diff --git a/UnitTestProject/Modules/SwapModule/Penalty/PenaltyBoundaryMatrixTest.cs b/UnitTestProject/Modules/SwapModule/Penalty/PenaltyBoundaryMatrixTest.cs
index 6ebb8bf0..bf3dd846 100644
--- a/UnitTestProject/Modules/SwapModule/Penalty/PenaltyBoundaryMatrixTest.cs
+++ b/UnitTestProject/Modules/SwapModule/Penalty/PenaltyBoundaryMatrixTest.cs
@@ -11,7 +11,9 @@ namespace UnitTestProject.Modules.SwapModule.Penalty
     ///   ② 重置日前一日平仓（② 几乎整段、窗口首段 0 天）；
     ///   ③ 到期日恰为重置日（末段 [到期,到期] 1 天）；
     ///   ④ 锚点偏离（td.StartDate=7/31 但腿 PosiStartDate=8/3 的延期/存续腿——重置网格整体不同）；
-    ///   ⑤ 起息日当天平仓（无 preEod）。
+    ///   ⑤ 起息日当天平仓（无 preEod）；
+    ///   ⑥ 部分平仓 share<1 + 无 preEod 兜底——钉 merger 复刻 GetInterests 本金口径的接缝
+    ///     （现有用例全部 closePercent=1m，重放基数与复刻本金的口径偏差在 share=1 下不可见）。
     ///
     /// 一致性前提（与现实世界对齐）：冻结利率 = 当前重置区间（含 unwind-1 的区间）的在役利率，
     /// 即"历史末段利率 = 冻结利率"；历史各段定盘不同（体现真实 FR007 利率历史）。
@@ -67,7 +69,7 @@ namespace UnitTestProject.Modules.SwapModule.Penalty
 
         private static decimal RunFee(trade td, swap_position p, decimal settledAmount,
             eod_swap_position? preEod, DateTime unwind, bool settled, decimal spread,
-            decimal interestPrincipal = 0m, bool maturityCalcLast = true)
+            decimal interestPrincipal = 0m, bool maturityCalcLast = true, decimal closePercent = 1m)
         {
             var e = new swap_flow_event
             {
@@ -78,7 +80,8 @@ namespace UnitTestProject.Modules.SwapModule.Penalty
             PenaltyInterestFeeMerger.Merge(
                 td, new List<swap_position> { p }, new List<swap_flow_event> { e },
                 unwind, AnnualDays, settled, maturityCalcLast: maturityCalcLast,
-                posiNotionalValue: Notional, closePosiNotionalValue: Notional, closePercent: 1m,
+                posiNotionalValue: Notional, closePosiNotionalValue: Notional * closePercent,
+                closePercent: closePercent,
                 getSpread: _ => spread, getPreEod: _ => preEod, tryGetFixing: (d, c) => spread);
             return e.InterestFee;
         }
@@ -192,6 +195,30 @@ namespace UnitTestProject.Modules.SwapModule.Penalty
                 "无preEod+已有重置：兜底取事件基数后 ① 精确，全期=实结+罚息（修复前差≈3.17元）");
         }
 
+        [TestMethod]
+        public void 部分平仓无preEod兜底_share对齐本金口径_恒等式成立()
+        {
+            // 接缝守卫：merger 的 closePrincipal 走 CalcNotional 复刻 GetInterests 口径
+            // （标的期初全价 = posiNotional×closePercent），而重放基数由调用方以
+            // closePosiNotionalValue 缩放——两处口径若有偏差，share=1 时不可见、
+            // share<1 时 ① 里会混入本金差。本用例以 50% 平仓钉死该对齐。
+            var start = new DateTime(2026, 8, 5); var unwind = new DateTime(2026, 8, 20); var maturity = new DateTime(2026, 9, 30);
+            var hist = new decimal[] { 0.0216m, 0.0144m }; // 8/5 段 2.16% / 8/19 段 1.44%(=冻结)，14 天重置
+            var share = 0.5m;
+            var closedNotional = Notional * share;
+            // 被平份额的实结与重放基数：复利对 notional 线性，直接按半额本金重放
+            var elapsed = AccrueOnGrid(start, unwind, AccrualBoundary.StartOnly, hist, notional: closedNotional, period: 14);
+            var replayFinalBasis = closedNotional + AccrueOnGrid(start, new DateTime(2026, 8, 18), AccrualBoundary.Both, hist, notional: closedNotional, period: 14);
+
+            var fee = RunFee(CreateTrade(start, maturity), CompoundLeg(start, maturity, hist[^1], periodDays: 14), elapsed,
+                preEod: null, unwind: unwind, settled: false, spread: hist[^1],
+                interestPrincipal: replayFinalBasis, maturityCalcLast: false, closePercent: share);
+
+            var full = AccrueOnGrid(start, maturity, AccrualBoundary.StartOnly, hist, notional: closedNotional, period: 14);
+            Assert.AreEqual((double)full, (double)(elapsed + fee), 0.01,
+                "部分平仓+无preEod：兜底①按被平份额缩放精确，全期(被平份额)=实结+罚息（口径漂移时此式必挂）");
+        }
+
         [TestMethod]
         public void 起息日当天平仓_无preEod_恒等式成立()
         {