Incident All ledgers
Compound V2: $147.0m
Compound V2 lost $147.0m on 29 September 2021. Ranked 29th of 1,272 crypto failures, with method, returned funds and comparable incidents.
- Date
- 29 September 2021
- Lost
- $147.0m
- Returned or repaid
- None recorded
- Target
- DeFi Protocol
- Category
- Token & Share Accounting
- Method
- Arithmetic Error
- Chains
- Ethereum
A comparison-operator error in Compound V2's Comptroller, triggered when Proposal 62 went live on September 29-30, 2021, let users claim excess COMP tokens. The record puts the figure at $147 million.
Against the ledger
- It ranks 29th of the 1,272 incidents with a known loss, and 3rd in 2021.
- It accounts for 75.1% of the $195.9m in known losses in September 2021.
- 160 incidents in the ledger are classified as Token & Share Accounting, for $1.45bn in total. This one is 10.1% of that.
- The ledger records no returned funds.
Closest in size by the same method
| Date | Target | Lost | Type | Method | Returned |
|---|---|---|---|---|---|
| 22 May 2025 | Cetus CLMM | $223.0m | DeFi Protocol | Arithmetic Error | — |
| 13 Mar 2023 | Euler V1 | $197.0m | DeFi Protocol | Donation Attack | $240.0m |
| 03 Nov 2025 | Balancer V2 | $128.0m | DeFi Protocol | Rounding Error | — |
| 30 Aug 2026 | Tectonic | $124.5m | DeFi Protocol | Donation Attack | — |
| 05 Jun 2022 | Elrond | $113.0m | DeFi Protocol | Infinite Mint | — |
All failures in 2021 · The failures ledger
Amounts are DefiLlama’s estimates and can change as incidents are revalued. Its returned figure can include money a company repaid itself, not only funds recovered from attackers. Source: DefiLlama.
Cite this Bitminer.io, “Compound V2, failures ledger”, data to 2 November 2026, https://bitminer.io/ledger/incident/compound-v2-2021-09-29/. How this is built