diff --git a/src/Compilers/CSharp/Portable/Symbols/Retargeting/RetargetingParameterSymbol.cs b/src/Compilers/CSharp/Portable/Symbols/Retargeting/RetargetingParameterSymbol.cs
index dd32f3e7212af..36b791724d1b6 100644
--- a/src/Compilers/CSharp/Portable/Symbols/Retargeting/RetargetingParameterSymbol.cs
+++ b/src/Compilers/CSharp/Portable/Symbols/Retargeting/RetargetingParameterSymbol.cs
@@ -5,6 +5,7 @@
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Diagnostics;
+using System.Threading;
 using Microsoft.CodeAnalysis.CSharp.Emit;
 
 namespace Microsoft.CodeAnalysis.CSharp.Symbols.Retargeting
@@ -23,6 +24,8 @@ internal abstract class RetargetingParameterSymbol : WrappedParameterSymbol
         /// </summary>
         private ImmutableArray<CSharpAttributeData> _lazyCustomAttributes;
 
+        private TypeWithAnnotations.Boxed? _lazyTypeWithAnnotations;
+
         protected RetargetingParameterSymbol(ParameterSymbol underlyingParameter)
             : base(underlyingParameter)
         {
@@ -38,7 +41,14 @@ public sealed override TypeWithAnnotations TypeWithAnnotations
         {
             get
             {
-                return this.RetargetingModule.RetargetingTranslator.Retarget(_underlyingParameter.TypeWithAnnotations, RetargetOptions.RetargetPrimitiveTypesByTypeCode);
+                if (_lazyTypeWithAnnotations is null)
+                {
+                    Interlocked.CompareExchange(ref _lazyTypeWithAnnotations,
+                        new TypeWithAnnotations.Boxed(this.RetargetingModule.RetargetingTranslator.Retarget(_underlyingParameter.TypeWithAnnotations, RetargetOptions.RetargetPrimitiveTypesByTypeCode)),
+                        null);
+                }
+
+                return _lazyTypeWithAnnotations.Value;
             }
         }