What is Impermanent Loss?

Impermanent Loss (IL) is the difference between holding tokens in an automated market maker (AMM) liquidity pool versus holding them in your wallet.

Why it happens: AMMs maintain a constant product (x × y = k), so when one token's price changes, the pool automatically rebalances by trading to maintain the ratio. This rebalancing causes you to sell winners and buy losers.

When it matters: IL only applies to Strategy 1: ETH/USDC Liquidity Pool. The other strategies do not involve providing liquidity to two-sided pools.

It's "impermanent" because: If prices return to the original ratio, the loss disappears. However, if you withdraw at the new prices, the loss becomes permanent.

Impermanent Loss Formula

IL = 2 × √(price_ratio) / (1 + price_ratio) - 1

Where:

  • price_ratio = (New Price of ETH) / (Original Price of ETH)
  • IL = Loss as a decimal (negative value)

Convert to percentage: Multiply IL by 100

Example: If IL = -0.0572, then loss is -5.72%

Step-by-Step Example: ETH +50% Price Increase

1 Initial State
Initial ETH price: $2,000
Initial position value: $5,000 in ETH/USDC LP
This means: $2,500 in ETH (1.25 ETH) + $2,500 in USDC
2 Price Change
New ETH price: $3,000 (+50%)
price_ratio = $3,000 / $2,000 = 1.5
3 Calculate IL
IL = 2 × √(1.5) / (1 + 1.5) - 1
IL = 2 × 1.2247 / 2.5 - 1
IL = 2.4494 / 2.5 - 1
IL = 0.9798 - 1
IL = -0.0202 or -2.02%
4 Compare: LP vs. HODL
If you held 50/50 in wallet:
$2,500 in ETH → $3,750 (ETH +50%)
$2,500 in USDC → $2,500 (no change)
Total: $6,250 (+25% overall gain)

If you held in LP:
Pool rebalances due to constant product formula
Your share is now worth: $6,250 × 0.9798 = $6,123.75

Impermanent Loss: $6,250 - $6,123.75 = -$126.25 (-2.02%)
5 Net Return Including Fees
Capital Loss from IL: -$126.25
+ Trading Fees Earned (30% APR over 1 year): +$1,500
= Net Gain: +$1,373.75

Conclusion: Despite 2.02% IL, the 30% APR from fees far exceeds the loss.

Key Insight: Fees vs. Impermanent Loss

Liquidity providers profit when fee income > impermanent loss. In Strategy 1 (ETH/USDC LP), you earn 30% APR from trading fees, which typically outweighs IL unless ETH makes extreme moves (>2x or <-50%).

For this assignment: Calculate IL for each scenario, then add the 30% APR to determine net returns.

Pre-Computed IL Table (Use This to Save Time)

Price Change Price Ratio Impermanent Loss (%) LP Value vs. HODL
ETH -75% 0.25 -20.00% 80% of HODL value
ETH -50% 0.50 -5.72% 94.28% of HODL value
ETH -25% 0.75 -1.44% 98.56% of HODL value
ETH -10% 0.90 -0.23% 99.77% of HODL value
No Change 1.00 0.00% 100% of HODL value
ETH +10% 1.10 -0.23% 99.77% of HODL value
ETH +25% 1.25 -0.62% 99.38% of HODL value
ETH +50% (Scenario A) 1.50 -2.02% 97.98% of HODL value
ETH +100% 2.00 -5.72% 94.28% of HODL value
ETH +200% 3.00 -13.40% 86.60% of HODL value
ETH +300% 4.00 -20.00% 80% of HODL value

Scenario A: ETH +50%

Price Ratio: 1.5

IL: -2.02%

Calculation for $5,000 LP position:

Without IL: $5,000 → $6,250 (50/50 mix +25%)
With IL: $6,250 × 0.9798 = $6,123.75
IL Loss: -$126.25
+ Fee APR (30%): +$1,500
= Net: +$1,373.75

Scenario B: ETH Stable

Price Ratio: 1.0

IL: 0.00%

Calculation for $5,000 LP position:

Without IL: $5,000 (no price change)
With IL: $5,000 (no IL when price stable)
IL Loss: $0
+ Fee APR (30%): +$1,500
= Net: +$1,500

Scenario C: ETH -50%

Price Ratio: 0.5

IL: -5.72%

Calculation for $5,000 LP position:

Without IL: $5,000 → $3,750 (50/50 mix -25%)
With IL: $3,750 × 0.9428 = $3,535.50
IL Loss: -$214.50
+ Fee APR (30%): +$1,500
= Net: +$1,285.50

Note: Even in a bearish scenario, the 30% APR covers the IL loss. However, your total position value decreased due to ETH price decline.

Common Mistakes to Avoid

  • Forgetting the square root: It's √(price_ratio), not just price_ratio
  • Wrong price ratio: It's (new price / old price), not (old / new)
  • Ignoring fee income: Always add the 30% APR to your LP returns
  • Applying IL to non-LP strategies: Strategies 2, 3, 4, 5 have NO impermanent loss
  • Confusing IL with total return: IL is just the rebalancing loss; total return includes fees and price changes

Pro Tip: When to Worry About IL

IL is manageable when:

  • Price changes are moderate (±25%)
  • Fee APR is high (30% in this case)
  • You hold for a full year (more time to accumulate fees)

IL becomes problematic when:

  • One token pumps >2x (IL exceeds -5.72%)
  • Fee APR is low (e.g., 5% APR can't cover large IL)
  • You withdraw early (less time to earn fees)

© Joerg Osterrieder 2025-2026. All rights reserved.