# Single-sided liquidity deposits: why adding one token can have a cost A single-sided deposit supplies one asset to a pool that represents exposure to several assets. Unlike a proportional join, it changes the pool’s balance proportions and can incur swap-like costs or fees. Supported behavior depends on the pool; receiving an LP token is different from merely storing the supplied token. Evidence: [Add/Remove Liquidity Types](https://docs.balancer.fi/concepts/vault/add-remove-liquidity-types.html); [Weighted Math](https://docs.balancer.fi/concepts/explore-available-balancer-pools/weighted-pool/weighted-math.html) Canonical: https://degreesofsatoshi.com/encyclopedia/single-sided-pool-deposits/ Published: 2026-10-02 Substantively modified: 2026-10-02 Independently verified by an automated reviewer: 2026-10-02T19:18:00.092Z Data current through: 2026-10-02 AI-assisted research and drafting with a separate automated source-verification pass; no external expert or named human review is implied. ## Key facts - **Proportional join:** Deposits follow the pool’s existing asset proportions. ([Add/Remove Liquidity Types](https://docs.balancer.fi/concepts/vault/add-remove-liquidity-types.html)) - **Single-token join:** Balancer documents a join using one token for an exact BPT output. ([Add/Remove Liquidity Types](https://docs.balancer.fi/concepts/vault/add-remove-liquidity-types.html)) - **Donation:** A donation join explicitly receives no BPT and is a different operation. ([Add/Remove Liquidity Types](https://docs.balancer.fi/concepts/vault/add-remove-liquidity-types.html)) ## Compare identical starting value Suppose an equal-value two-asset pool is balanced. Adding 50 valuation units of A and 50 of B preserves that proportion. Adding 100 of A changes it. A single-action interface can handle the second case, but the resulting LP claim is priced by the pool’s rules rather than by treating both deposits as identical. An exact LP-token-output instruction can require a variable input amount, while an exact input instruction can produce variable LP output. The labels on the quote matter. Evidence: [Add/Remove Liquidity Types](https://docs.balancer.fi/concepts/vault/add-remove-liquidity-types.html); [Weighted Math](https://docs.balancer.fi/concepts/explore-available-balancer-pools/weighted-pool/weighted-math.html) ## Read the minimum share output Inspect how many pool tokens will be minted and which fees are included. A one-token exit has the reverse distinction: receiving only one asset can differ economically from receiving the proportional basket and retaining it. Do not assume an integration called single-sided always uses Balancer’s mechanism. A wrapper may perform an external swap before joining. Evidence: [Add/Remove Liquidity Types](https://docs.balancer.fi/concepts/vault/add-remove-liquidity-types.html) ## The receipt determines subsequent exposure After the join, the holder owns a pool claim whose composition changes with trading. Starting with only A does not mean the claim will forever be redeemable for the original number of A tokens. A donation action is more different still: it adds value without minting an ownership receipt. Evidence: [Weighted Math](https://docs.balancer.fi/concepts/explore-available-balancer-pools/weighted-pool/weighted-math.html); [Add/Remove Liquidity Types](https://docs.balancer.fi/concepts/vault/add-remove-liquidity-types.html) ## Questions ### Is single-sided liquidity the same as lending one asset? No. A pool share follows AMM inventory and redemption rules. A lending claim follows a different accounting and risk arrangement. Evidence: [Add/Remove Liquidity Types](https://docs.balancer.fi/concepts/vault/add-remove-liquidity-types.html); [Weighted Math](https://docs.balancer.fi/concepts/explore-available-balancer-pools/weighted-pool/weighted-math.html) ## Claims and scope ### single-sided-pool-deposits-quick-answer A single-sided deposit supplies one asset to a pool that represents exposure to several assets. Unlike a proportional join, it changes the pool’s balance proportions and can incur swap-like costs or fees. Supported behavior depends on the pool; receiving an LP token is different from merely storing the supplied token. Scope: {"collection":"defi","dataAsOf":"2026-10-02","blockHeight":null} ### single-sided-pool-deposits-fact-proportional-join Proportional join: Deposits follow the pool’s existing asset proportions. Scope: {"collection":"defi","dataAsOf":"2026-10-02","blockHeight":null} ### single-sided-pool-deposits-fact-single-token-join Single-token join: Balancer documents a join using one token for an exact BPT output. Scope: {"collection":"defi","dataAsOf":"2026-10-02","blockHeight":null} ### single-sided-pool-deposits-fact-donation Donation: A donation join explicitly receives no BPT and is a different operation. Scope: {"collection":"defi","dataAsOf":"2026-10-02","blockHeight":null} ## Sources - [Add/Remove Liquidity Types](https://docs.balancer.fi/concepts/vault/add-remove-liquidity-types.html) — Balancer. Economics of proportional and non-proportional joins/exits. Locator: Unbalanced; Single token exact out; Proportional. Retrieved: 2026-10-02T18:53:19.923Z. - [Weighted Math](https://docs.balancer.fi/concepts/explore-available-balancer-pools/weighted-pool/weighted-math.html) — Balancer. Unequal-weight AMM invariant and spot price. Locator: Invariant; Spot price; Swap equations. Retrieved: 2026-10-02T18:53:19.859Z. ## Revision history - 2026-10-02: First publication after primary-source research and separate automated verification. ## Cite this entry Degrees of Satoshi editorial project. “Single-sided liquidity deposits: why adding one token can have a cost.” Published 2026-10-02; updated 2026-10-02. https://degreesofsatoshi.com/encyclopedia/single-sided-pool-deposits/