On May 19 2021, Bitcoin suffered a double-digit percentage drop within a single session after Chinese authorities renewed warnings against crypto mining and trading, adding to a wave of deleveraging that had already been building for weeks. The move wiped out a large share of the gains from the spring rally and triggered a wave of forced liquidations across leveraged futures markets.
The session was brutal because the drop wasn't a single clean leg down — price whipsawed violently, with sharp intraday bounces that trapped buyers before rolling over again. Liquidity gaps meant stop-loss orders often filled far worse than expected, and the speed of the move left little time to react.
Same engine, same hidden right-hand side — a different day's problem.