Incident All ledgers
Balancer V2: $128.0m
Balancer V2 lost $128.0m on 3 November 2025. Ranked 33rd of 1,272 crypto failures, with method, returned funds and comparable incidents.
- Date
- 3 November 2025
- Lost
- $128.0m
- Returned or repaid
- None recorded
- Target
- DeFi Protocol
- Category
- Token & Share Accounting
- Method
- Rounding Error
- Chains
- Ethereum, Arbitrum, Base, Polygon, Sonic, Optimism
Balancer V2's Composable Stable Pools lost about $128M on November 3, 2025, after an attacker abused a rounding-down error in batchSwap's invariant math, chaining many quick swaps whose tiny discrepancies drained pool reserves across multiple chains.
Against the ledger
- It ranks 33rd of the 1,272 incidents with a known loss, and 3rd in 2025.
- It accounts for 71.2% of the $179.7m in known losses in November 2025.
- 160 incidents in the ledger are classified as Token & Share Accounting, for $1.45bn in total. This one is 8.8% of that.
- The ledger records no returned funds.
Other incidents named Balancer
| Date | Target | Lost | Type | Method | Returned |
|---|---|---|---|---|---|
| 27 Aug 2023 | Balancer V2 | $800,000 | DeFi Protocol | Spot Price Manipulation | — |
| 28 Jun 2020 | Balancer | $500,000 | DeFi Protocol | Incorrect Share Accounting | — |
| 09 Sept 2026 | Balancer V1 | $250,000 | DeFi Protocol | Swap Logic Flaw | — |
| 19 Sept 2023 | Balancer V2 | $238,000 | DeFi Protocol | Frontend Compromise | — |
| 30 Aug 2026 | Balancer V1 | $234,000 | DeFi Protocol | Rounding Error | — |
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 |
| 29 Sept 2021 | Compound V2 | $147.0m | DeFi Protocol | Arithmetic Error | — |
| 30 Aug 2026 | Tectonic | $124.5m | DeFi Protocol | Donation Attack | — |
| 05 Jun 2022 | Elrond | $113.0m | DeFi Protocol | Infinite Mint | — |
All failures in 2025 · 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, “Balancer V2, failures ledger”, data to 2 November 2026, https://bitminer.io/ledger/incident/balancer-v2-2025-11-03/. How this is built