The platform's value has risen almost 50 per cent since before the pandemic as the boom in retail investing this year thrusts the company and its founders into the spotlight.
That is despite a crushing setback in February and March when the company's technology seized up, with a series of outages stranding users from the markets during some of the most volatile days of trading since the financial crisis.
Angry customers blasted the company online and overwhelmed its support facilities, while lawsuits quickly emerged aiming to recoup losses — a boon to established rivals such as Charles Schwab and E-Trade that Robinhood has tried to displace.
But the incident is now a fading memory. Customers are flocking to the platform — three million in the first quarter, bringing its user base to 13 million.
Robinhood has become synonymous with the boom in retail investing that has drawn millions of people to the markets — many for the first time — to join the roaring rally that began in March and this week pushed the S&P 500 to an all-time high.
As a student Tenev was "bright and extremely interested" but also "slightly disorganised", with bursts of progress punctuated by distractions, according to Larry Guth, a maths professor at MIT who taught him at Stanford.
Bhatt was a maths whizz but was also known as a "music expert and an incredible band leader as part of a group called The Institute for the Advancement of Funk and Soul", said Josh Constine, an investor at venture capital firm SignalFire and friend to both founders.
The surging value of the company has confirmed the co-chief executives' super-rich status, with each reported to hold stakes in the company worth more than US$1bn.
The pair have said they took inspiration from the Occupy Wall Street protests, which they attended while working in New York in 2012. Robinhood often states its aim is to "democratise finance" by reducing the cost of accessing the markets.
"We didn't build Robinhood to make the rich people richer," Bhatt told the Financial Times in 2016. "The mission is to help the everyman, the rest of us."
Robinhood makes most of its money by selling users' orders to market makers including Citadel Securities, a Wall Street titan majority-owned by billionaire hedge fund manager Ken Griffin. Citadel makes money on the difference between the price to buy and sell the stocks and options, known as the spread.
"They're sleeping with the enemy in some respects," said one Wall Street executive who has often dealt with the pair.
"There is a little bit of an oxymoron by calling it Robinhood . . . the company is worth US$11.2bn — it's not a charity, that's for sure."
Jan Hammer, a partner at Index Ventures who led the group's first funding rounds and is a Robinhood board member, was attracted by the pair's idea to target young financial novices.
They wanted to reach a "new group of people who haven't engaged much with financial products or were disheartened with the world of finance post the financial crisis", Hammer said.
In June the company came under fire when Alex Kearns, a 20-year-old student from the suburbs of Chicago, took his own life after wrongly believing he had lost nearly three quarters of a million dollars on an options trade on the platform. In a note left for his family he blasted Robinhood.
Kearns' death sparked criticism that Robinhood was encouraging risky behaviour among young, inexperienced investors with its sleek interface, alerts and confetti when users complete their first trade, and the founders committed to review elements of the platform.
"When Baiju and I first started building Robinhood, people told us we were trying to achieve the impossible," Tenev told the Financial Times. Pointing to the trading commissions that dominated the industry until they disappeared last year in a move partly attributed to Robinhood, he added: "Our model has been a catalyst."
Written by: Richard Henderson in New York and Miles Kruppa in San Francisco.
