Blockchain/Level VII · Evolution/7.3 Booms, busts and institutions/Lesson 2
Exchange failures: Mt. Gox to FTX
The pattern of custodial failure: from missing keys to commingled funds
MaterialsA block explorerThe FTX bankruptcy filings (public record)A notebook to track each failure’s timeline
Wonder
- What is the difference between holding an asset and holding a claim to it?
- Why do exchange failures recur despite the underlying technology remaining secure?
- How does a single firm’s insolvency trigger a cascade of defaults across its affiliates?
Explore
- Mt. Gox halted withdrawals in February 2014, citing transaction malleability, a technical issue where transaction IDs change after broadcast. The exchange filed for bankruptcy shortly after, reporting that about 850,000 BTC were missing; about 200,000 were later found, leaving a loss of roughly 650,000. The event highlighted the distinction between ownership and custody: users held claims against the exchange, not direct control of the coins on the blockchain.
- Bitfinex suffered a different failure mode in August 2016 when an attacker stole roughly 120,000 BTC from customer wallets. In 2022, US authorities arrested two individuals in New York and recovered most of the stolen coins through complex tracing efforts. This case demonstrated that while private key management is critical for exchanges, forensic blockchain analysis can sometimes recover assets lost to theft, though not necessarily in time for creditors.
- QuadrigaCX collapsed in 2019 after its founder, Gerald Cotten, died in India in December 2018. The company said customer funds sat in cold storage that only Cotten could access, but Ontario regulators later found that most of the money had already been lost to his fraud and trading. Sole control made the deception easy to hide.
- Celsius Network froze withdrawals in June 2022 as its lending book became insolvent due to market downturns and credit defaults from borrowers like Three Arrows Capital. Unlike an exchange, Celsius operated as a lender, promising yields on deposited crypto assets. When the underlying loans went bad, the firm lacked sufficient liquid reserves to honor redemption requests, illustrating how leverage amplifies risk in custodial platforms.
- FTX’s collapse began on 2 November 2022 when CoinDesk reported that Alameda Research, its sister trading firm, held much of its balance sheet in FTT, FTX’s own token. Binance announced it would sell its FTT holdings, triggering a run. FTX halted withdrawals within days and filed for bankruptcy on 11 November 2022, with billions in customer funds missing due to commingling between the exchange and Alameda.
- Sam Bankman-Fried was convicted on seven counts of fraud and conspiracy in November 2023 and sentenced to 25 years in prison in March 2024. The FTX case revealed that customer deposits were treated as free float for corporate spending rather than held in segregated reserves. In response, major exchanges began publishing ‘proof of reserves’ using cryptographic techniques to verify their solvency publicly.
Key facts
- Mt. Gox reported about 850,000 BTC missing in February 2014; about 200,000 were later found.
- Bitfinex was hacked in August 2016, losing about 120,000 BTC; most were recovered by US authorities in 2022.
- QuadrigaCX collapsed in 2019 after its founder’s death; regulators found the funds had largely been lost to his fraud.
- Celsius froze withdrawals in June 2022 due to insolvency from bad loans.
- FTX filed for bankruptcy on 11 November 2022 with billions in customer funds missing; Sam Bankman-Fried was sentenced to 25 years in March 2024.
- Recurring threads include weak security, commingled customer funds and the absence of verifiable reserves.
Exercise nine, six, three, one
9CollectList 9 major exchange or custodian failures from 2013 to 2025. Note the date, the amount lost (if known), and whether the cause was theft, mismanagement, or insolvency.
6ClusterGroup the 9 failures into 6 categories based on the root cause: key loss, external hack, internal fraud, market-driven insolvency, regulatory shutdown, or operational error.
3DistillReduce the 6 categories to 3 fundamental reasons why custodial platforms fail despite holding private keys for millions of users.
1CrystallizeWrite 1 sentence on what ‘proof of reserves’ technically verifies and what it cannot prove about a firm’s future solvency.
Fact check
Dates, figures and claims checked against the published sources listed below.