track-equity-cumulative-return

<essential_principles>

All cumulative return analyses use S&P 500 (^GSPC) as the fixed benchmark. This is a core methodology decision:

• S&P 500 represents the broad US equity market
• Provides consistent, comparable baseline across all analyses
• "vs Benchmark" = Stock Return - S&P 500 Return
• Positive vs Benchmark indicates outperformance (Alpha)

This is hardcoded and cannot be changed.

For cumulative return calculation, the base date is the last trading day of the previous year: