6.1 Risk-Adjusted Performance Measures
Risk-adjusted performance measures are essential tools for evaluating investment performance, accounting for the level of risk taken to achieve returns.
The Sharpe Ratio:
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Definition:Â Measures excess return per unit of total risk (standard deviation)
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Formula: Sharpe Ratio = (Rp – Rf) / σp
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Interpretation:Â Higher indicates better risk-adjusted performance
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Applications:Â Performance evaluation of diversified portfolios, manager selection
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Limitations:Â Assumes normally distributed returns, uses standard deviation
The Treynor Ratio:
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Definition:Â Measures excess return per unit of systematic risk (beta)
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Formula: Treynor Ratio = (Rp – Rf) / βp
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Interpretation:Â Higher indicates better risk-adjusted performance
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Applications:Â Evaluating well-diversified portfolios
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Limitations:Â Requires accurate beta estimation, limited to diversified portfolios
Jensen’s Alpha:
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Definition:Â Measures excess return compared to CAPM expectations
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Formula: αp = Rp – [Rf + βp × (Rm – Rf)]
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Interpretation:Â Positive alpha indicates outperformance
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Applications:Â Manager performance evaluation, assessment of investment skill
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Limitations:Â Benchmark and model dependency
Information Ratio:
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Definition:Â Measures excess return relative to benchmark divided by tracking error
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Formula:Â IR = (Rp – Rb) / TE
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Interpretation:Â Higher indicates better risk-adjusted performance
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Applications:Â Evaluating active managers
6.2 Performance Attribution
Performance attribution decomposes portfolio returns into component parts to identify sources of value added or value lost.
The Attribution Framework:
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Allocation Effect:
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Contribution from asset allocation decisions
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Calculation: Σ (wpj – wbj) × (Rbj – Rb)
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Positive when overweighting outperforming asset classes
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Selection Effect:
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Contribution from security selection within asset classes
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Calculation: Σ wbj × (Rpj – Rbj)
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Positive when selected securities outperform benchmarks
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Interaction Effect:
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Contribution from the combination of allocation and selection
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Calculation: Σ (wpj – wbj) × (Rpj – Rbj)
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Practical Application:
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Attribution Levels:
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Top-level: Asset class allocation decisions
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Mid-level: Sector or industry allocation decisions
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Bottom-level: Individual security selection decisions
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Frequency of Attribution:
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Quarterly for most institutional portfolios
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Monthly for more active management
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Annual for strategic assessment
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Reporting:
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Clear and understandable presentation
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Identification of sources of value added
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Actionable insights for improvement
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6.3 Performance Evaluation in Practice
Performance evaluation in practice involves multiple considerations beyond simple return measurement.
Benchmark Selection:
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Appropriate Benchmarks:
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Match the portfolio’s investment style and strategy
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Consider the asset allocation and objectives
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Use recognized and established indices
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Custom Benchmarks:
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Blended benchmarks for multi-asset portfolios
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Reflect the portfolio’s strategic allocation
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Appropriate for specific investment mandates
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Consideration of Fees:
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Performance should be evaluated net of fees
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Fees impact net returns to clients
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Comparison to benchmarks should be on a net basis
Time Period Considerations:
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Multiple time periods should be evaluated
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Rolling periods provide insight into consistency
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Longer-term performance is more meaningful
Peer Group Comparison:
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Compare to appropriate peer groups
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Use consistent classification and methodology
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Provide context for peer group performance