diff --git a/BTCPayServer.Tests/RateRulesTest.cs b/BTCPayServer.Tests/RateRulesTest.cs
index 2d3ce1446..53e89f842 100644
--- a/BTCPayServer.Tests/RateRulesTest.cs
+++ b/BTCPayServer.Tests/RateRulesTest.cs
@@ -4,6 +4,7 @@ using System.Collections.Generic;
 using System.Text;
 using BTCPayServer.Rating;
 using Xunit;
+using System.Globalization;
 
 namespace BTCPayServer.Tests
 {
@@ -127,7 +128,7 @@ namespace BTCPayServer.Tests
             rule2.ExchangeRates.SetRate("coinbase", CurrencyPair.Parse("BTC_CAD"), new BidAsk(1000m));
             Assert.True(rule2.Reevaluate());
             Assert.Equal("(1 / (2000 * (-3 + 1000 + 50 - 5))) * 1.1", rule2.ToString(true));
-            Assert.Equal(( 1.0m / (2000m * (-3m + 1000m + 50m - 5m))) * 1.1m, rule2.Value.Value);
+            Assert.Equal((1.0m / (2000m * (-3m + 1000m + 50m - 5m))) * 1.1m, rule2.Value.Value);
             ////////
 
             // Make sure kraken is not converted to CurrencyPair
@@ -151,7 +152,7 @@ namespace BTCPayServer.Tests
             rule2.ExchangeRates.SetRate("kraken", CurrencyPair.Parse("BTC_USD"), new BidAsk(6000m, 6100m));
             Assert.True(rule2.Reevaluate());
             Assert.Equal("1 / (6000, 6100)", rule2.ToString(true));
-            Assert.Equal(1m/6100m, rule2.Value.Value);
+            Assert.Equal(1m / 6100m, rule2.Value.Value);
 
             // Make sure the inverse has more priority than X_X or CDNT_X
             builder = new StringBuilder();
@@ -164,6 +165,15 @@ namespace BTCPayServer.Tests
             rule2.ExchangeRates.SetRate("coinaverage", CurrencyPair.Parse("BTC_USD"), new BidAsk(6000m, 6100m));
             Assert.True(rule2.Reevaluate());
             Assert.Equal("1 / 10", rule2.ToString(false));
+
+            // Make sure an inverse can be solved on an exchange
+            builder = new StringBuilder();
+            builder.AppendLine("X_X = coinaverage(X_X);");
+            Assert.True(RateRules.TryParse(builder.ToString(), out rules));
+            rule2 = rules.GetRuleFor(CurrencyPair.Parse("USD_BTC"));
+            rule2.ExchangeRates.SetRate("coinaverage", CurrencyPair.Parse("BTC_USD"), new BidAsk(6000m, 6100m));
+            Assert.True(rule2.Reevaluate());
+            Assert.Equal($"({(1m / 6100m).ToString(CultureInfo.InvariantCulture)}, {(1m / 6000m).ToString(CultureInfo.InvariantCulture)})", rule2.ToString(true));
         }
     }
 }
diff --git a/BTCPayServer/Rating/ExchangeRates.cs b/BTCPayServer/Rating/ExchangeRates.cs
index 81eb92e35..67531c931 100644
--- a/BTCPayServer/Rating/ExchangeRates.cs
+++ b/BTCPayServer/Rating/ExchangeRates.cs
@@ -63,8 +63,16 @@ namespace BTCPayServer.Rating
             if (ByExchange.TryGetValue(exchangeName, out var rates))
             {
                 var rate = rates.FirstOrDefault(r => r.CurrencyPair == currencyPair);
-                if (rate != null)
+                if(rate != null)
+                {
                     rate.BidAsk = bidAsk;
+                }
+                var invPair = currencyPair.Inverse();
+                var invRate = rates.FirstOrDefault(r => r.CurrencyPair == invPair);
+                if (invRate != null)
+                {
+                    invRate.BidAsk = bidAsk?.Inverse();
+                }
             }
         }
         public BidAsk GetRate(string exchangeName, CurrencyPair currencyPair)
@@ -135,7 +143,7 @@ namespace BTCPayServer.Rating
             return new BidAsk(1.0m / Ask, 1.0m / Bid);
         }
 
-        public static BidAsk operator+(BidAsk a, BidAsk b)
+        public static BidAsk operator +(BidAsk a, BidAsk b)
         {
             return new BidAsk(a.Bid + b.Bid, a.Ask + b.Ask);
         }
@@ -169,7 +177,7 @@ namespace BTCPayServer.Rating
             return new BidAsk(a.Bid / b.Ask, a.Ask / b.Bid);
         }
 
-        public static BidAsk operator-(BidAsk a, BidAsk b)
+        public static BidAsk operator -(BidAsk a, BidAsk b)
         {
             return new BidAsk(a.Bid - b.Bid, a.Ask - b.Ask);
         }