diff --git a/kis_trader/backtest/breakout_portfolio_backtest.py b/kis_trader/backtest/breakout_portfolio_backtest.py
index 9e98041..c95795f 100644
--- a/kis_trader/backtest/breakout_portfolio_backtest.py
+++ b/kis_trader/backtest/breakout_portfolio_backtest.py
@@ -32,7 +32,7 @@ from kis_trader.strategies.breakout import (
     normalize_breakout_max_loss_krw,
 )
 from kis_trader.strategies.base import is_strategy_eod_bar
-from kis_trader.engine.tail_engine import compute_atr_series
+from kis_trader.engine.atr_series import compute_atr_series
 
 
 def _entry_atr_at(ctx: Dict[str, Any], idx: int) -> float:
diff --git a/kis_trader/engine/atr_series.py b/kis_trader/engine/atr_series.py
new file mode 100644
index 0000000..fe2e170
--- /dev/null
+++ b/kis_trader/engine/atr_series.py
@@ -0,0 +1,37 @@
+#!/usr/bin/env python3
+"""
+kis_trader/engine/atr_series.py — ATR 시리즈 (엔진·전략 공통, 순환 import 방지)
+"""
+from __future__ import annotations
+
+from typing import Dict, List, Optional
+
+
+def compute_atr_series(candles: List[Dict], period: int = 14) -> List[Optional[float]]:
+    """
+    ATR(Average True Range) 변동성 지표 계산기 (엔진 내부용).
+
+    ■ RMA(Wilder's Smoothing) 방식 — TradingView 기본과 동일 (2026-06 SMA→RMA 전환).
+      ATR_t = (ATR_{t-1} × (period-1) + TR_t) / period
+      · 첫 ATR(인덱스 period)은 SMA(TR[1..period])로 시드.
+      · SMA 대비: 급락(큰 TR)이 14봉 지나도 '계단식 급락' 없이 완만히 감쇠 →
+        급변장에서 손절/목표가가 덜 출렁임.
+    """
+    atr_list: List[Optional[float]] = [None] * len(candles)
+    if len(candles) < period + 1:
+        return atr_list
+    trs = [0.0] * len(candles)
+    for i in range(1, len(candles)):
+        hi = float(candles[i]["high"])
+        lo = float(candles[i]["low"])
+        prev_cl = float(candles[i - 1]["close"])
+        trs[i] = max(hi - lo, abs(hi - prev_cl), abs(lo - prev_cl))
+
+    # 첫 ATR(인덱스 period): TR[1..period] 단순 평균으로 시드 (Wilder 초기값)
+    prev_atr = sum(trs[1:period + 1]) / period
+    atr_list[period] = prev_atr
+    # 이후: Wilder RMA 누적 감쇠 (이전 ATR×(n-1) + 오늘 TR) / n
+    for i in range(period + 1, len(candles)):
+        prev_atr = (prev_atr * (period - 1) + trs[i]) / period
+        atr_list[i] = prev_atr
+    return atr_list
diff --git a/kis_trader/engine/momentum_engine.py b/kis_trader/engine/momentum_engine.py
index 37eb6fc..f9cccda 100644
--- a/kis_trader/engine/momentum_engine.py
+++ b/kis_trader/engine/momentum_engine.py
@@ -32,7 +32,7 @@ from kis_trader.engine.momentum_env_keys import (
     momentum_env_int,
     _legacy_float,
 )
-from kis_trader.strategies.base import is_strategy_eod_bar
+from kis_trader.engine.strategy_eod import is_strategy_eod_bar
 from kis_trader.utils.env import get_env_int
 
 MOMENTUM_STRATEGY_ID = "MOMENTUM"
diff --git a/kis_trader/engine/strategy_eod.py b/kis_trader/engine/strategy_eod.py
new file mode 100644
index 0000000..1ebfe80
--- /dev/null
+++ b/kis_trader/engine/strategy_eod.py
@@ -0,0 +1,132 @@
+#!/usr/bin/env python3
+"""
+kis_trader/engine/strategy_eod.py — 전략 EOD 시각 판정 (실매·백테·엔진 공통)
+=====================================================================
+strategies.base 와 engine 간 순환 import 방지용 — 엔진은 이 모듈만 import.
+"""
+from __future__ import annotations
+
+from datetime import datetime as dt
+from typing import Any, Dict, Tuple
+
+
+def parse_eod_hm(raw: str, default: str = "15:25") -> Tuple[int, int]:
+    """EOD 시각 문자열 → (시, 분). ``1515`` / ``15:15`` 모두 허용."""
+    s = str(raw or default).strip()
+    if not s or s.lower() == "none":
+        s = default
+    if ":" in s:
+        parts = s.split(":", 1)
+        try:
+            return int(parts[0]), int(parts[1])
+        except (ValueError, TypeError):
+            pass
+    if len(s) == 4 and s.isdigit():
+        return int(s[:2]), int(s[2:])
+    try:
+        hh, mm = [int(x) for x in s.split(":")]
+        return hh, mm
+    except Exception:
+        return 15, 25
+
+
+def is_live_eod_now(
+    enabled: bool,
+    eod_hm: str,
+    now: dt,
+    *,
+    default_hm: str = "15:25",
+) -> bool:
+    """실매 EOD 당일청산 시각 도달 여부."""
+    if not enabled:
+        return False
+    eod_hh, eod_mm = parse_eod_hm(eod_hm, default_hm)
+    return (now.hour > eod_hh) or (now.hour == eod_hh and now.minute >= eod_mm)
+
+
+# 전략별 EOD env 키 — 실매·백테·파라서치 공통
+_STRATEGY_EOD_SPEC: Dict[str, Tuple[str, str, bool, str, str]] = {
+    "BREAKOUT": ("BREAKOUT_EOD_ENABLED", "BREAKOUT_EOD_HM", True, "15:15", ""),
+    "MOMENTUM": ("MOMENTUM_EOD_ENABLED", "MOMENTUM_EOD_HM", True, "15:25", "MOMENTUM_FORCE_EOD_EXIT"),
+    "TAIL": ("TAIL_EOD_ENABLED", "TAIL_EOD_HM", True, "15:25", "force_eod_exit"),
+    "SHORT": ("TAIL_EOD_ENABLED", "TAIL_EOD_HM", True, "15:25", "force_eod_exit"),
+}
+
+
+def _params_truthy_bool(val: Any, default: bool) -> bool:
+    if val is None or val == "" or val == "None":
+        return default
+    if isinstance(val, bool):
+        return val
+    return str(val).strip().lower() in ("1", "true", "t", "y", "yes", "on")
+
+
+def resolve_strategy_eod_params(
+    params: Dict[str, Any],
+    strategy_id: str,
+) -> Tuple[bool, str]:
+    """params → (eod_enabled, eod_hm). UI ``eod_enabled``/``eod_hm`` 우선, 없으면 env 키."""
+    sid = str(strategy_id or "").strip().upper()
+    if sid == "SHORT":
+        sid = "TAIL"
+    spec = _STRATEGY_EOD_SPEC.get(sid)
+    if spec is None:
+        return False, "15:25"
+    en_key, hm_key, def_en, def_hm, leg_key = spec
+
+    if "eod_enabled" in params:
+        enabled = _params_truthy_bool(params.get("eod_enabled"), def_en)
+    elif en_key in params:
+        enabled = _params_truthy_bool(params.get(en_key), def_en)
+    elif leg_key and leg_key in params:
+        enabled = _params_truthy_bool(params.get(leg_key), def_en)
+    else:
+        enabled = def_en
+
+    raw_hm = params.get("eod_hm")
+    if raw_hm not in (None, "", "None"):
+        eod_hm = str(raw_hm).strip()
+    elif params.get(hm_key) not in (None, "", "None"):
+        eod_hm = str(params.get(hm_key)).strip()
+    else:
+        eod_hm = def_hm
+    return enabled, eod_hm
+
+
+def is_backtest_eod_bar(
+    candle_time: str,
+    enabled: bool,
+    eod_hm: str,
+    *,
+    default_hm: str = "15:25",
+) -> bool:
+    """백테 1분봉/스캔키 — 실매 ``is_live_eod_now`` 와 동일 시각 기준."""
+    if not enabled:
+        return False
+    eod_hh, eod_mm = parse_eod_hm(eod_hm, default_hm)
+    t = str(candle_time).strip()
+    if len(t) < 12:
+        return False
+    try:
+        bar_hh = int(t[8:10])
+        bar_mm = int(t[10:12])
+    except (ValueError, TypeError):
+        return False
+    return (bar_hh > eod_hh) or (bar_hh == eod_hh and bar_mm >= eod_mm)
+
+
+def is_strategy_eod_bar(
+    candle_time: str,
+    params: Dict[str, Any],
+    strategy_id: str,
+) -> bool:
+    """전략 params + 봉시각 → EOD 청산 여부 (실매와 동일 키·시각)."""
+    sid = str(strategy_id or "").strip().upper()
+    if sid == "SHORT":
+        sid = "TAIL"
+    spec = _STRATEGY_EOD_SPEC.get(sid)
+    if spec is None:
+        return False
+    _, _, _, def_hm, _ = spec
+    enabled, eod_hm = resolve_strategy_eod_params(params, sid)
+    return is_backtest_eod_bar(candle_time, enabled, eod_hm, default_hm=def_hm)
diff --git a/kis_trader/engine/tail_engine.py b/kis_trader/engine/tail_engine.py
index 90e41b6..c69dc16 100644
--- a/kis_trader/engine/tail_engine.py
+++ b/kis_trader/engine/tail_engine.py
@@ -67,7 +67,8 @@ from kis_trader.engine.tail_tick_replay import (
     tail_timeframe_min,
     try_limit_fill_on_bar_with_ticks,
 )
-from kis_trader.strategies.base import is_strategy_eod_bar
+from kis_trader.engine.atr_series import compute_atr_series
+from kis_trader.engine.strategy_eod import is_strategy_eod_bar
 from kis_trader.engine.tail_env_keys import (
     tail_env_bool,
     tail_env_float,
@@ -374,36 +375,6 @@ def compute_sma_series(closes: List[float], period: int = 20) -> List[Optional[f
     return sma_list
 
 
-def compute_atr_series(candles: List[Dict], period: int = 14) -> List[Optional[float]]:
-    """
-    ATR(Average True Range) 변동성 지표 계산기 (엔진 내부용).
-
-    ■ RMA(Wilder's Smoothing) 방식 — TradingView 기본과 동일 (2026-06 SMA→RMA 전환).
-      ATR_t = (ATR_{t-1} × (period-1) + TR_t) / period
-      · 첫 ATR(인덱스 period)은 SMA(TR[1..period])로 시드.
-      · SMA 대비: 급락(큰 TR)이 14봉 지나도 '계단식 급락' 없이 완만히 감쇠 →
-        급변장에서 손절/목표가가 덜 출렁임.
-    """
-    atr_list: List[Optional[float]] = [None] * len(candles)
-    if len(candles) < period + 1:
-        return atr_list
-    trs = [0.0] * len(candles)
-    for i in range(1, len(candles)):
-        hi = float(candles[i]["high"])
-        lo = float(candles[i]["low"])
-        prev_cl = float(candles[i - 1]["close"])
-        trs[i] = max(hi - lo, abs(hi - prev_cl), abs(lo - prev_cl))
-
-    # 첫 ATR(인덱스 period): TR[1..period] 단순 평균으로 시드 (Wilder 초기값)
-    prev_atr = sum(trs[1:period + 1]) / period
-    atr_list[period] = prev_atr
-    # 이후: Wilder RMA 누적 감쇠 (이전 ATR×(n-1) + 오늘 TR) / n
-    for i in range(period + 1, len(candles)):
-        prev_atr = (prev_atr * (period - 1) + trs[i]) / period
-        atr_list[i] = prev_atr
-    return atr_list
-
-
 def _t2dt(t: str) -> datetime:
     """candle_time 문자열 → datetime."""
     return datetime.strptime(t, "%Y%m%d%H%M")
diff --git a/kis_trader/strategies/base.py b/kis_trader/strategies/base.py
index a446dad..7ee58b7 100644
--- a/kis_trader/strategies/base.py
+++ b/kis_trader/strategies/base.py
@@ -61,126 +61,13 @@ def _is_non_stock(name: str, code: str) -> bool:
     return False
 
 
-def parse_eod_hm(raw: str, default: str = "15:25") -> Tuple[int, int]:
-    """EOD 시각 문자열 → (시, 분). ``1515`` / ``15:15`` 모두 허용."""
-    s = str(raw or default).strip()
-    if not s or s.lower() == "none":
-        s = default
-    if ":" in s:
-        parts = s.split(":", 1)
-        try:
-            return int(parts[0]), int(parts[1])
-        except (ValueError, TypeError):
-            pass
-    if len(s) == 4 and s.isdigit():
-        return int(s[:2]), int(s[2:])
-    try:
-        hh, mm = [int(x) for x in s.split(":")]
-        return hh, mm
-    except Exception:
-        return 15, 25
-
-
-def is_live_eod_now(
-    enabled: bool,
-    eod_hm: str,
-    now: dt,
-    *,
-    default_hm: str = "15:25",
-) -> bool:
-    """실매 EOD 당일청산 시각 도달 여부."""
-    if not enabled:
-        return False
-    eod_hh, eod_mm = parse_eod_hm(eod_hm, default_hm)
-    return (now.hour > eod_hh) or (now.hour == eod_hh and now.minute >= eod_mm)
-
-
-# 전략별 EOD env 키 — 실매·백테·파라서치 공통
-_STRATEGY_EOD_SPEC: Dict[str, Tuple[str, str, bool, str, str]] = {
-    "BREAKOUT": ("BREAKOUT_EOD_ENABLED", "BREAKOUT_EOD_HM", True, "15:15", ""),
-    "MOMENTUM": ("MOMENTUM_EOD_ENABLED", "MOMENTUM_EOD_HM", True, "15:25", "MOMENTUM_FORCE_EOD_EXIT"),
-    "TAIL": ("TAIL_EOD_ENABLED", "TAIL_EOD_HM", True, "15:25", "force_eod_exit"),
-    "SHORT": ("TAIL_EOD_ENABLED", "TAIL_EOD_HM", True, "15:25", "force_eod_exit"),
-}
-
-
-def _params_truthy_bool(val: Any, default: bool) -> bool:
-    if val is None or val == "" or val == "None":
-        return default
-    if isinstance(val, bool):
-        return val
-    return str(val).strip().lower() in ("1", "true", "t", "y", "yes", "on")
-
-
-def resolve_strategy_eod_params(
-    params: Dict[str, Any],
-    strategy_id: str,
-) -> Tuple[bool, str]:
-    """params → (eod_enabled, eod_hm). UI ``eod_enabled``/``eod_hm`` 우선, 없으면 env 키."""
-    sid = str(strategy_id or "").strip().upper()
-    if sid == "SHORT":
-        sid = "TAIL"
-    spec = _STRATEGY_EOD_SPEC.get(sid)
-    if spec is None:
-        return False, "15:25"
-    en_key, hm_key, def_en, def_hm, leg_key = spec
-
-    if "eod_enabled" in params:
-        enabled = _params_truthy_bool(params.get("eod_enabled"), def_en)
-    elif en_key in params:
-        enabled = _params_truthy_bool(params.get(en_key), def_en)
-    elif leg_key and leg_key in params:
-        enabled = _params_truthy_bool(params.get(leg_key), def_en)
-    else:
-        enabled = def_en
-
-    raw_hm = params.get("eod_hm")
-    if raw_hm not in (None, "", "None"):
-        eod_hm = str(raw_hm).strip()
-    elif params.get(hm_key) not in (None, "", "None"):
-        eod_hm = str(params.get(hm_key)).strip()
-    else:
-        eod_hm = def_hm
-    return enabled, eod_hm
-
-
-def is_backtest_eod_bar(
-    candle_time: str,
-    enabled: bool,
-    eod_hm: str,
-    *,
-    default_hm: str = "15:25",
-) -> bool:
-    """백테 1분봉/스캔키 — 실매 ``is_live_eod_now`` 와 동일 시각 기준."""
-    if not enabled:
-        return False
-    eod_hh, eod_mm = parse_eod_hm(eod_hm, default_hm)
-    t = str(candle_time).strip()
-    if len(t) < 12:
-        return False
-    try:
-        bar_hh = int(t[8:10])
-        bar_mm = int(t[10:12])
-    except (ValueError, TypeError):
-        return False
-    return (bar_hh > eod_hh) or (bar_hh == eod_hh and bar_mm >= eod_mm)
-
-
-def is_strategy_eod_bar(
-    candle_time: str,
-    params: Dict[str, Any],
-    strategy_id: str,
-) -> bool:
-    """전략 params + 봉시각 → EOD 청산 여부 (실매와 동일 키·시각)."""
-    sid = str(strategy_id or "").strip().upper()
-    if sid == "SHORT":
-        sid = "TAIL"
-    spec = _STRATEGY_EOD_SPEC.get(sid)
-    if spec is None:
-        return False
-    _, _, _, def_hm, _ = spec
-    enabled, eod_hm = resolve_strategy_eod_params(params, sid)
-    return is_backtest_eod_bar(candle_time, enabled, eod_hm, default_hm=def_hm)
+from ..engine.strategy_eod import (
+    is_backtest_eod_bar,
+    is_live_eod_now,
+    is_strategy_eod_bar,
+    parse_eod_hm,
+    resolve_strategy_eod_params,
+)
 
 
 class BaseStrategy(ABC, threading.Thread):
diff --git a/kis_trader/strategies/breakout.py b/kis_trader/strategies/breakout.py
index 6099657..a480039 100644
--- a/kis_trader/strategies/breakout.py
+++ b/kis_trader/strategies/breakout.py
@@ -41,7 +41,7 @@ _bo_logger = get_logger("kis_trader.breakout")
 from ..utils.position_sizing import invest_qty_for_price
 from ..engine.ema_trend_filter import eval_ema_uptrend_reject
 from ..engine.scalping_engine import check_sell_signal_backtest_bar
-from ..engine.tail_engine import compute_atr_series
+from ..engine.atr_series import compute_atr_series
 from ..engine.whipsaw_filter import whipsaw_reject_for_signal
 from ..engine.orderbook_filter import orderbook_reject_for_entry
 from ..engine.program_filter import program_reject_for_entry