Retail investors, egged on by Reddit thread WallStreetBets, have sent shares of heavily shorted companies such as GameStop Corp and AMC Entertainment through the roof, leading to what is called as a short squeeze that has forced a handful of brokerages to book heavy losses. Robinhood, which has been at the heart of the historic trading frenzy, drew investor ire after it was forced to curb trading in certain hot stocks due to a 10-fold rise in deposit requirements at its clearinghouse. "The clearinghouse deposit requirements are designed to mitigate risk, but last week's wild market activity showed that these requirements, coupled with an unnecessarily long settlement cycle, can have unintended consequences that introduce new risks," Tenev said.