(Reuters) - Online trading platform IG Group Holdings Plc said on Saturday it will restrict any new positions on GameStop Corp and AMC Entertainment due to “extreme volatility” in the market. "Due to extreme volatility, and to prioritise the service we give our existing clients, we are not allowing any new positions to be opened on the US stocks GameStop and AMC Entertainment," London-based IG said in a tweet here. The company is the latest trading platform announcing restrictions following a surge in volumes in recent days stemming from calls on social media by individual investors to trade stocks like GameStop and AMC that were being heavily shorted by hedge funds. On Friday, the U.S. Securities and Exchange Commission waded into the battle between small investors and Wall Street hedge funds, warning brokerages and social-media traders it was on alert for any wrongdoing in this week’s roller-coaster trade.