Public Market Equivalent (PME) / Index Twin: measuring true alpha vs passive indexing (portfolio pme)

[iamsaquib8]

What

Roadmap idea. Active investors and stock pickers often track their portfolio returns (CAGR / XIRR) vs a benchmark, but comparing a customized schedule of staggered buys, sells, and dividends against a benchmark's point-to-point index return is mathematically misleading. Public Market Equivalent (PME) / Index Twin gives the mathematically exact answer to: "Did my active trading and stock picking actually beat buying a passive index fund on the exact same dates?"

Design

• stockwise portfolio pme [--benchmark NIFTYBEES|NIFTY500|SPY]:
  • Mirrors every historical trade in your tradebook on its exact date:
    • Every buy of ₹X on date D buys ₹X worth of the benchmark index ETF.
    • Every sell on date D sells the equivalent proportion from the benchmark twin.
    • Staggered dividends are reinvested or credited on matching dates.
  • Computes:
    • Current Portfolio Value vs Benchmark Index Twin Value (in exact ₹ / $).
    • True Net Rupee Value Added or Lost (Alpha in currency units) after all real-world transaction costs, STT, and taxes.
    • Kaplan-Schoar PME ratio and Direct Alpha annual percentage.
  • Also supports a custom blended asset benchmark (e.g. 60% Equity / 30% G-sec / 10% Gold).

Done when

• Accurately replays tradebook lot history into a synthetic benchmark twin.
• Computes exact rupee delta and PME metric against user-selected benchmark.
• Works offline from local tradebook and cached index history.
• Exposes --json and MCP tool.

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Upvote or comment below if you've tracked your performance against an index twin. What benchmarks do you benchmark yourself against? Ideas with community demand get scheduled on the roadmap.