diff --git a/collectors/universe_returns.py b/collectors/universe_returns.py
index f55c6a4..ff34fa0 100644
--- a/collectors/universe_returns.py
+++ b/collectors/universe_returns.py
@@ -23,6 +23,7 @@
 
 import boto3
 import pandas as pd
+from alpha_engine_lib.trading_calendar import add_trading_days as _add_trading_days
 
 logger = logging.getLogger(__name__)
 
@@ -224,7 +225,7 @@ def _trading_days_to_process(
         if nyse_is_trading_day(d):
             trading_days_seen += 1
             iso = d.isoformat()
-            fwd_5d = _add_business_days(d, 5)
+            fwd_5d = _add_trading_days(d, 5)
             if fwd_5d < today and iso not in existing:
                 out.append(iso)
         d -= timedelta(days=1)
@@ -328,9 +329,9 @@ def _build_rows_for_date(
 ) -> list[dict]:
     """Build universe_returns rows for a single eval_date."""
     eval_dt = date.fromisoformat(eval_date)
-    fwd_5d = _add_business_days(eval_dt, 5)
-    fwd_10d = _add_business_days(eval_dt, 10)
-    fwd_30d = _add_business_days(eval_dt, 30)
+    fwd_5d = _add_trading_days(eval_dt, 5)
+    fwd_10d = _add_trading_days(eval_dt, 10)
+    fwd_30d = _add_trading_days(eval_dt, 30)
 
     # Check that forward dates are in the past (returns can be computed)
     today = date.today()
@@ -350,7 +351,7 @@ def _build_rows_for_date(
     if not prices_t0:
         logger.warning("No prices for eval_date %s — may be a non-trading day", eval_date)
         # Try next business day
-        next_day = _add_business_days(eval_dt, 1)
+        next_day = _add_trading_days(eval_dt, 1)
         prices_t0 = polygon_client.get_grouped_daily(str(next_day))
         if not prices_t0:
             return []
@@ -424,14 +425,3 @@ def _pct_return(price_start: float | None, price_end: float | None) -> float | N
     if price_start is None or price_end is None or price_start <= 0:
         return None
     return (price_end / price_start) - 1.0
-
-
-def _add_business_days(start: date, n: int) -> date:
-    """Add n business days to a date (skipping weekends)."""
-    current = start
-    added = 0
-    while added < n:
-        current += timedelta(days=1)
-        if current.weekday() < 5:  # Mon-Fri
-            added += 1
-    return current
diff --git a/tests/test_universe_returns_trading_day.py b/tests/test_universe_returns_trading_day.py
new file mode 100644
index 0000000..d3f44c7
--- /dev/null
+++ b/tests/test_universe_returns_trading_day.py
@@ -0,0 +1,73 @@
+"""Trading-day eligibility filter in collectors/universe_returns.py.
+
+The arithmetic itself (add_trading_days) is locked in alpha-engine-lib's
+test_trading_calendar.py. These tests cover the data-module behavior:
+that _trading_days_to_process correctly delegates to NYSE-aware arithmetic
+and never enqueues weekends, holidays, or eval_dates whose 5d forward
+window has not yet closed.
+"""
+from __future__ import annotations
+
+from datetime import date
+
+from collectors.universe_returns import _trading_days_to_process
+
+
+class TestTradingDaysToProcess:
+    def test_excludes_weekends_and_holidays(self):
+        # Today = Sat 2026-04-25; lookback covers Good Friday 4/3 and the
+        # 4/4-5 weekend. None should appear in the result.
+        out = _trading_days_to_process(
+            today=date(2026, 4, 25),
+            max_lookback=20,
+            existing=set(),
+        )
+        forbidden = {"2026-04-03", "2026-04-04", "2026-04-05"}
+        assert forbidden.isdisjoint(set(out))
+
+    def test_eligibility_requires_fwd_5d_strictly_past(self):
+        # Today = 2026-04-25 (Sat). 4/20 (Mon) has fwd_5d = 4/27 (next Mon),
+        # which is NOT < today → ineligible.
+        out = _trading_days_to_process(
+            today=date(2026, 4, 25),
+            max_lookback=10,
+            existing=set(),
+        )
+        assert "2026-04-20" not in out
+
+    def test_existing_dates_filtered(self):
+        out = _trading_days_to_process(
+            today=date(2026, 4, 25),
+            max_lookback=20,
+            existing={"2026-04-17"},
+        )
+        assert "2026-04-17" not in out
+
+    def test_4_17_eligible_today(self):
+        # On 2026-04-25, 2026-04-17 (Fri) IS eligible because
+        # fwd_5d = 4/24 < 4/25 and it's a trading day.
+        out = _trading_days_to_process(
+            today=date(2026, 4, 25),
+            max_lookback=20,
+            existing=set(),
+        )
+        assert "2026-04-17" in out
+
+    def test_results_sorted_chronologically(self):
+        out = _trading_days_to_process(
+            today=date(2026, 4, 25),
+            max_lookback=30,
+            existing=set(),
+        )
+        assert out == sorted(out)
+
+    def test_holiday_eval_date_skips_correctly(self):
+        # 2026-04-02 (Thu before Good Friday): trading day. fwd_5d via
+        # NYSE-aware arithmetic = 2026-04-10 (skip Good Friday). 4/10 < 4/25
+        # → eligible, included.
+        out = _trading_days_to_process(
+            today=date(2026, 4, 25),
+            max_lookback=20,
+            existing=set(),
+        )
+        assert "2026-04-02" in out