The trading app Robinhood restricted trading yesterday on GameStop, AMC, Nokia, BlackBerry and a few other ’90s favorite brands that have been targeted for boosting by the Reddit forum WallStreetBets. It’s allowing users to buy limited quantities again today. Other brokers limited trades as well. But at least one retail investor sued Robinhood, saying the company manipulated the market to protect the hedge funds that have lost a lot of money placing short bets on GameStop over the past several months. Those funds, of course, are able to keep trading where and whenever they like. A number of Democratic lawmakers are also calling for regulation, including U.S. Rep. Ro Khanna, D-Calif., who represents Silicon Valley.