Interactive Brokers and Robinhood raise margin requirements for trading in GameStop

Two large online trading platforms moved to limit trading in shares of GameStop and other companies that had been caught up in the recent 'melt-up' in their share prices.

By raising margin requirements for trading in those securities they were implicitly also protecting themselves.

In remarks to CNBC, Interactive Brokers said that as of midday on 27 January, it had put trading in options on AMC Entertainment, Blackberry, Express, GameStop and Koss Corp."into liquidation only due to the extraordinary volatility in the markets."

Interactive also raised margin requirements on long stock positions to 100% and that for short positions to 300% "until further notice".

"We do not believe this situation will subside until the exchanges and regulators halt or put certain symbols into liquidation only. We will continue to monitor market conditions and may add or remove symbols as may be warranted," the broker added.

For its part, Robinhood said it too had moved to restrict transactions for the above securities, as well as for Bed,Bath and Beyond, Naked Group, and Nokia, among others.

Robinhood also raised margin requirements for certain securities.