The Treynor ratio is excess return per unit of systematic (market) risk.
What it is
The Treynor Ratio, named after economist Jack Treynor, measures how much return a portfolio earns above the risk-free rate for each unit of market (systematic) risk it carries. Risk is captured by beta, which gauges sensitivity to the overall market, rather than by total volatility. It is closely related to the Sharpe ratio but swaps standard deviation for beta in the denominator. A higher value means more reward per unit of market risk.
Why it matters
Because beta only captures market risk, the Treynor Ratio is most meaningful for a well-diversified portfolio where company-specific (unsystematic) risk has already been diversified away. The key pitfall: the ratio is misleading for a concentrated single-stock holding (where total risk, not just beta, matters) and breaks down when beta is near zero (it blows up) or negative (a negative excess return divided by a negative beta produces a deceptively positive score). Always check the beta denominator before trusting the result.
How it's calculated
Subtract the risk-free rate (typically a short-term government T-bill yield) from the portfolio's return to get the excess return, then divide that excess by the portfolio's beta. Returns are usually annualized, and beta is estimated by regressing the portfolio's returns against a market benchmark. The result expresses excess return per unit of beta.
How Quintarthai uses it
Pull a stock's beta from its deep-analysis page at /app/ and pair it with its return to gauge market-risk-adjusted performance, and use the Knowledge Base to compare the Treynor Ratio against the Sharpe ratio for diversified versus concentrated holdings.
Cross-border note. For a Canadian-dollar portfolio the natural risk-free proxy is the Government of Canada 3-month T-bill yield, while a US-dollar portfolio uses the US 3-month Treasury bill; beta should be measured against a matching benchmark (e.g. S&P/TSX Composite for Canada, S&P 500 for the US). Mixing a US risk-free rate with a TSX-based beta, or ignoring CAD/USD currency effects, distorts the comparison.
FAQ
When should I use the Treynor Ratio instead of the Sharpe ratio?
Use the Treynor Ratio when the portfolio is well-diversified, so that only systematic (market) risk remains and beta is the relevant risk measure. For a concentrated or single-stock holding, the Sharpe ratio is more appropriate because it captures total volatility, not just market risk.
Why can a Treynor Ratio give a misleading positive number?
If beta is negative, a negative excess return divided by a negative beta yields a positive ratio that falsely signals good performance. A near-zero beta also distorts the result by making the ratio explode, so always inspect the denominator before drawing conclusions.
Check your understanding
Two diversified funds each return 10% with a 3% risk-free rate. Fund A has a beta of 1.0; Fund B has a beta of 2.0. Which has the better Treynor Ratio, and why?
Both have a 7% excess return, but Fund A's Treynor is 7% ÷ 1.0 = 7.0 versus Fund B's 7% ÷ 2.0 = 3.5, so Fund A delivered more return per unit of market risk.