Robinhood Markets Inc. Chief Executive Officer Vlad Tenev offered an apology for the company’s decision to temporarily curb trading in some stocks, including Gamestop Corp., on Jan. 28 amid extraordinary volatility.His apology came after House Financial Services Committee Chairwoman Maxine Waters interrupted the Robinhood CEO during his opening remarks. Her request was unusual as witnesses are allowed to make opening statements before taking questions from lawmakers. The GameStop episode, in which a group of online traders helped send shares of the video game retailer on a fierce rally earlier this year that eventually crashed, has caused worries regarding the integrity of the US stock market and the rules that govern it. The Securities and Exchange Commission and other authorities are investigating whether the saga calls for policy charges or was fueled by criminal misconduct such as market manipulation.Thursday’s hearing, which ran over five hours, is the first of three planned by the committee, Ms. Waters said. Future hearings would possibly feature representatives from the SEC and the Financial Industry Regulatory Authority.