After jumping 42% in regular session trading, Bit Digital (NASDAQ:BTBT) stock backtracks ~18% in after hours, with three trades of 999,900 each made at the close, according to the Nasdaq website. Chatter on social media focused on a short squeeze. The stock has ~27.5% short interest. Bitcoin (BTC-USD) action, up ~1% over the past day, doesn't account for the daytime surge in Bit Digital (BTBT) shares. Overall, it's a volatile stock and YTD has dropped 54%, while bitcoin's price has doubled.