Editor's Note: Inc.'s 12th annual 30 Under 30 list features the young founders taking on some of the world's biggest challenges. Here, meet Robinhood.

Without a seconds hesitation, Vladimir Tenev can tell you the first time he invested in the stock market. He was just 12 but he was bullish on Palm, the maker of the PalmPilot, a hunch that earned him $1,000. That enthusiasm for mobile tech and the stock market led him to Robinhood, Tenev's startup, co-founded with Baiju Bhatt in 2013.

Robinhood is a commission-free brokerage that lets you trade from a smartphone app. "If you're someone who's in your late teens or early 20s and you want to invest a hundred bucks to try out for the first time, it [used to be] cost prohibitive." says Tenev. "What we release allows all those people who were underserved by the previous generation of products to get started much sooner and with smaller amounts of money." Tenev's app has lured enough young users to force older rivals like E-Trade and Charles Schwab to cut fees--the same way those firms forced Wall Street wirehouse firms such as Merrill Lynch to reprice trades.

Robinhood is valued at $1.3 billion and has raised $176 million over four rounds of funding from notable Silicon Valley venture capital firms like New Enterprise Associates and Andreessen Horowitz, and from celebrity investors like Ashton Kutcher, Jared Leto, Snoop Dogg, and John Legend.

More than two million people now use the app to invest in Wall Street. And just as Tenev and his co-founder had predicted, most Robinhood users are young; the average customer is 29. Customers often congregate and discuss investment strategies through such online communities as Facebook and Reddit.

"Legacy investing tools often have interfaces rooted in stocks being bought and sold in the glory years of '90s day trading and are absolutely cumbersome to use," said Johnny Won, founder of tech consulting firm Hyperstop. "Robinhood matters quite a bit when an entirely new kind of financial investor wants to invest in the stock market, unencumbered by what's been done before."

To make trading on a small screen an enjoyable and simple experience, Robinhood has made design a top priority. As a result, users can buy and sell stocks with a simple tap of their thumbs on their smartphones or the Apple Watch. "As one of the early leaders of design mixing with mobile and finance, Robinhood's an absolute standout in ease of use and cutting-edge modern banking," Won says.

With so much of stock trading now done electronically, Tenev said Robinhood did not think that was a service worth charging users for. "It's very similar to sending an email, so the idea that you have the giant incumbents charging $7 to $10 just seemed preposterous to us," Tenev says.

Robinhood has not disclosed its revenue figures or just how many of its accounts are active users, but already, the company has left its mark. The company is focused on making money by providing premium features to its heavy-duty users through a $10 per month subscription service called Robinhood Gold, which was launched in September 2016. The service gives users features such as the ability to do pre and after-hours trading.

It's unclear just how much demand there will be for this product, but the company says it is on a "clear path toward profitability after launching Robinhood Gold." Tenev adds, "the people who are using us are going to stick around."

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