The video game retailer GameStop’s stock saw more extreme volatility Thursday after the popular trading app Robinhood restricted transactions for it and other hot stocks whose values were boosted by a mob of online traders. Furious Robinhood users said they were unable to transfer funds to their bank accounts or to other trading platforms, but experts say it’s in their best interest. Some amateur traders made their purchases on margin — a risky move that could magnify their losses. “It helps protect people from themselves — those who are late to the party and will get stuck holding the bag when this mania comes to a likely sudden and inglorious end,” one financial analyst said. | 