The Complete Guide to Balancer

可编程流动性

Pools can be created with custom token weights, swap fees and logic. Developers can build new AMM curves and, in v3, attach hooks to existing pool types.

投资组合管理器

每当资金池偏离其目标权重时，套利者就会对其进行交易。流动性提供者（LP）从这些交易中赚取费用，而不是为再平衡付费。.

资本高效

智能订单路由将交易拆分到多个资金池以寻找更优价格。金库仅结算多跳交换的净代币转移，从而节省 gas。.

The November 3, 2025 Exploit

On November 3, 2025, from 7:46 AM UTC, an attacker drained Balancer V2 Composable Stable Pools on several networks. Per Balancer's post-mortem (November 18, 2025), the exploit relied on incorrect rounding in the "exact out" swap path of stable pools: the required input amount was rounded down, so the caller underpaid. It needed three conditions at once: that rounding error, rate providers that added imprecision to the math, and a pool pushed into a very low liquidity state, which Composable Stable Pools allowed because their own pool token could be swapped in a batch. The post-mortem estimates the theft of user funds at $95 million; a December 2025 Balancer post puts the amount drained at $121 million.

Whitehats acting under the SEAL Safe Harbor Agreement recovered about $8 million, and StakeWise handled another $20 million in osETH and osGNO separately, per BIP-892. Newer V6 Composable Stable Pools were still inside their pause window and were paused within minutes. Balancer V3, every V2 weighted pool and the other V2 stable pool types were not affected, per the post-mortem. Independent analyses were published by Certora and Trail of Bits.

What Changed After the Exploit

• BIP-887 made V3 the only Balancer platform for new liquidity and disabled the V2 pool factories that could be disabled. Existing V2 pools still run, but Balancer encourages LPs to migrate.
• In March 2026, co-founder Fernando Martinelli announced the wind-down of Balancer Labs, citing the legal exposure created by the exploit. The protocol continues through the DAO, the Balancer Foundation and service providers.
• BIP-919 (BAL Tokenomics Revamp) passed on Snapshot in April 2026 with about 2.09 million votes for and 1.75 million against. It halted BAL emissions, discontinued veBAL, sent 100% of protocol fees to the DAO treasury and cut the protocol's share of V3 swap fees from 50% to 25%.
• On August 31, 2026, a rounding bug in legacy V1 pools (immutable 2020 code with no pause function) was exploited for about $1 million, per BIP-930.

The original pool type. Each token has a weight (for example 80/20 or 60/20/20) that sets its share of the pool's value. The pool's invariant keeps the weighted product of the token balances constant.

80/20 ETH/USDC 资金池旨在将其价值的 80% 保持在 ETH 中，20% 保持在 USDC 中。随着市场价格变动，套利者会与资金池进行交易，直到其恢复到这些权重，而 LP 在每笔交易中赚取兑换费。.

SOR 会查询 Balancer 资金池，为交易寻找最佳路径。对于大额兑换，它可以将订单拆分到多个资金池，以减少价格影响。交易者获得更好的价格，更多资金池也能获得交易量。.

Aggregators such as 1inch, ParaSwap and CoW Swap can also route trades through Balancer pools when they offer the best price, so pools receive volume from users who never open the Balancer app.

Vault 于 2021 年在 Balancer v2 中引入，是一个单一合约，负责持有并记录每个 Balancer 池的代币。池合约仅包含定价逻辑。根据 Balancer 文档，这种拆分正是使其余设计成为可能的关键。.

通过 Vault 进行的多跳交换仅在交易结束时转移净差额，从而降低 gas 成本。Vault 还提供闪电贷：在同一笔交易内借入并偿还的代币。.

Batch swaps run several swaps in one transaction and settle only the net token transfers. This makes routes with many hops cheaper than running each hop separately.

Flash loans let arbitrageurs borrow tokens from the Vault for the length of one transaction, use them to close a price gap between pools, and repay them before the transaction ends. This keeps pool prices close to the wider market. The same batch mechanism, combined with the rounding error, is what the November 2025 attacker used against Composable Stable Pools, per the post-mortem.

加权池

The most general pool type, with up to eight tokens at custom weights, per the Balancer docs. It suits index-style portfolios that earn trading fees. A common setup is an 80/20 pool that pairs a protocol's governance token with ETH; Balancer's own 80 BAL / 20 WETH pool was still its largest on November 10, 2026, with $4 million in TVL, per DefiLlama.

稳定池

Built for tokens that trade near a 1:1 ratio, such as stablecoins (USDC, DAI, USDT) or liquid staking tokens against ETH (wstETH/WETH). Stable pools use a StableMath curve that keeps the price tight around the peg, so swaps between similar assets see less slippage. In v2 the composable variant, the Composable Stable Pool, is the type exploited in November 2025; V3 stable pools use a different codebase.

线性池（v2，已弃用）

一种 v2 池类型，使用线性定价曲线将基础代币（例如 DAI）与其生息包装代币（例如来自 Aave 的 aDAI）配对。线性池是 v2 增强池的构建模块。根据 Balancer 论坛，在 2023 年 8 月披露漏洞后，Balancer 已弃用它们。v3 用流动性缓冲区取代了它们。.

提升池

Boosted pools send liquidity that is not needed for swaps to a lending market such as Aave, so LPs earn both swap fees and lending interest. In v3, a 100% boosted pool holds its whole balance in yield-bearing tokens (ERC-4626 vault shares), and a buffer of the underlying token handles swaps, per the Balancer v3 docs.

如何提供流动性

了解暂时性损失

Impermanent loss (IL) is the gap between the value of your pool share and the value of simply holding the same tokens, when their prices move apart after you deposit. The larger the move, the larger the gap. Pool weights change how much IL you take (our impermanent loss guide works through more examples):

BAL 代币经济学

veBAL System (Discontinued in 2026)

Until 2026, users obtained veBAL by providing liquidity to the 80/20 BAL/WETH pool and locking the resulting BPT for up to one year. A longer lock gave more veBAL, which decayed as the lock ran down. BIP-919 discontinued it: veBAL no longer earns fees or directs emissions, holders received a one-off payment of 500,000 USDC (BIP-920), and a buyback offer at net asset value, capped at 35% of the treasury, gave holders an exit, per the Balancer docs.

What Happened to Gauge Votes and Aura

As with Curve, a market for gauge votes had grown around Balancer: protocols paid veBAL holders, through platforms such as Hidden Hand, to vote emissions to their pools, and Aura Finance pooled veBAL on behalf of depositors. BIP-919 argued that this incentive market cost more in emissions than the fees it generated. With emissions and veBAL gone, that model no longer applies; check the Aura documentation for how Aura works today (see Sources).

兑换费用

The base layer. Every trade through your pool pays a swap fee that stays in the pool, so the value of your BPT rises. Each pool sets its own fee within the range its pool type allows (in v3, 0.001% to 10% for weighted pools and 0.0001% to 10% for stable pools, per the Balancer docs). Nothing needs to be claimed. With $69 million of volume over 30 days across all of Balancer, fee income per dollar is modest.

BAL Emissions (Halted in 2026)

Until April 2026, LPs could stake BPT in a pool's gauge to earn weekly BAL rewards directed by veBAL votes. BIP-919 set the weight of every gauge type to zero, so new BAL rewards stopped. Any incentives still shown on a pool come from partner protocols, in their own tokens.

提升池收益

In a boosted pool, liquidity not needed for swaps sits in a lending market such as Aave or Morpho and earns interest. That interest comes on top of swap fees, so one deposit earns from two sources, and it also carries the risk of the lending market.

可组合性 & 高级策略

BPT is a standard ERC-20 token, so it can be used in other protocols. Some common patterns, each with its own extra risk:

当代币价格偏离您存入时的比例时，您的池份额价值会低于直接持有这些代币。如果您以该新比例提取，损失将变为永久性的。波动性交易对带来的无常损失最大。相关性交易对（稳定币、LST/ETH）以及偏向您偏好资产的加权池可以减少无常损失。.

Balancer's contracts have been audited by firms including Trail of Bits, OpenZeppelin and Certora (reports are in the GitHub repositories, see Sources), and the protocol runs a bug bounty. Audits did not prevent three incidents: in August 2023 a flaw in some v2 boosted pools was exploited; on November 3, 2025 a rounding flaw in v2 Composable Stable Pools led to an estimated $95 million theft; and on August 31, 2026 a bug in legacy V1 pools, which cannot be paused, was exploited for about $1 million. Check which pool version you use, avoid legacy V1 and V2 pools, and read the latest security notices on the forum.

Pool creation is permissionless: anyone can create a pool. Some pools hold tokens with malicious contracts, rebasing supply or fee-on-transfer logic that behave badly inside the Vault. Verify each token contract in a pool before you deposit. Small pools are also thin: with total TVL at $31 million, many pools hold only a few million dollars or less, so large deposits and withdrawals move the price.

Balancer Labs, the company that built the protocol, announced its wind-down in March 2026; development and operations now depend on the DAO, the Balancer Foundation and service providers funded by protocol fees. BIP-919 passed with a narrow majority (about 2.09 million votes against 1.75 million), so further changes to fees and governance are possible. Lower volume means lower fee income for LPs, and liquidity that leaves a pool widens its spreads.