Online broker Robinhood announced new measures that are restricting transactions for certain securities to "position-closing only" in the light of the excessive volatility Wall Street has witnessed in recent days. This means customers of Robinhood can only sell the stock if they own it, they cannot buy it. The new restrictions are sending stocks made popular by Reddit platform Wallstreetbets reeling, with some stocks cut in half.

“We continuously monitor the markets and make changes where necessary. In light of recent volatility, we are restricting transactions for certain securities to position closing only, including $AAL, $AMC, $BB, $BBY, $CTRM, $EXPR, $GME, $KOSS, $NAKD, $NOK, $SNDL, $TR, and $TRVG. We also raised margin requirements for certain securities,” the broker said in a statement.

In a similar manner, Interactive Brokers (NASDAQ: IBKR) have “put AMC, BB, EXPR, GME, and KOSS option trading into liquidation only due to the extraordinary volatility in the markets,” the broker tweeted.

“In addition, long stock positions will require 100% margin and short stock positions will require 300% margin until further notice," it was added. This means traders can't buy the stocks on margin and can't short unless they have ample liquidity.

“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,” it was further stated by Interactive Brokers.

In response to these actions, the founder of the sports and pop culture blog Barstool Sports Dave Portnoy released a series of tweets questioning Robinhood’s integrity and agenda. He called for retail investors not to close their positions.

Other leading online brokers, including E*Trade, Ameritrade, Schwab and Fidelity, are continuing to allow trading.

GameStop stock is trading down 55%, AMC is down 60%, Express (NYSE: EXPR) is down 59%, Bed Bath & Beyond (NASDAQ: BBBY) is down 39%, and BlackBerry (NYSE: BB) is down 44%, amid the Robinhood restrictions.