The head of the Robinhood trading platform has apologised to customers at a US congressional hearing prompted by last month’s GameStop trading frenzy.
Vlad Tenev said the situation the firm faced in January – when it limited purchases of certain stocks, sparking outrage – was “unacceptable to us”.
“We are doing everything we can to make sure this won’t happen again,” he said.
Lawmakers said the episode had raised questions about fairness in financial markets.
“Many Americans feel that the system is stacked against them and no matter what, Wall Street always wins,” said congresswoman Maxine Waters, who heads the House Financial Services Committee holding the hearing.
Mr Tenev said the firm, which is popular among everyday investors, was forced to temporarily limit trades due to new financial requirements imposed on the firm due to the surge in trading.
He said the firm raised new funds, which would help it avoid making similar moves in the future.
He also denied that Robinhood had been acting at the behest of anyone else.
Other business leaders called to testify at the hearing also denied wrongdoing in the affair, which saw the price of GameStop shares rise from less than $20 at the beginning of January to more than $350 in a matter of weeks.
The astonishing rise, apparently fuelled by a swarm of independent traders swapping tips online, has sparked probes examining the possibility of market manipulation.