diff --git a/app/services/backtest_service.py b/app/services/backtest_service.py
index 1c06c87..317f3e7 100644
--- a/app/services/backtest_service.py
+++ b/app/services/backtest_service.py
@@ -1701,7 +1701,14 @@ def _gate_ablation(candidates: list[dict], activation: dict, threshold: float) -
 # the QUALIFIED setups at their detection close, best momentum first while
 # slots and cash allow.
 SIM_STARTING_CAPITAL = 10_000.0
-SIM_MAX_POSITIONS = 10
+# Headroom, not a target: the count cap should never bind. The capacity study
+# (reports/portfolio-construction-prod505-capacity-bracket-daily-v1) showed a book
+# that never hits the count cap earns +1.1pp CAGR over the old 10 (51 cohorts of 175
+# better, 2 worse) at unchanged drawdown, because the blocked entries were as good as
+# the taken ones — capacity costs trade COUNT, not trade quality. The real ceiling is
+# cash plus SIM_NOTIONAL_CAP, which saturates the book near 12 positions, so 15/20/None
+# are the same experiment. Judge any future change here on CAGR, never on EV per trade.
+SIM_MAX_POSITIONS = 15
 SIM_RISK_PER_TRADE = 0.01  # fraction of equity risked per position (entry→stop)
 SIM_NOTIONAL_CAP = 0.20    # max fraction of equity per position (no margin)
 _EULER_MASCHERONI = 0.5772156649015329
diff --git a/app/services/shadow_book_service.py b/app/services/shadow_book_service.py
index 87c992f..9697a66 100644
--- a/app/services/shadow_book_service.py
+++ b/app/services/shadow_book_service.py
@@ -40,10 +40,12 @@ KEY_CAPACITY = "shadow_book_capacity"
 KEY_RISK_PCT = "shadow_book_risk_pct"
 KEY_START_EQUITY = "shadow_book_start_equity"
 
-# Matches the validated configuration: 10-position book, 1% fixed-fractional
-# risk. Start equity is only a sizing base — comparisons are drawn in percent
-# and R-multiples, never in raw currency.
-DEFAULT_CAPACITY = 10
+# Matches the validated configuration: 1% fixed-fractional risk, and a count cap
+# set as headroom rather than a target — see backtest_service.SIM_MAX_POSITIONS,
+# which this must track. NOTIONAL_CAP below saturates the book near 12 positions,
+# so the count cap should simply never bind. Start equity is only a sizing base —
+# comparisons are drawn in percent and R-multiples, never in raw currency.
+DEFAULT_CAPACITY = 15
 DEFAULT_RISK_PCT = 1.0
 DEFAULT_START_EQUITY = 100_000.0