docs: record portfolio capacity findings

docs/research/README.md

@@ -25,7 +25,7 @@ score, Structural S/R, the Gate Target Ladder, sentiment, fundamentals) is
 | 1.5× ATR initial stop | Real exit | Cuts losers fast |
 | 3× ATR trailing stop, 30-day max hold | Real exit | Best Sharpe of every exit tested |
 | Post-stop normal gate reset | Re-entry policy | Stop always closes; a later gate failure and subsequent fresh qualification define the next signal episode. The selected study arm reached Sharpe 1.77 / CAGR 48.3% at capacity 10; live scan-before-outcome timing is stricter (Sharpe 1.68 / CAGR 44.8% analogue). [Full study](post-stop-reentry.md) |
-| Max 10 concurrent positions, 1% risk per trade | Sizing | Cap never binds in practice |
+| Max 10 concurrent positions, 1% risk per trade | Sizing | The cap binds by signal count, but the focused bracket found negligible opportunity cost: cap 15 admitted every blocked setup and added only 0.0018 R/trade in affected paths. [Findings](portfolio-capacity-bracket-findings.md) |
 | Structural S/R | Human-facing product context | Clean, capped zones for charts and alerts; not read by the scanner |
 | Gate Target Ladder | Screening machinery | Volume-free transient proposals preserve the production candidate set exactly; never an exit |
 
@@ -61,7 +61,7 @@ invites overfitting.
 |---|---|
 | ATR trail multiple {1.5–4.0} | **Keep 3.0** — ≤2.0 whipsaws out the right tail; ≥2.5 is a plateau |
 | Momentum lookback (6-1, 3-1, 12-7 Novy-Marx, composites) | **Keep residual 12-1** — the others have IC ≈ 0 or weaker t-stats |
-| Selection cutoff {70…90} × book size {10, 15, 20} | **Keep 80 × 10** — monotonically worse in both directions |
+| Selection cutoff {70…90} × book size {10, 15, 20} | **Keep 80 × 10** — the focused daily bracket found no meaningful gain from cap 15, while weekly rank replacement hurt. [Findings](portfolio-capacity-bracket-findings.md) |
 | Position sizing (equal-weight, inverse-vol, risk-% sweep) | **Keep 1% fixed-fractional** |
 | Primary-target probability floor | **Keep 20%** — pruned lottery targets, 1,428 → 1,089 qualified, lifted Sharpe |
 | Primary-target R:R selector | **Keep 1.5** — target choice is intentionally independent of the later 2.0 activation floor |
@@ -146,6 +146,7 @@ knobs.
 | **Broader universe** | Composition changes factor signs (fip tug-of-war); vol-tilt on breadth is only a **directional hypothesis** (auth. −0.048 / t −1.36) | Any prod broaden must re-validate 80/20 tilt; offline research only; research.sqlite requires completion manifest |
 | **Forward paper-trade record** | The only true out-of-sample evidence the snapshot cannot give | Time; mark entries at actual near-close fill once ops ships |
 | **Better target model for clear-air names** | The return is demonstrably there (#2 wins on raw CAGR in *both* train and test); it's the *flat* 3× ATR target that makes it too expensive in risk | Needs a per-name model, not a constant k×ATR |
+| **Minimum effective-risk floor** | In cap-never-bound paths, the confounded 0.5% floor arm removed about 8% of fills while EV rose from 0.328 to 0.399 R and PF from 1.60 to 1.75, with exposure nearly unchanged | Run a single-variable A/B: cap 10 control versus cap 10 plus `min_initial_risk_fraction=0.005`. [Capacity findings](portfolio-capacity-bracket-findings.md) |
 
 ---
 
@@ -197,11 +198,15 @@ qualification. The [daily re-entry matrix](post-stop-reentry.md) supports this
 for the current 10-position book, but not as a universal rule for other
 portfolio capacities.
 
-Capacity itself is no longer considered settled. The current daily Phase A
-control rejects 519 qualified entries because the ten-slot book is full versus
-472 admitted trades. The older weekly “cap never binds” result is stale. The
-[frozen focused capacity bracket](portfolio-capacity-bracket.md) compares cap
-10, cap 15, cash-only unbounded, and weekly current-rank top 10 without tuning
-replacement variants or using a formal promotion gate.
+Capacity is now closed as a negative result. The current daily Phase A control
+does reject 519 qualified entries because the ten-slot book is full versus 472
+admitted trades, so the older weekly “cap never binds” claim was stale. But the
+clean cap-15 arm admitted every opportunity the strategy requested and added
+only 0.0018 R/trade in paths where cap 10 bound. Weekly current-rank replacement
+reduced mean EV and created substantial churn. Keep cap 10 and do not build the
+replacement policy. See the [frozen specification](portfolio-capacity-bracket.md)
+and the separate [capacity findings](portfolio-capacity-bracket-findings.md).
+The only open follow-up from that run is the confound-free 0.5% minimum
+effective-risk-floor A/B.
 
 The next real evidence is **forward**, not backward: the live paper-trade record.