The Calmar Ratio Explained: Why Drawdown Matters More Than Most Investors Realise

A 40% loss requires a 67% gain just to get back to where you started. This is the arithmetic reality of drawdown that most investors understand intellectually but rarely internalise deeply enough to act on.

The Calmar ratio was developed to quantify this relationship. Named after the California Managed Accounts Reports newsletter where it was first published in 1991, the Calmar ratio measures annual return relative to maximum drawdown - the largest peak-to-trough decline the investment has experienced over the measurement period.

It asks a simple question: how much annual return did this investment deliver for every percentage point of maximum loss it put investors through?

For SIPP investors in particular, the Calmar ratio captures something that neither the Sharpe nor the Sortino ratio fully addresses: the specific danger of a catastrophic drawdown near retirement.

A 50% loss at age 55, with a decade of remaining growth ahead, is a materially different problem from a 50% loss at 35 with three decades to recover. The Calmar ratio screens for stocks that have historically avoided those catastrophic peak-to-trough declines.

Alpesh Patel OBE is a hedge fund manager, Bloomberg TV alumnus, Financial Times author, and former Visiting Fellow at Corpus Christi College, Oxford. The Calmar ratio is the fifth and final screen in the Great Investments Programme quantitative framework.

The Calmar Ratio Formula and What It Measures

The formula is straightforward:

Calmar Ratio = Annualised Return ÷ Maximum Drawdown (expressed as a positive number)

Maximum drawdown is the largest peak-to-trough decline in the investment's price or value over the measurement period. It is typically calculated over a 3-year rolling period, though some practitioners use 5 years for a more robust measure. The GIP framework uses a 3-year look back consistent with standard institutional practice.

A Worked Example: Two Stocks, Same Return, Radically Different Drawdown

Consider two stocks, both returning 15% per year annualised over 3 years:

• Stock A: 15% annualised return, maximum drawdown of 20%. Calmar = 15 ÷ 20 = 0.75. Delivers reasonable return for its drawdown exposure.
  

• Stock B: 15% annualised return, maximum drawdown of 55%. Calmar = 15 ÷ 55 = 0.27. The same return, but achieved by putting investors through a 55% peak-to-trough loss. From which mathematically a 122% recovery was required.

The Calmar ratio differentiates clearly between these two stocks in a way that the Sharpe and Sortino ratios might not. Stock B's massive drawdown may have been followed by an equally dramatic recovery - leaving its Sortino ratio looking acceptable because the severe downside was eventually compensated. But for a SIPP investor who watched their pot fall 55% and either panicked and sold, or simply needed to withdraw funds during the trough, the recovery is irrelevant. The damage was already done.

What Is a Good Calmar Ratio?

• Below 0.5: Poor. The investment is exposing investors to disproportionate drawdown risk relative to the annual return it delivers.
  

• 0.5 to 1.0: Acceptable. The return roughly compensates for the drawdown. This is the GIP minimum threshold zone.
  

• Above 1.0: Good. The investment delivers more annual return than its maximum drawdown suggests, indicating a resilient, recovery-oriented price pattern.
  

• Above 2.0: Excellent. The investment is generating strong returns relative to its worst historical loss period. Typically only found in high-quality, durable compounders with defensible business models.

Why Drawdown Matters Disproportionately for SIPP Investors

For a 35-year-old building their SIPP over 30 years, a severe drawdown is painful but survivable. Markets have historically recovered from every major downturn within 5–10 years, and a long time horizon means the portfolio can compound back and beyond the previous peak.

For a 58-year-old with £400,000 in their SIPP and 7 years to planned retirement, a 45% drawdown leaves them with £220,000 and a mathematical requirement to deliver 82% returns just to return to £400,000 - before accounting for inflation, before accounting for any planned contributions stopping, and before accounting for the psychological impact on decision-making under pressure.

This is what academics call sequence of returns risk and it is the primary reason the GIP framework includes the Calmar ratio. The framework's goal is not just to maximise returns. It is to maximise returns while systematically avoiding the stocks that have historically demonstrated a capacity to inflict severe, portfolio-defining losses.

Completing the GIP Five-Metric Framework

The Calmar ratio is the fifth screen in the GIP framework. The five together are:

• CROCI above 10%: The business genuinely generates cash on its invested capital.

• PEG below 1.0: The stock is not overvalued relative to its growth rate.

• Sortino above 1.0: Returns adequately compensate for downside volatility specifically.

• Sharpe ratio: Returns adequately compensate for total volatility.

• Calmar ratio: Returns adequately compensate for the maximum historical drawdown.

Each screen addresses a different dimension of investment quality and risk. Together, they identify businesses that are cash-generative and reasonably valued (CROCI + PEG), with price behaviour that efficiently compensates for total risk, downside risk, and worst-case loss scenarios (Sharpe + Sortino + Calmar). From a universe of approximately 8,000 stocks, typically 40–50 pass all five criteria in any given week.

Frequently Asked Questions: The Calmar Ratio

What is a good Calmar ratio?

A Calmar ratio above 0.5 is considered acceptable; above 1.0 is good; above 2.0 is excellent. For context, the S&P 500 index has historically produced a Calmar ratio of approximately 0.3–0.5 over rolling 3-year periods, which includes major drawdowns like 2008–09 and the 2020 COVID crash. Stocks with sustained Calmar ratios above 1.0 have typically been high-quality businesses with durable competitive positions that recover quickly from market downturns.

How is the Calmar ratio different from the Sharpe ratio?

The Sharpe ratio uses standard deviation (average volatility) as its risk measure. The Calmar ratio uses maximum drawdown (the worst single loss experience) as its risk measure. Standard deviation is an average of all return fluctuations; maximum drawdown is the single worst episode. The Calmar ratio captures tail risk — the kind of extreme downside that standard deviation can understate in practice.

Where was the Calmar ratio developed?

The Calmar ratio was developed by Terry W. Young and first published in the California Managed Accounts Reports newsletter in 1991. The name 'Calmar' is derived from that publication. It was originally designed for evaluating commodity trading advisors (CTAs) and managed futures funds, where drawdown management is a central investment discipline. It has since been widely adopted in equity investing and hedge fund evaluation.

Why do SIPP investors need to care about maximum drawdown?

Because a SIPP has a finite investment horizon that ends at retirement. A severe drawdown in the final decade before retirement cannot always be fully recovered before withdrawals begin. Sequence of returns risk — the impact of poor returns early in a drawdown phase — is one of the most well-documented risks in retirement planning. The Calmar ratio screens for stocks that have historically avoided the catastrophic drawdowns that create this problem.

How does the GIP framework calculate the Calmar ratio?

The GIP Approved List calculates the Calmar ratio for all 8,000 stocks in the investable universe weekly, using a 3-year rolling period for both the annualised return and the maximum drawdown calculation. Members do not need to calculate it themselves — stocks that fail the Calmar screen are excluded from the Approved List before it reaches them. The five-metric screen is run simultaneously, and only stocks passing all five criteria appear on the list that week.

The GIP Approved List applies all five metrics — CROCI, PEG, Sortino, Sharpe, and Calmar — to 8,000 stocks every week. To understand how the full framework works and how to apply it, book a free portfolio review here. Or start with the full programme at alpeshpatel.com/shares.

Sources & Further Reading

Young, T.W. (1991) — California Managed Accounts Reports. Original publication introducing the Calmar ratio for evaluating managed futures and CTA performance.

Sharpe, W.F. (1966) — 'Mutual Fund Performance'. Journal of Business. Foundational risk-adjusted return metric alongside which Calmar sits. jstor.org/stable/2351741

Bengen, W.P. (1994) — 'Determining Withdrawal Rates Using Historical Data'. Journal of Financial Planning. Foundational research on sequence of returns risk and retirement portfolio drawdown. fp.org

AQR Capital Management — Research on drawdown risk, tail risk management, and factor investing. aqr.com/insights/research

Financial Times — Quantitative investing, drawdown risk, and retirement portfolio construction. ft.com/investing

Disclaimer: This article is for educational purposes only and does not constitute personal financial guidance. All investing carries risk. Past performance is not a reliable indicator of future results.

Alpesh Patel OBE

www.campaignforamillion.com