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Risk

Ulcer Index

Menno van Ravels - Alpha Factory

By - 13 years in crypto, 3 bear markets survived, zero paid promotions

AI Quick Summary: Ulcer Index Summary

Term

Ulcer Index

Category

Risk

Definition

The Ulcer Index measures the depth and duration of portfolio drawdowns — literally quantifying how 'stomach-churning' an investment is to hold through.

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The Ulcer Index measures the depth and duration of portfolio drawdowns — literally quantifying how 'stomach-churning' an investment is to hold through. Higher Ulcer Index means more severe or prolonged drawdowns. It is used as an alternative risk measure to volatility when evaluating portfolios with severe downside risk.

The Ulcer Index was developed by Peter Martin in 1987, published in "The Investor's Guide to Fidelity Funds." Its name reflects its intent: measuring how much an investment causes psychological distress through prolonged losses.

**Formula:** UI = √(mean of squared % drawdowns over all periods)

**Step by step:** 1. For each period, calculate the % drawdown from the most recent high: D_i = (Price_i / MaxPrice) - 1 2. Square each drawdown: D_i² 3. Calculate the mean of squared drawdowns 4. Take the square root

**Why squared drawdowns:** Squaring emphasizes larger and longer drawdowns disproportionately — consistent with how psychologically painful sustained large losses are vs. brief small ones. A 20% drawdown persisting for 6 months "hurts" much more than a 20% drawdown lasting 1 week.

**Ulcer Performance Index (UPI):** Return / Ulcer Index — analogous to the Sharpe ratio but using Ulcer Index as the risk measure. Higher UPI = better performance per unit of drawdown-pain.

**Crypto Ulcer Index:** Crypto portfolios have extremely high Ulcer Indices due to frequent and deep drawdowns. A portfolio's Ulcer Index can be dramatically reduced by: - Adding stablecoin allocation (reduces drawdown exposure) - Using trend-following exit rules - Maintaining higher cash position during bear markets

**Comparison with Sharpe/Sortino:** - Sharpe uses standard deviation (symmetric) - Sortino uses downside deviation (negative moves) - Ulcer Index uses drawdown duration × magnitude (the full pain experience) For long-term crypto investors, the Ulcer Index often better captures actual investor experience.

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Frequently Asked Questions

How is the Ulcer Index different from maximum drawdown?

Maximum drawdown captures only the single worst event. The Ulcer Index captures all drawdowns weighted by their magnitude and duration. A portfolio might have an identical max drawdown to another but a much higher Ulcer Index if it experiences frequent 15–20% drawdowns vs. one rare large drawdown followed by immediate recovery. The Ulcer Index represents the cumulative psychological burden of holding through losses.

What is a good Ulcer Index for a crypto portfolio?

No universal standard exists, but lower is better. A Bitcoin-only portfolio historically has a very high Ulcer Index due to severe, prolonged bear market drawdowns. A diversified portfolio (50% BTC, 30% ETH, 20% stablecoins) has a materially lower Ulcer Index. Compare within asset classes — a strategy with Ulcer Index of 15 vs. another at 30 in the same asset class means the first has substantially less drawdown pain.

What is the Ulcer Performance Index (UPI)?

UPI = (Average return - Risk-free rate) / Ulcer Index. It's the Sharpe ratio's equivalent using Ulcer Index as risk. A higher UPI means better return per unit of drawdown. It's particularly useful for comparing strategies where one has lower returns but much lower drawdown pain — the UPI captures whether the return sacrifice is worth the drawdown reduction.

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