to Facebook creator and CEO, Mark Zuckerberg, back in 2012 for a whopping $300 million in cash and 23 million shares of stock – totaling the company’s worth to a cool $1 billion before Facebook’s May 2012 IPO.

It was a sweet deal for Instagram as the app had 30 million users without generating revenue at the time. However, by the time the deal closed, Systrom’s arrangement with Zuckerberg changed due to plummeting Facebook stock in Sept. 2012. Consequently, the deal ended up being worth $715 million, driving Systrom’s adjusted net worth down to $280 million.

But things have changed quite tremendously for the 32-year-old CEO.

In the past four years, Facebook’s stock has increased 500%, which has, in-turn, brought Systrom a $1.1 billion fortune from the Instagram deal. Not to mention, he has also been gifted a small amount of Wal-Mart stock now, which was part of a deal created back in September 2014 when Systrom joined Wal-Mart’s board.

Instagram’s worth has also increased over the past four years. With more than 500 million users now, Forbes projected the company would be worth around $50 billion had it not been acquired by Zuckerberg back in 2012.

Systrom isn’t the only app-creator gracing Forbes’ billionaires list with Zuckerberg. Below are a few other application money-makers that have landed on Forbes’ billionaires list.

Travis Kalanik Travis Kalanik created Uber. Photo: Getty

Travis Kalanick – Uber

Garrett Camp Garrett Camp created Uber. Photo: Getty

Garrett Camp – Uber

Evan Speigel Evan Speigel created Snapchat. Photo: Getty

Evan Spiegel – Snapchat

Bobby Murphy Bobby Murphy created Snapchat. Photo: Getty

Bobby Murphy – Snapchat

Jack Dorsey Jack Dorsey created Twitter. Photo: Getty

Jack Dorsey – Twitter

Jan Koum Jan Koum created WhatsApp. Photo: Getty

Jan Koum - WhatsApp