diff --git a/src/Microsoft.AspNet.Mvc.ModelBinding/Binders/MutableObjectModelBinder.cs b/src/Microsoft.AspNet.Mvc.ModelBinding/Binders/MutableObjectModelBinder.cs
index d329c85376..184a1e9805 100644
--- a/src/Microsoft.AspNet.Mvc.ModelBinding/Binders/MutableObjectModelBinder.cs
+++ b/src/Microsoft.AspNet.Mvc.ModelBinding/Binders/MutableObjectModelBinder.cs
@@ -18,7 +18,7 @@ namespace Microsoft.AspNet.Mvc.ModelBinding
         public virtual async Task<ModelBindingResult> BindModelAsync(ModelBindingContext bindingContext)
         {
             ModelBindingHelper.ValidateBindingContext(bindingContext);
-            if (!CanBindType(bindingContext.ModelType))
+            if (!CanBindType(bindingContext.ModelMetadata))
             {
                 return null;
             }
@@ -188,20 +188,20 @@ namespace Microsoft.AspNet.Mvc.ModelBinding
             return false;
         }
 
-        private static bool CanBindType(Type modelType)
+        private static bool CanBindType(ModelMetadata modelMetadata)
         {
             // Simple types cannot use this binder
-            var isComplexType = !TypeHelper.HasStringConverter(modelType);
-            if (!isComplexType)
+            if (!modelMetadata.IsComplexType)
             {
                 return false;
             }
 
-            if (modelType == typeof(ComplexModelDto))
+            if (modelMetadata.ModelType == typeof(ComplexModelDto))
             {
                 // forbidden type - will cause a stack overflow if we try binding this type
                 return false;
             }
+
             return true;
         }
 
diff --git a/src/Microsoft.AspNet.Mvc.ModelBinding/ModelMetadata.cs b/src/Microsoft.AspNet.Mvc.ModelBinding/ModelMetadata.cs
index 8fa258a340..6c4f03548e 100644
--- a/src/Microsoft.AspNet.Mvc.ModelBinding/ModelMetadata.cs
+++ b/src/Microsoft.AspNet.Mvc.ModelBinding/ModelMetadata.cs
@@ -13,6 +13,8 @@ namespace Microsoft.AspNet.Mvc.ModelBinding
     /// </summary>
     public abstract class ModelMetadata
     {
+        private bool? _isComplexType;
+
         /// <summary>
         /// The default value of <see cref="ModelMetadata.Order"/>.
         /// </summary>
@@ -254,7 +256,15 @@ namespace Microsoft.AspNet.Mvc.ModelBinding
         /// </remarks>
         public bool IsComplexType
         {
-            get { return !TypeHelper.HasStringConverter(ModelType); }
+            get
+            {
+                if (_isComplexType == null)
+                {
+                    _isComplexType = !TypeHelper.HasStringConverter(ModelType);
+                }
+
+                return _isComplexType.Value;
+            }
         }
 
         /// <summary>