diff --git a/backend/app/market_time.py b/backend/app/market_time.py
index d25e212..fa38d47 100644
--- a/backend/app/market_time.py
+++ b/backend/app/market_time.py
@@ -44,6 +44,8 @@ def trading_minutes_elapsed_from_dt(dt: datetime) -> float:
     - 开盘前 = 0; 午休(11:30-13:00) = 120(保持上午累计); 收盘后 = 240。
     - 非交易日(周末) = 240 (视作全天, 避免量比被折算成 0)。
     """
+    if dt.weekday() >= 5:
+        return float(_TRADING_TOTAL_MINUTES)
     t = dt.time()
     if t < _MORNING_START:
         return 0.0
diff --git a/backend/tests/test_trading_minutes_elapsed.py b/backend/tests/test_trading_minutes_elapsed.py
new file mode 100644
index 0000000..b8dffb8
--- /dev/null
+++ b/backend/tests/test_trading_minutes_elapsed.py
@@ -0,0 +1,61 @@
+"""当日已交易分钟数 — 量比时间折算的分母来源。
+
+compute_enriched_today 用 `time_factor = 240 / elapsed_minutes` 把盘中的部分
+成交量折算到全天量级。周末/非交易日没有"当日已交易分钟", 必须按全天 240 算,
+否则手动刷新一次行情就会把全市场量比放大 240/已过分钟数 倍, 「放量」
+(vol_ratio_5d >= 2) 整片误触发。
+"""
+from __future__ import annotations
+
+from datetime import datetime, timedelta, timezone
+
+import pytest
+
+from app.market_time import (
+    trading_minutes_elapsed_from_dt,
+    trading_minutes_elapsed_from_ts,
+)
+
+CN = timezone(timedelta(hours=8))
+
+
+def _ms(dt: datetime) -> int:
+    return int(dt.timestamp() * 1000)
+
+
+@pytest.mark.parametrize(
+    ("moment", "label"),
+    [
+        (datetime(2026, 9, 12, 9, 31, tzinfo=CN), "周六 开盘后 1 分钟"),
+        (datetime(2026, 9, 12, 10, 0, tzinfo=CN), "周六 上午"),
+        (datetime(2026, 9, 13, 14, 0, tzinfo=CN), "周日 下午"),
+    ],
+)
+def test_weekend_counts_as_a_full_session(moment, label):
+    assert trading_minutes_elapsed_from_dt(moment) == 240.0, label
+
+
+def test_weekend_timestamp_also_counts_as_full_session():
+    """行情戳落在周末 (源侧异常戳) 时同样按全天算。"""
+    assert trading_minutes_elapsed_from_ts(_ms(datetime(2026, 9, 12, 10, 0, tzinfo=CN))) == 240.0
+
+
+@pytest.mark.parametrize(
+    ("moment", "expected", "label"),
+    [
+        (datetime(2026, 9, 11, 9, 0, tzinfo=CN), 0.0, "周五 开盘前"),
+        (datetime(2026, 9, 11, 9, 31, tzinfo=CN), 1.0, "周五 9:31"),
+        (datetime(2026, 9, 11, 11, 30, tzinfo=CN), 120.0, "周五 午休起点"),
+        (datetime(2026, 9, 11, 12, 30, tzinfo=CN), 120.0, "周五 午休中"),
+        (datetime(2026, 9, 11, 14, 0, tzinfo=CN), 180.0, "周五 14:00"),
+        (datetime(2026, 9, 11, 15, 30, tzinfo=CN), 240.0, "周五 收盘后"),
+    ],
+)
+def test_weekday_session_progress_unchanged(moment, expected, label):
+    """交易日的分段折算不受影响 (回归保护)。"""
+    assert trading_minutes_elapsed_from_dt(moment) == expected, label
+
+
+def test_missing_timestamp_still_counts_as_full_session():
+    assert trading_minutes_elapsed_from_ts(None) == 240.0
+    assert trading_minutes_elapsed_from_ts(0) == 240.0