Before Robinhood became one of the most loved and most hated stock trading platforms in the U.S., it was just another tech startup, launched by two mathematicians with an audacious idea: make stock trading mobile, make it fun, and make it free—with no commissions, and no minimum balances. In 2013, Vlad Tenev and Baiju Bhatt decided to pursue this idea full-time. They sidelined their first business—selling software that shaved milliseconds off high-speed trades—and began building an app aimed at anyone with a smartphone and a few extra dollars to invest. After launching in 2015, Robinhood steadily attracted users and rave reviews, but soon drew criticism for its business model, which came under even more scrutiny after the GameStop trading frenzy in January. Despite these challenges, Robinhood has grown to 13 million users and is now poised for a lucrative IPO.How I Built This Summit - information and tickets at:http://summit.npr.org