What Is the Difference between Impermanent Loss and a Standard Market Loss on a Held Asset?
A standard market loss is a direct loss in the dollar value of an asset simply by holding it as its price falls. Impermanent loss is an opportunity cost: the difference in value between the portfolio if held in the AMM pool versus if the assets were simply held in a wallet.
IL can occur even if both tokens' dollar values have increased, as long as their ratio has diverged.