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Performance Metrics

This one handles all the standard risk-adjusted performance metrics you'd need for comparing funds or strategies. It covers Sharpe, Sortino, Information Ratio, Treynor, Calmar, Omega, and upside/downside capture ratios, plus M-squared. The formulas are straightforward and it includes annualization guidance, which matters because getting the sqrt(12) wrong on monthly Sharpe is a classic mistake. The worked examples walk through actual calculations and there's a nice comparison showing when Sortino trumps Sharpe for downside-focused investors. Use this when you need to evaluate whether a manager's returns justify the risk they took, or when someone asks if a fund is worth its volatility. The math is clean and the pitfalls section catches the usual errors.

skills.sh installs
746
GitHub stars
224
last updated
Aug 21, 2026

Install

$ npx -y skills add joellewis/finance_skills --skill performance-metrics --agent claude-code

Installs into .claude/skills of the current project.

Files

Performance Metrics

Core Concepts

Sharpe Ratio

The most widely used risk-adjusted performance measure. It divides excess return (over the risk-free rate) by total volatility.

SR = (R_p - R_f) / sigma_p
  • R_p: annualized portfolio return
  • R_f: annualized risk-free rate
  • sigma_p: annualized portfolio volatility (standard deviation of returns)

A higher Sharpe ratio indicates more return per unit of total risk. Typical benchmarks: SR < 0.5 is poor, 0.5-1.0 is acceptable, > 1.0 is strong, > 2.0 is exceptional.

Annualization: If computed from monthly data, SR_annual = SR_monthly * sqrt(12).

Sortino Ratio

Replaces total volatility with downside deviation, penalizing only harmful volatility (returns below a Minimum Acceptable Return).

Sortino = (R_p - R_f) / sigma_downside

where sigma_downside = sqrt((1/n) * sum(min(R_i - MAR, 0)^2)).

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Details

Repository
github.com/joellewis/finance_skills
Categories
Debugging, Finance & Trading
First seen
Jun 3, 2026

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