Baiju Bhatt (pictured) and his co-founder Robinhood own about a third of the company, or $1 billion each on paper.  David Paul Morris/Bloomberg
Baiju Bhatt (pictured) and his co-founder Robinhood own about a third of the company, or $1 billion each on paper.  David Paul Morris/Bloomberg

Robinhood founders become billionaires by letting investors trade for free