The capacity bracket study (reports/portfolio-construction-prod505-capacity-
bracket-daily-v1) showed a book whose count cap never binds earns +1.1pp CAGR
over the old 10 -- 51 of 175 paired cohorts better, 2 worse -- at unchanged
drawdown (+0.007pp) and better Calmar in 51 of the 52 cohorts that moved.
The headline EV-per-trade delta is ~0 (+0.001), which is the trap: capacity
does not change trade quality, it changes trade COUNT. Flat EV/trade means the
blocked entries were just as good as the taken ones, so refusing them cost their
whole contribution to return. Judge capacity on CAGR, never on EV per trade.
15 is headroom, not a target. cap15 peaked at 12 positions with zero full-book
skips, so cash plus SIM_NOTIONAL_CAP is the real ceiling and 15/20/None are the
same experiment.
SIM_MAX_POSITIONS and the shadow book's DEFAULT_CAPACITY move together to keep
backtest and production in parity. Historical research arms pass max_positions
explicitly, so their labels and past results are unaffected.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
dennisthiessenandClaude Opus 5
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