You deposit ETH and a stablecoin into a liquidity pool, collect a fee on every swap, withdraw six months later — and discover that if you'd just held both assets in your wallet, you'd have more money. Not "about the same." More. The fees didn't save you. The pool beat you, and you never saw how.
That's impermanent loss. It doesn't make headlines, it isn't a hack, nobody steals it from you. It's baked directly into the math of how the pool works, and almost everyone who provides liquidity for the first time only learns about it afterward, staring at a number that doesn't add up.
What's actually happening inside the pool
A classic automated market maker (AMM) pool — Uniswap and its many clones — holds two assets at a strict ratio governed by a formula: the product of the two quantities has to stay constant. In plain terms: if the pool holds ETH and USDC, it's always willing to sell one asset for the other at a rate the formula calculates from the current reserves.
Here's the part people miss: a pool isn't a vault. It's a machine that continuously rebalances your assets against you. When ETH's price rises, traders buy the now-cheap ETH out of the pool with the now-expensive USDC, until the ratio catches up with the market. Net effect: the pool automatically sells your appreciating asset and accumulates the depreciating one. You didn't choose to do that. The algorithm chose it for you, because that's what the formula does.
The word "impermanent" comes from the fact that if prices return to their original ratio, the loss disappears — you get back exactly what you put in. But prices rarely return. And the moment you withdraw while the ratio has shifted, the loss locks in and becomes permanent. The name isn't optimism. It's a trap built into the expectation.
The numbers that sober you up
Here's a rough but honest rule of thumb to keep in your head: if one of the two pool assets doubles in price relative to the other, your loss versus simply holding (HODLing) both is around 5.7%. A 4x move brings it to roughly 20%. A 5x move, nearly 25.5%. The formula is symmetric — it doesn't matter which of the two assets is the one that rips, you lose either way, because the pool always sells whichever one is appreciating.
This isn't a hypothetical about exotic altcoins. It happens in a plain ETH/stablecoin pair during a normal bull run. Right at the moment your asset "took off" and you'd already mentally spent the gain, the pool was quietly taking it back — a little at a time, swap by swap — and selling it to the traders who were riding that exact price move.
Why fees don't always cover it
"But I'm earning a fee on every swap" sounds convincing until you actually compare the magnitudes. In deep, liquid pairs on mature networks, fees really can outpace impermanent loss over long stretches — that's the reason pairs like ETH/USDC on major DEXes exist and are full of capital. But in volatile pairs, new tokens, or periods of sharp price movement, the swap fee (usually a fraction of a percent) simply can't accumulate faster than the price gap between the two assets grows.
There's a second layer of pain: concentrated liquidity pools, like Uniswap v3, amplify the effect. You pick a narrow price range for higher fee yield — and get multiplied impermanent loss if the price moves outside that range. Higher potential reward comes with a higher-leverage loss on the other side of the trade. That's not a protocol bug. It's a direct tradeoff that got marketed to you as "capital efficiency."
Our Record: a liquidity pool is a contract where you hand over your assets' Ba — their mobility, the right to decide when to hold and when to sell — to an impersonal formula. The formula isn't malicious or benevolent; it just executes its rule without stopping, swap after swap, while you sleep. This isn't Isfet in the predatory sense — nobody is secretly stealing from you. But it isn't full Ma'at either: fair distribution requires that you see the price of your choice in advance, not discover it after the fact in a number that no longer matches what you put in.
When providing liquidity actually makes sense
It isn't all bleak — you just need a precise sense of where IL doesn't eat the upside:
- Stablecoin/stablecoin pairs (USDC/DAI and similar) — both assets barely move relative to each other, so IL trends toward zero and the fees accrue nearly clean.
- Correlated-asset pairs (say, ETH and a staked-ETH derivative) — prices move almost in lockstep, the gap stays narrow, IL is minimal.
- Deep pairs with high trading volume — where fee flow can genuinely outrun even a meaningful IL through sheer scale.
- A deliberately narrow range in concentrated liquidity — but only if you're actively managing the position and ready to move it, not setting and forgetting.
Outside those cases — especially in a pair involving a volatile altcoin — treat IL not as a side risk but as a baseline condition of the trade, one you price in before you deposit, not after you withdraw.
Do this before you deposit
Before you put liquidity into any pool, run the scenario: what if one asset doubles, what if it halves? Impermanent loss calculators (there are dozens, a search away) give you a concrete loss figure for different price moves — compare it to that pool's projected annual fee yield, which is also visible on most DEX interfaces. If the IL at a plausible price swing exceeds the annual fee income, you're not earning on that pool — you're slowly selling your appreciating asset for a depreciating one, just through an intermediary with a nice interface.
Liquidity provision isn't passive income by default. It's a position with its own non-obvious risk mechanics, and the only defense against it is understanding the formula before you enter — not reading about it after the numbers in your wallet stop making sense.