Robinhood has since built a platform that allows other developers to offer zero-fee trades in their own apps. Last year, it launched its primary revenue stream, a $10 per month premium Robinhood Gold option. That allows users to skip the three-day waiting period for deposits and make trades instantly, as well as borrow up to double the amount of money in their account to trade on margin with leverage. Sources say Robinhood Gold has sold better than expected, which likely gave it the momentum for this big raise as investors seek to ‘pour gasoline on the fire’. Robinhood’s status was further bolstered by the fact that established brokerage Charles Schwab reduced its fees in February.

https://techcrunch.com/2017/03/31/now-whos-the-rich/