Snapchat co-founders Evan Spiegel and Bobby Murphy are now worth an estimated $4 billion each, according to a new article from Forbes. Snap Inc., the parent company of Snapchat, is preparing to go public and has a private valuation of $18 billion, of which Spiegel and Murphy have a 22.4% stake in.

According to Forbes, Spiegel will also be receiving an additional 3% stake in the company to “motivate him to continue growing” Snap towards an IPO. Spiegel was the youngest person on Forbes’ list of America’s richest people with an estimated $2.1 billion fortune.