Impermanent Loss Definition: Impermanent loss is the difference in value between holding two tokens in a decentralised exchange liquidity pool and simply holding the same tokens in a wallet, when the relative price of the two tokens changes. The loss is “impermanent” only in the sense that it disappears if the price ratio returns to where it started — once a liquidity provider withdraws while the ratio is different, the loss is realised.
What Is Impermanent Loss?
When you deposit two tokens into an automated market maker (AMM) pool on a decentralised exchange, the protocol uses those tokens to facilitate trades for other users. In return, you earn a share of the trading fees. The catch is that the pool does not hold your tokens in a fixed ratio — it rebalances as traders swap one token for the other. If the price of the two moves apart, the pool ends up holding less of the token that appreciated and more of the one that did not.
This rebalancing has a cost. The portfolio coming out of the pool is worth less than the portfolio you would have held by keeping the same tokens in a wallet untouched. The gap is impermanent loss. It is called impermanent because if prices return to the deposit ratio before withdrawal, the gap closes. In practice prices often do not return, which is why many liquidity providers find their fee income outweighed by the loss.
Impermanent loss is a structural feature of constant-product market makers like the early versions of Uniswap, Balancer, and SushiSwap. It is not a bug or an attack — it is the price liquidity providers pay for offering automated, no-permission trading, and it is the reason fee income exists at all.
How to Calculate Impermanent Loss
The loss depends only on the ratio of price change between the two tokens — not on the absolute price level, the amount deposited, or the time elapsed. A widely-used closed-form formula gives the loss as a percentage of the value held outside the pool: at a 1.25× price change, the loss is around 0.6%; at 2× it is 5.7%; at 3× it is 13.4%; at 4× it is 20%; at 5× it is 25.5%. The loss is symmetric — a token doubling and a token halving produce the same percentage loss against simple holding.
Consider a worked example. You deposit 1 ETH and 3,000 USDC into an ETH/USDC pool when ETH is priced at $3,000, for a total deposit value of $6,000. A week later, ETH has risen to $6,000. The pool has been rebalanced by arbitrageurs throughout the week: it now contains roughly 0.707 ETH and 4,243 USDC. Withdrawing leaves you with $4,243 in stablecoins plus 0.707 ETH worth $4,243 — a total of $8,486. If you had simply held 1 ETH and 3,000 USDC, you would now have $6,000 in ETH and $3,000 in USDC, totalling $9,000. The gap of $514 — roughly 5.7% — is the impermanent loss from a 2× price change. Trading fees earned during the week offset some of this, but unless they exceed $514, the position was less profitable than holding.
Newer designs change the dynamics. Concentrated liquidity, introduced by Uniswap v3 in May 2021, lets providers commit capital only to a narrow price range. This raises fees per dollar when price stays in range, but also raises impermanent loss when it moves out of range — the provider’s whole position is then entirely in one token. Stable-asset pools paired with similar-priced tokens — implemented in smart contracts that use formulas different from the constant-product model, such as Curve’s StableSwap — reduce impermanent loss to a small fraction of what a standard pool would produce.
Impermanent Loss vs Realised Loss
| Impermanent Loss | Realised Loss | |
|---|---|---|
| State | Unrealised — visible while still in the pool | Locked in once withdrawn |
| Reversibility | Disappears if price ratio returns to deposit point | Permanent once withdrawn at a different ratio |
| Offset | Can be offset by fees if you stay in the pool | Only the net of fees minus loss matters |
| Driver | Relative price movement between paired tokens | Withdrawal at a different ratio from deposit |
Why Is Impermanent Loss Important for Traders?
Impermanent loss is the largest hidden cost of being a liquidity provider in DeFi. A pool advertising 15% annualised fee returns may produce a net negative return if the underlying tokens move sharply in opposite directions. Pools paired with liquid staking tokens against their underlying asset are an exception — those tokens trade close to a fixed ratio. Understanding the magnitude of the loss as a function of price change — 5.7% at 2×, 25.5% at 5× — turns “I’ll earn fees” into a comparison against an explicit cost.
The structural risk is that impermanent loss is permanent the moment you withdraw. There is no way to undo it, and the temptation to withdraw when a position is most underwater — for example, when one token has appreciated sharply and feels like it might reverse — is what locks the loss in. Providers who stay in pools for years often see prices oscillate enough that fees more than compensate; those who chase short-term yields and exit at unfortunate moments often lose net.
The implication for active traders is that liquidity provision is itself a directional trade. Depositing into an ETH/USDC pool is equivalent to a half-long, half-short exposure to ETH with an added short volatility position — you earn fees when prices stay stable, and lose when they move. This profile differs from simply holding either token, and choosing it well requires a view on volatility, not just direction.
Key Takeaways
- Impermanent loss is the value gap between holding two tokens in an automated-market-maker pool versus holding them in a wallet, caused by the pool’s automatic rebalancing as relative prices change.
- The loss depends only on the ratio of price change — not on absolute price, deposit size, or time elapsed — and is symmetric: a token doubling and a token halving produce the same loss.
- The loss is “impermanent” only while you stay in the pool — withdrawing at a different price ratio than you deposited at locks the loss in permanently, so timing of exit matters.
- Fees earned from the pool offset impermanent loss, but only if accumulated fees exceed the loss at the moment of withdrawal — many pools advertising attractive yields produce net losses for providers after price movement.
- Concentrated-liquidity pools amplify both fees and impermanent loss within a chosen range, while stable-asset pools designed for similarly-priced tokens minimise it.
Is impermanent loss the same as a regular trading loss?
No. A trading loss happens because you bought high and sold low; impermanent loss happens because the pool's automatic rebalancing left you holding more of the token that fell and less of the one that rose. You can experience it even when both tokens have risen in absolute price, as long as one rose much more than the other.
Can I avoid impermanent loss entirely?
Not while providing liquidity to a standard automated market maker — it is structural to the design. You can minimise it by providing liquidity only to pools of tokens expected to trade at a stable ratio (such as two stablecoins, or staked ETH against ETH), or by using newer protocol designs that hedge or absorb the loss. Holding the two tokens outside any pool avoids impermanent loss but also forfeits the fee income.
How do fees offset impermanent loss?
Every trade in the pool pays a fee distributed pro-rata to liquidity providers. If those fees accumulate faster than impermanent loss grows, the provider comes out ahead; if not, they come out behind. The break-even depends on the pool's trading volume relative to the volatility of the token pair — high-volume, low-volatility pools tend to be profitable for providers; low-volume, high-volatility pools tend to lose them money on paper-attractive yields.
