What Factors Determine the Magnitude of Impermanent Loss for a Liquidity Provider?

The primary factor is the divergence in price between the two assets in the pool since the time of deposit. The greater the difference in price movement between the two paired tokens, the higher the impermanent loss.

For example, if one token triples in value while the other stays the same, the loss will be significant. The loss is "impermanent" because it only becomes permanent if the liquidity provider withdraws their funds before the prices return to the original ratio.