What it means
Beating a benchmark is easy to do once and hard to do repeatedly, and the information ratio is designed to separate the two. The numerator is active return, sometimes called alpha in loose usage, which is simply portfolio return minus benchmark return.
The denominator is tracking error, the standard deviation of that difference, which captures how much the portfolio's path wanders away from the index. The measure matters because investors are not buying returns in isolation; they are buying returns net of the risk of deviating from what they could have had for almost nothing in an index fund.
A manager who beats the benchmark by 5% one year and trails by 4% the next has produced excitement rather than skill. The information ratio penalises exactly that pattern.
In use, the ratio is calculated over a run of periods, typically monthly returns across three to five years, because a single year contains too little information to distinguish skill from chance. Institutional investors often treat a ratio of about 0.5 as respectable, 0.75 as good and anything sustained above 1.0 as exceptional.
Ratios computed over short windows should be treated with real scepticism. The information ratio is closely related to the Sharpe ratio but asks a different question.
The Sharpe ratio compares return above the risk-free rate to total volatility, whereas the information ratio compares return above a chosen benchmark to the volatility of that difference, which makes it the natural yardstick for anyone judging an active manager against an index. One nuance dominates the arguments about it.
The result depends entirely on the benchmark chosen, so a manager measured against an inappropriately easy index can look brilliant, and outside investing the same logic applies to any target-versus-actual comparison where someone gets to choose the target.
In practice
Real-world examples.
Example
A pension trustee board reviews three equity managers with active returns of 2.8%, 3.1% and 2.2%. Ranking on headline outperformance favours the second, but information ratios of 0.90, 0.52 and 0.88 show the second manager took far more deviation risk for that result, and the board reallocates accordingly.
Example
A wealth adviser explains to a client why a fund charging 0.85% a year is worth it. The fund's information ratio of 0.80 over five years shows steady value added, whereas a cheaper competitor with a ratio of 0.15 delivered outperformance no more reliable than a coin toss.
Example
A corporate treasury team applies the same logic to its cash management portfolio. Measuring returns against a short-dated government bond index, it finds an information ratio of 0.40, decides the modest extra return does not justify the credit risk, and shifts back towards the benchmark.
Think of it
“Information ratio shows skill in beating the benchmark-alpha relative to tracking error.
Formula
Calculation
Information Ratio = (Portfolio return - Benchmark return) / Tracking error
where tracking error is the standard deviation of the difference between portfolio and benchmark returns over the same periods.
Suppose a fund returned 11.5% over a year while its benchmark index returned 8.5%. The active return is 11.5% - 8.5% = 3.0%. If the standard deviation of the monthly return differences, annualised, was 4.0%, the information ratio is 3.0% / 4.0% = 0.75.
Compare that with a second, quieter fund that beat the same benchmark by only 1.2% but with a tracking error of just 1.0%. Its information ratio is 1.2% / 1.0% = 1.20, so despite a much smaller headline outperformance it delivered more excess return per unit of deviation risk, and an investor could in principle scale up that exposure to reach a similar outcome with more reliability.Case study
Seen in the real world.
Harbourgate Asset Partners is a fictional boutique fund manager created for this illustrative case study. Its marketing led with a single line: the flagship fund had beaten its benchmark in seven of the last ten years.
A prospective institutional investor asked for monthly data rather than annual headlines. The active returns averaged 2.4% a year, but the tracking error came out at 6.0%, giving an information ratio of 2.4% / 6.0% = 0.40. The three losing years included one where the fund trailed by 9%, which no client had been warned to expect.
Harbourgate responded by capping individual position sizes and reducing sector bets, which trimmed average active return to 1.8% but cut tracking error to 2.0%, lifting the information ratio to 0.90. Assets under management grew, because in this fictional example the investors cared more about reliability than about the biggest possible number.
Watch out
Common mistakes.
- Judging a manager on excess return alone. A 5% outperformance achieved with 15% tracking error is a weaker result than 2% achieved with 2%, because the first is far more likely to be luck.
- Calculating the ratio over a single year. Statistical noise dominates short samples, and three to five years of monthly data is the usual minimum for a meaningful figure.
- Confusing it with the Sharpe ratio. The Sharpe ratio measures return above the risk-free rate per unit of total volatility, while the information ratio measures return above a benchmark per unit of tracking error.
Questions
People also ask.
What counts as a good information ratio?
Around 0.5 is considered decent for an active manager, 0.75 is strong, and a ratio sustained above 1.0 over many years is rare and usually attracts a great deal of capital.
Can the information ratio be negative?
Yes, and a negative figure simply means the manager underperformed the benchmark on average, with the magnitude showing how badly relative to the risk taken.
Does the choice of benchmark really change the answer?
Completely, because both the numerator and the denominator are measured against it, so always check that the benchmark genuinely reflects the portfolio's investment universe.
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