“As volatility increased, the DTCC (Depository Trust & Clearing Corporation) increased the deposit requirements for brokers.”
Trades take two days to settle, and the clearinghouse wants collateral against the risk in the meantime. Buys in a volatile stock raised what Robinhood had to post. Sells lowered it. The answer is a cash-strapped broker, not a hedge fund phone call, and that is still Robinhood’s fault for not raising enough capital.