Flash Crash
In simple terms
A flash crash is when a cryptocurrency's price suddenly drops very fast, then bounces back up just as quickly—like a stock market hiccup. It usually happens when there aren't enough buyers and sellers in the market, or when someone places a huge order that temporarily overwhelms the market.
Definition
A sudden, extreme price drop that recovers quickly, often caused by low liquidity or large orders.
In depth
A flash crash occurs when extreme selling pressure—often from large market orders, liquidation cascades, or low liquidity conditions—causes the price of an asset to plummet within seconds or milliseconds before recovering. These events are amplified in decentralized exchanges or low-volume trading pairs where the order book depth is insufficient to absorb large trades smoothly. Flash crashes can be triggered by automated trading algorithms, margin calls, or sudden withdrawals of liquidity from AMMs (automated market makers), and they often impact derivative markets where leveraged positions trigger liquidation events that feed back into spot prices.
How does Flash Crash work?
An order book holds only a finite amount of resting buy interest at each price. When an unusually large market sell, a stop-loss chain, or a wave of liquidations arrives, it consumes the nearest bids and keeps walking down to progressively worse prices. Automated market makers detect the abnormal move and pull their quotes, removing the depth that would normally cushion it, so the drop accelerates. Within seconds the venue's price can sit far below other exchanges. Arbitrageurs and resting buyers then refill the book, and quotes usually recover, though every trade printed during the gap stands.
An example
Illustratively, a coin quoted near $200 has only about $2 million of bids within five percent of that price. A $10 million market sell arrives at a quiet hour, clears those bids, and prints trades down to $150 within about twenty seconds before recovering to $196 a few minutes later. A trader whose stop-loss was set at $180 was triggered into the gap and filled near $158, a realized loss the recovery does not undo.
Figures are illustrative only.
What beginners get wrong
- A market stop-loss becomes a market order once triggered, so during a flash crash it can fill dozens of percent below the stop price.
- Charts from a single exchange can show a wick that no other venue printed; comparing several venues shows whether the move was market-wide.
- Some venues cancel clearly erroneous trades after a crash and others do not, so an executed fill may or may not stand.
- Assuming a fast recovery is a mistake: some flash crashes on thin pairs never return to the prior level.
Related terms
Part of
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Educational only — not financial advice.