Curriculum·S201 Market Structure and Price Formation·about 41 min
Order books
By the end of this lesson you can
- →Read a book as inventory at prices rather than as a price, and estimate the fill of a given size
- →Explain why displayed depth is an offer that can be withdrawn, not a commitment
- →Compute the notional required to move a book by a stated percentage, and invert it to size a position
- →Identify the conditions under which depth disappears precisely when it is needed
Sophomore · enrolled learners
This lesson opens with The liquidation cascade of 10 October 2025.
- What happened
- Following President Trump's announcement of a 100 percent tariff on Chinese imports, crypto markets sold off into perpetual futures open interest of about $217B, near a record, by CoinDesk's figures. More than $19B of leveraged positions were liquidated within 24 hours by Coinglass data, the largest single-day liquidation event on record. Of the $9.89B in forced liquidations Amberdata counted over the 14-hour cascade, about 70 percent occurred inside 40 minutes, at a rate it reported as 14.6 times the hours before and after, with a peak minute of $3.21B of which 93.5 percent was forced selling. CoinGecko counted more than 1.6 million trading accounts liquidated. By CoinGecko's count bitcoin fell 14.5 percent to $104,782 and ether 12.2 percent to $3,436. Market makers withdrew bids, widened their spreads or stepped away altogether during the event, draining the books further.
- The decision point
- Every position that liquidated had been sized against depth that was visible on a screen beforehand. That depth was an offer, not a commitment, and the parties posting it are under no obligation to keep it there. The books were thinnest at the exact moment the largest volume needed to cross them, because the same conditions that produce forced selling also cause market makers to step away.
- Recorded loss
- $19,000,000,000
What you will be able to answer
- →What is an order book?
- →Is displayed depth a commitment?
- →What did 10 October 2025 demonstrate about depth?
- →How do you size a position against a book?
Orientation and Year One are open: anyone can read them without an account. From Year Two onward the lessons are for enrolled learners, because progress through the later years only means anything if it is tracked against a record.
It is free. We do not sell the list and there is nothing to buy at the end of it.
Sources and review
- https://www.coindesk.com/research/market-spotlight-the-19-billion-liquidation-that-shook-crypto
- https://www.coingecko.com/learn/october-10-crypto-crash-explained
- https://www.fticonsulting.com/insights/articles/crypto-crash-october-2025-leverage-met-liquidity
- https://www.sec.gov/newsroom/press-releases/2023-13
- https://www.kaiko.com/resources/how-3-21b-vanished-in-60-seconds-october-2025-crypto-crash-explained-through-7-charts
- https://www.soliduslabs.com/post/mango-hack
- https://www.cftc.gov/PressRoom/PressReleases/8647-23
Confidence high·Volatility medium·Reviewed 2026-10-22·Owner unassigned
Contested
Liquidation totals for 10 October 2025 vary between roughly $19B and higher figures depending on the venues counted and on how exchanges report partial liquidations. The $19B is Coinglass data as reported by CoinDesk and CoinGecko. It is often argued that reported figures understate reality because some venues report liquidations through throttled feeds; we have not verified that venue by venue, so treat $19B as a reported figure with its source attached rather than a measured total.
The tariff announcement is the widely reported trigger, and a trigger is not a cause. The condition that made a cascade possible was record open interest against finite depth, which would have been true of any sufficiently large shock. Do not let a revision present the news event as the explanation.
The shape figures ($9.89B over 14 hours, 70 percent in 40 minutes, a rate 14.6 times the hours either side, a $3.21B peak minute that was 93.5 percent forced selling) are Amberdata's, republished by Kaiko after it acquired Amberdata; they count a narrower set of venues than the $19B total. Price lows differ by source and by time: CoinGecko gives bitcoin at $104,782 and ether at $3,436, CoinDesk gives $106,560 and $3,551. The 1.6 million accounts figure is CoinGecko's.
The Mango Markets figures repeated here, about $4M of buying moving the oracle-reported price by 2,300 percent, are Solidus Labs' (18 October 2022). The CFTC describes the same move as the oracle price jumping over 13-fold in a 30-minute span and puts the withdrawal at over $110M; the SEC and Solidus Labs give about $116M.