LibraryMarkets2019Design paperCorpus record
StableSwap — efficient mechanism for Stablecoin liquidity
Curve. Michael Egorov.
Egorov's 2019 invariant for pools of assets that should trade near parity. The curve is flat around the peg, where most stablecoin trades happen, and bends toward a constant-product tail when the pool is pushed off parity.
StableSwap shapes the curve so that similarly priced assets trade near one-to-one with low slippage, and the pool steepens into a normal product curve if the price runs away.
- Evidence
- Primary paper
- Re-measured
- No
- Assumptions
- 4
- Records linked
- 4
Code
Source, repository, and what is actually hosted
- StableSwap paperhttps://curve.fi/files/stableswap-paper.pdf
- The source URL is not a GitHub repository. No code remote is invented.
- Full text is not mirrored. Public availability is not a licence to copy the file onto this site.
- Add to a reading list
01 Claim ledger
What the paper is allowed to say
Each row is a sentence already in the study. The status is the same on every row: a model claim, not a live measurement.
Claim 01 · Paper model
Constant product is wasteful for stablecoins
A dollar-for-dollar pair does not need liquidity at a price of ten. The paper concentrates the curve around one.
Claim 02 · Paper model
The amplification parameter is the shape
A higher A makes the pool flatter near the peg and more violent away from it. A is the product decision. It is not a minor constant.
Claim 03 · Paper model
The invariant blends two curves
Near equality, the pool behaves like a constant sum, which has no slippage and no rebalancing force. Far away, it behaves like a constant product, so it cannot be drained of one asset for nothing.
Claim 04 · Paper model
The peg is an assumption the pool does not create
The mathematics serves assets that ought to be worth the same. If one of them breaks, the pool will sell the good asset for the bad one all the way along that flat region.
Claim 05 · Paper model
Liquidity providers are betting on the peg
They earn fees from tight spreads and they warehouse the asset that loses the peg. The paper's efficiency and this warehouse risk are the same design.
02 Three cuts
Observation, model, falsifier
A desk does not stop at the summary. Each claim is cut three ways, using only this study's own assumptions and checks. Nothing here is a new figure.
01 Constant product is wasteful for stablecoins
Observation
What the study says
A dollar-for-dollar pair does not need liquidity at a price of ten. The paper concentrates the curve around one.
Model
What has to hold
The assets are meant to track the same value most of the time. The curve is a bad fit for uncorrelated coins.
Falsifier
What would retire it
Is the internal price being used as proof that a token is worth a dollar?
02 The amplification parameter is the shape
Observation
What the study says
A higher A makes the pool flatter near the peg and more violent away from it. A is the product decision. It is not a minor constant.
Model
What has to hold
Arbitrage against a redemption market exists. Without it the internal price is only a ratio of inventory.
Falsifier
What would retire it
Is there a redemption market outside the pool for each asset?
03 The invariant blends two curves
Observation
What the study says
Near equality, the pool behaves like a constant sum, which has no slippage and no rebalancing force. Far away, it behaves like a constant product, so it cannot be drained of one asset for nothing.
Model
What has to hold
A is set by someone whose incentives a provider understands.
Falsifier
What would retire it
Is there a redemption market outside the pool for each asset?
04 The peg is an assumption the pool does not create
Observation
What the study says
The mathematics serves assets that ought to be worth the same. If one of them breaks, the pool will sell the good asset for the bad one all the way along that flat region.
Model
What has to hold
The assets are meant to track the same value most of the time. The curve is a bad fit for uncorrelated coins.
Falsifier
What would retire it
Is there a redemption market outside the pool for each asset?
05 Liquidity providers are betting on the peg
Observation
What the study says
They earn fees from tight spreads and they warehouse the asset that loses the peg. The paper's efficiency and this warehouse risk are the same design.
Model
What has to hold
The assets are meant to track the same value most of the time. The curve is a bad fit for uncorrelated coins.
Falsifier
What would retire it
Is there a redemption market outside the pool for each asset?
03 Sequence
One action, as an operating tape
- 01Providers deposit the stable assets in whatever shares the pool allows and receive pool tokens.
- 02A trader swapping one dollar token for another moves along the flat part of the curve and pays a small fee, while A is large and balances are close.
- 03If one asset's external price falls and traders keep selling it into the pool, balances tilt.
- 04As the tilt grows, the invariant steepens. Further sales move the internal price more, which is the pool's way of stopping a complete drain.
- 05Providers who withdraw during the tilt receive more of the impaired asset. The fee income is what they hoped would pay for that.
04 Load-bearing
The argument, and where a pitch drops it
Flat means generous, which means exposed
The cut
The reason a stable swap is cheap is that the pool does not defend a price of one with slippage. Defence has been turned down on purpose. Anyone citing the tight spread should cite the depeg loss in the same sentence.
Why it carries weight
If this cut is skipped, the paper's name is being used without the mechanism that makes the name mean anything.
Where it is dropped
A later client, parameter or reward formula is a different object from this paragraph.
A is a governance surface
The cut
Raising A makes trading nicer and makes a depeg more expensive for providers. Who may change A, and how fast, is part of the risk. The paper introduces the parameter. Deployments decide who turns the dial.
Why it carries weight
If this cut is skipped, the paper's name is being used without the mechanism that makes the name mean anything.
Where it is dropped
The paper is not a claim about any stablecoin's reserves.
The pool is not an oracle of the peg
The cut
A flat internal price says the pool is balanced, or that A is high, not that each token can be redeemed for a dollar in a bank. External redemption is outside the invariant.
Why it carries weight
If this cut is skipped, the paper's name is being used without the mechanism that makes the name mean anything.
Where it is dropped
A later client, parameter or reward formula is a different object from this paragraph.
05 Register
What has to be true
Model · Not re-measured
The assets are meant to track the same value most of the time. The curve is a bad fit for uncorrelated coins.
Model · Not re-measured
Arbitrage against a redemption market exists. Without it the internal price is only a ratio of inventory.
Model · Not re-measured
A is set by someone whose incentives a provider understands.
Network · Not re-measured
Tokens do not rebase or charge hidden transfer fees that desynchronise the balances.
06 Divergence
What happened after the paper
Curve deployed StableSwap for dollar stablecoins and later generalised it. Several depegs showed the warehouse risk in public, including events where the pool became a large holder of the impaired asset. The paper's math did what it said. The losses came from the peg assumption failing, which the design does not prevent.
A later client, parameter set, or reward formula is a different object. Cite this paper for the mechanism. Cite a primary release for the network. This desk has not re-run the proof.
07 Pre-mortem
What to check before you use the idea
- 0 of 4 marked on this browser. A mark is a reading note, not a pass, a rating, or a recommendation.
08 Anatomy
The paper, in the order a builder needs
The problem it names
A constant-product pool of two stablecoins quotes a meaningful spread even when both claim to be worth the same unit. That spread is a tax on the common case. A constant-sum pool quotes no spread and then goes bankrupt in inventory the moment the peg slips.
What the design proposes
- An amplification parameter blends a constant-sum region with a constant-product tail.
- The pool is for assets that share a unit of account, not for unrelated volatile pairs.
- The invariant is explicit. Changing the amplification changes the risk, and the paper treats it as a parameter with consequences.
How the mechanism is specified
What this page does not treat as proven
- The math assumes the assets ought to be near parity. If that assumption is false, the flat region is a source of loss, not efficiency.
- Amplification is a risk setting. Higher is not 'better'.
- The paper is not a claim about any stablecoin's reserves.
Why the desk still reads it
This is the first document we ask for when a venture designs a pool of assets 'that should be worth the same'. If they cannot say what happens when the assets stop being worth the same, they have not finished the design.
09 Lexicon
Terms, opened into the record
- Amplification
- The parameter A. Higher means a flatter curve near equal balances.
- Stable invariant
- A blend of constant-sum and constant-product so pegged assets trade tightly until they diverge.
- Depeg
- One asset leaving the shared price. The pool then accumulates it, because that is where the flat curve is generous.
- Warehouse risk
- The provider's exposure to ending up holding more of the asset that failed.
10 Repository
Every linked record on this page
Underlined words open a page that already exists: a concept, a protocol profile, a failure record, or another paper. If a word is not underlined, this desk does not have a record for it.
Concepts
Papers
This is Blockchain Lab's reading of a public design paper. It is not the paper, not a copy of it, and not an offer of tokens, equity, custody or a partnership. Later network behaviour can diverge from the text. Nothing here is investment, legal or technical advice.
Research status: Design paper. Last reviewed: 1 October 2026. This is a reading of a public paper, not investment, legal or security advice.
