diff --git a/src/System.Runtime.Extensions/ref/System.Runtime.Extensions.cs b/src/System.Runtime.Extensions/ref/System.Runtime.Extensions.cs
index 74fdf9090e6b..b9e4122fbc9e 100644
--- a/src/System.Runtime.Extensions/ref/System.Runtime.Extensions.cs
+++ b/src/System.Runtime.Extensions/ref/System.Runtime.Extensions.cs
@@ -1844,7 +1844,6 @@ public static class ProfileOptimization
 }
 namespace System.Runtime.CompilerServices
 {
-    [Serializable]
     public sealed class SwitchExpressionException : System.InvalidOperationException
     {
         public SwitchExpressionException() { }
diff --git a/src/System.Runtime.Extensions/src/Resources/Strings.resx b/src/System.Runtime.Extensions/src/Resources/Strings.resx
index 20981ccb5fc1..274bdd74054b 100644
--- a/src/System.Runtime.Extensions/src/Resources/Strings.resx
+++ b/src/System.Runtime.Extensions/src/Resources/Strings.resx
@@ -295,6 +295,9 @@
   <data name="PlatformNotSupported_Principal" xml:space="preserve">
     <value>Windows Principal functionality is not supported on this platform.</value>
   </data>
+  <data name="SwitchExpressionException_UnmatchedValue" xml:space="preserve">
+    <value>Unmatched value was {0}.</value>
+  </data>
   <data name="IO_PathTooLong_Path" xml:space="preserve">
     <value>The path '{0}' is too long, or a component of the specified path is too long.</value>
   </data>
diff --git a/src/System.Runtime.Extensions/src/System/Runtime/CompilerServices/SwitchExpressionException.cs b/src/System.Runtime.Extensions/src/System/Runtime/CompilerServices/SwitchExpressionException.cs
index f227cf3cfd4b..950b283b355d 100644
--- a/src/System.Runtime.Extensions/src/System/Runtime/CompilerServices/SwitchExpressionException.cs
+++ b/src/System.Runtime.Extensions/src/System/Runtime/CompilerServices/SwitchExpressionException.cs
@@ -13,29 +13,53 @@ namespace System.Runtime.CompilerServices
     /// </summary>
     [Serializable]
     [System.Runtime.CompilerServices.TypeForwardedFrom("mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089")]
-    public sealed class SwitchExpressionException : InvalidOperationException//, ISerializable
+    public sealed class SwitchExpressionException : InvalidOperationException
     {
         public SwitchExpressionException()
             : base(SR.Arg_SwitchExpressionException) { }
 
         public SwitchExpressionException(object unmatchedValue)
-            : base()
+            : this()
         {
             UnmatchedValue = unmatchedValue;
         }
 
-        private SwitchExpressionException(SerializationInfo info, StreamingContext context) 
+        private SwitchExpressionException(SerializationInfo info, StreamingContext context)
             : base(info, context)
         {
-            info.AddValue(nameof(UnmatchedValue), UnmatchedValue, typeof(object));
+            if (info == null)
+            {
+                throw new ArgumentNullException(nameof(info));
+            }
+            UnmatchedValue = info.GetValue(nameof(UnmatchedValue), typeof(object));
         }
 
         public object UnmatchedValue { get; }
 
         public override void GetObjectData(SerializationInfo info, StreamingContext context)
         {
-           base.GetObjectData(info, context);
+            base.GetObjectData(info, context);
+            if (info == null)
+            {
+                throw new ArgumentNullException(nameof(info));
+            }
             info.AddValue(nameof(UnmatchedValue), UnmatchedValue, typeof(object));
         }
+
+        public override string Message
+        {
+            get
+            {
+                string s = base.Message;
+                if (UnmatchedValue != null)
+                {
+                    string valueMessage = SR.Format(SR.SwitchExpressionException_UnmatchedValue, UnmatchedValue?.ToString());
+                    if (s == null)
+                        return valueMessage;
+                    return s + Environment.NewLine + valueMessage;
+                }
+                return s;
+            }
+        }
     }
 }
\ No newline at end of file
diff --git a/src/System.Runtime.Extensions/tests/System/Runtime/CompilerServices/SwitchExpressionExceptionTests.cs b/src/System.Runtime.Extensions/tests/System/Runtime/CompilerServices/SwitchExpressionExceptionTests.cs
index dff1c4cd982d..5bc035d5c931 100644
--- a/src/System.Runtime.Extensions/tests/System/Runtime/CompilerServices/SwitchExpressionExceptionTests.cs
+++ b/src/System.Runtime.Extensions/tests/System/Runtime/CompilerServices/SwitchExpressionExceptionTests.cs
@@ -24,7 +24,7 @@ public static void Constructor_StringAsObjectArg()
             var ex = new SwitchExpressionException(message);
 
             Assert.NotEqual(message, ex.Message);
-            Assert.Equal(message, ex.UnmatchedValue);
+            Assert.Same(message, ex.UnmatchedValue);
         }
 
         [Fact]
@@ -32,16 +32,23 @@ public void UnmatchedValue()
         {
             var ex = new SwitchExpressionException(34);
             Assert.Equal(34, ex.UnmatchedValue);
+            Assert.Contains(ex.UnmatchedValue.ToString(), ex.Message);
 
             var data = new byte[] { 1, 2, 3 };
             ex = new SwitchExpressionException(data);
-            Assert.Equal(data, ex.UnmatchedValue);
+            Assert.Same(data, ex.UnmatchedValue);
+            Assert.Contains(ex.UnmatchedValue.ToString(), ex.Message);
 
             ex = new SwitchExpressionException(true);
             Assert.Equal(true, ex.UnmatchedValue);
+            Assert.Contains(ex.UnmatchedValue.ToString(), ex.Message);
 
             ex = new SwitchExpressionException("34");
-            Assert.Equal("34", ex.UnmatchedValue);
+            Assert.Same("34", ex.UnmatchedValue);
+            Assert.Contains(ex.UnmatchedValue.ToString(), ex.Message);
+
+            ex = new SwitchExpressionException(null);
+            Assert.Null(ex.UnmatchedValue);
         }
     }
 }