Impermanent Loss Explained

Impermanent loss is the gap between what your tokens are worth inside a liquidity pool and what they would have been worth if you had simply held them in your wallet. It happens because an automated market maker constantly rebalances your deposit — selling the token that rises, accumulating the one that falls — so you always end up with less of the winner. It is the single most underestimated cost of providing liquidity, and you should be able to compute it before you deposit a dollar.

Why the Pool Rebalances You

Recall how a constant product AMM works: a pool holds two tokens, and every trade must keep the product of the reserves constant. When one token's market price rises, arbitrage traders buy it from the pool — which is briefly selling it too cheaply — until the pool's implied price matches the market again.

Those arbitrage trades are executed against your deposit. Every time the pool's price catches up to the market, liquidity providers have sold some of the appreciating token below its new price and bought more of the other one. The pool cannot help this; the formula is doing exactly what it was designed to do. But the result is that an LP position is structurally short volatility: any large price move in either direction leaves you worse off than holding.

The word "impermanent" reflects one narrow truth: if prices return exactly to their ratio at the time you deposited, the loss vanishes. That framing has misled a lot of people. Prices are under no obligation to return, and the moment you withdraw, the loss is locked in and entirely permanent. A more honest name, used in research literature, is divergence loss — the loss grows with how far the two assets' prices diverge from their starting ratio.

A Worked Example with Real Numbers

Suppose ETH trades at $3,000 and you deposit into a 50/50 ETH/USDC pool: 1 ETH plus 3,000 USDC, a $6,000 position. For simplicity, imagine your deposit is the whole pool.

ETH doubles to $6,000. Arbitrage rebalances the pool until its price matches. Under the constant product rule, your position becomes approximately 0.707 ETH and 4,243 USDC.

• Value in the pool: 0.707 × $6,000 + $4,243 ≈ $8,485
• Value if you had just held: 1 ETH × $6,000 + $3,000 = $9,000
• Impermanent loss: about $515, or 5.7% of the hold value.

You still made money — $8,485 is well above your $6,000 entry — which is exactly why the loss goes unnoticed. You gained 41% while the plain holder gained 50%. The pool quietly sold your ETH on the way up.

The loss depends only on the price ratio change, in either direction. For a two-asset 50/50 constant product pool:

Price ratio change	Loss vs holding
1.1x	0.1%
1.25x	0.6%
1.5x	2.0%
2x	5.7%
3x	13.4%
4x	20.0%
5x	25.5%

Note the shape: small moves are nearly free, but the loss accelerates. A stablecoin depegging or a token going on a 5x run inflicts serious damage. And "ratio" is what matters — if both tokens double together, the ratio is unchanged and there is no divergence loss at all.

Fees Are the Other Side of the Ledger

Nobody provides liquidity for fun; they do it because every swap pays a fee into the pool. Your true return as an LP is:

LP return = fees earned + price change of holdings − divergence loss

The economics hinge on the ratio of trading volume to pool size. A pool that turns over its entire liquidity every day at a 0.3% fee generates roughly 0.3% daily for LPs — over 100% annualized before losses — and can absorb substantial divergence. A pool that trades 2% of its liquidity per day generates about 2% annually in fees, which a single 1.5x price move would wipe out.

Some realistic patterns:

• Stablecoin pairs (USDC/USDT) have almost no divergence risk because the prices track each other. Fees are tiny per trade, but nearly all of them are kept. Returns are modest and relatively predictable — with the caveat that a depeg converts "almost no risk" into severe loss, because the pool dumps the good stablecoin and fills you with the broken one.
• Correlated pairs (ETH and a liquid staking token) also diverge little in normal conditions, making fee income mostly keepable.
• Volatile pairs (ETH/USDC, or a new token against ETH) can earn high fees but suffer the full force of divergence. LPs in pools for newly launched tokens often lose badly: if the token collapses, the pool automatically buys it all the way down and hands you a bag of it.

Studies of major AMM pools have repeatedly found that a large share of LPs — in some analyses, roughly half or more in volatile pools — would have done better simply holding. Treat fee APYs shown on interfaces as gross figures that ignore your largest cost.

Concentrated Liquidity Raises the Stakes

Modern AMMs like Uniswap v3 let you concentrate liquidity into a chosen price range — say $2,800 to $3,300 for ETH/USDC. Within that range your capital behaves like a much larger full-range position, multiplying your fee share, sometimes by 10x or more.

Divergence loss is multiplied by the same logic. Your position converts entirely into the weaker asset by the time price exits your range, and then earns nothing until price returns or you rebalance. Concentrated LPing is closer to actively market-making than to passive yield: it demands monitoring, rebalancing (each rebalance realizes losses and costs gas), and a view on where price will stay. Beginners should treat narrow ranges as an advanced tool, not a bonus multiplier.

Before You Provide Liquidity

A short checklist that filters out most bad LP decisions:

1. Run the divergence math first. Ask: if one asset moves 2x against the other, am I comfortable with a 5.7% haircut versus holding? For the pairs I'm considering, how likely is that move over my intended holding period?
2. Check volume-to-liquidity, not the advertised APY. Fees are the only sustainable income; look at whether daily volume is a meaningful fraction of pool size, and whether the APY shown includes temporary token reward subsidies.
3. Prefer correlated or stable pairs while learning. They keep the fee income while minimizing the divergence term — accepting the tail risk of a depeg.
4. Know that you cannot exit instantly into what you deposited. You withdraw whatever mix the pool currently holds, at current prices, not the tokens you put in.
5. Size it as a strategy, not a savings account. Providing liquidity is an active position with a specific risk profile — not "parking" tokens.

Key Takeaways

• Impermanent loss (better: divergence loss) is the shortfall of an LP position versus simply holding, caused by the AMM automatically selling whichever asset rises.
• It depends only on how far the price ratio moves: about 0.6% at 1.25x, 5.7% at 2x, and 20% at 4x for a standard 50/50 pool — in either direction.
• The loss becomes fully permanent the moment you withdraw; prices have no obligation to return to your entry ratio.
• Your real return is fees minus divergence loss; pools with high volume relative to liquidity can compensate, low-volume volatile pools usually cannot.
• Stable and correlated pairs minimize the risk (short of a depeg); concentrated liquidity ranges multiply both fees and losses and require active management.