diff --git a/src/Decentralized.Domain/CoinPayment.cs b/src/Decentralized.Domain/CoinPayment.cs
index b49a1f5..a31ee99 100644
--- a/src/Decentralized.Domain/CoinPayment.cs
+++ b/src/Decentralized.Domain/CoinPayment.cs
@@ -33,11 +33,11 @@ namespace Decentralized.Domain
             }
         }
 
-        /// <summary>收款：返回收到的币数。heatPct 是物品的赃物热度（0–100）。</summary>
+        /// <summary>收款：返回收到的币数。heatPct 是物品的赃物热度（0–100）。多付的溢价是顾客给的额外收入，不带污点。</summary>
         public static double Receive(Wallet w, string asset, double credits, double price, double heatPct)
         {
             if (credits <= 0 || price <= 0) return 0;
-            double qty = credits / price;
+            double qty = credits * (1 + Tuning.CoinPayPremium) / price;   // 溢价只加在币数上，污点与成本仍按货值算
             w.Add(asset, qty);
             w.Taint += credits * Math.Max(0, Math.Min(100, heatPct)) / 100.0;
             w.Basis += credits;
diff --git a/src/Decentralized.Domain/Tuning.cs b/src/Decentralized.Domain/Tuning.cs
index 2f26d39..95f684f 100644
--- a/src/Decentralized.Domain/Tuning.cs
+++ b/src/Decentralized.Domain/Tuning.cs
@@ -65,6 +65,8 @@ namespace Decentralized.Domain
         public const int MixerMaxRounds = 5, MixerSanctionDays = 5;
         /// <summary>各派系顾客用币付款的概率。</summary>
         public const double CoinPayCrc = 0.30, CoinPayCrt = 0.50, CoinPayCra = 0.50, CoinPayPsc = 0.25;
+        /// <summary>用币付款的溢价：顾客多付的比例，补偿持币的污点与兑出的手续费。</summary>
+        public const double CoinPayPremium = 0.12;
         /// <summary>单个金融违规事件记入的罪证上限。</summary>
         public const double CrimeEventCap = 400;
 
diff --git a/tests/Decentralized.Domain.Tests/Program.cs b/tests/Decentralized.Domain.Tests/Program.cs
index 1a985a7..e8c3b05 100644
--- a/tests/Decentralized.Domain.Tests/Program.cs
+++ b/tests/Decentralized.Domain.Tests/Program.cs
@@ -493,8 +493,8 @@ internal static class Program
             var w = new Wallet { Address = "t" };
             Check(CoinPayment.AssetFor("FACTION_BLACK_MARKET") == Assets.CRT && CoinPayment.AssetFor("FACTION_SECURITY") == null, "派系对应的币");
             double q = CoinPayment.Receive(w, Assets.CRT, 200, 0.5, 40);
-            Check(Near(q, 400, 1e-9) && Near(w.Get(Assets.CRT), 400, 1e-9), "按币价换算数量");
-            Check(Near(w.Taint, 80, 1e-9) && Near(w.Basis, 200, 1e-9), "污点 = 货值 × 热度%，成本 = 货值");
+            Check(Near(q, 400 * (1 + Tuning.CoinPayPremium), 1e-9) && Near(w.Get(Assets.CRT), q, 1e-9), "按币价换算数量，含溢价");
+            Check(Near(w.Taint, 80, 1e-9) && Near(w.Basis, 200, 1e-9), "污点 = 货值 × 热度%，成本 = 货值（溢价不带污点）");
             Check(CoinPayment.Receive(w, Assets.CRC, 0, 1, 10) == 0, "零金额不收");
         });