Robinhood and other online trading sites are moving to curb GameStop trading and other stocks that have recently surged due to rabid transactions by smaller buyers.

As a voluntary army of buyers on social media confronted major banks who had made market bets that the price would crash, GameStop’s stock soared from below $20 earlier this month to more than $400 early Thursday. After sliding more than 30 percent in midday trading, the stock dropped, however, to about $240.

In certain cases, Robinhood said investors on Thursday would only be able to sell their positions and not open new ones, and Robinhood would aim to slow down the volume of trade with borrowed money.

Besides GameStop, Robinhood said that the new regulations would affect trade in stocks such as AMC Entertainment, Bed Bath & Beyond, Blackberry, Nokia, Express Inc., Koss Corp., American Airlines, Tootsie Roll, Trivago and Naked Brand Party.

AMC, BlackBerry, Express, GameStop and Koss option trading were all put into liquidation by Interactive Brokers, claiming unprecedented uncertainty in the markets. On “short stock positions,” it also tightened margin requirements forever.

“We do not believe that until exchanges and regulators stop or put only certain symbols into liquidation, this situation will subside,” the company tweeted.

The steps follow related trading limits by Schwab and TD Ameritrade on Wednesday.

Some major organisations, such as Citron Research and Melvin Money, have made bets that GameStop stock will plunge as the firm seeks to turn itself from a manufacturer of bricks and mortar to an online video game seller.

Smaller buyers, however, entered the stock. By taking the stock soaring higher, by purchasing the stock, they pressured the major players to cover their bets, increasing the stock even further.

The stated aim of Robinhood is to “democratise” investment and put in investment from more normal individuals. Yet the company has fallen afoul of regulators who complain that the company minimises trade risks. Robinhood says it is making steps to help warn its platform customers about such dangers.