diff --git a/src/Numerics/Threading/CommonParallel.cs b/src/Numerics/Threading/CommonParallel.cs
index 1b777120..fa37fb0f 100644
--- a/src/Numerics/Threading/CommonParallel.cs
+++ b/src/Numerics/Threading/CommonParallel.cs
@@ -45,7 +45,7 @@ namespace MathNet.Numerics.Threading
     /// <summary>
     /// Used to simplify parallel code, particularly between the .NET 4.0 and Silverlight Code.
     /// </summary>
-    public static class CommonParallel
+    internal static class CommonParallel
     {
         private static ParallelOptions CreateParallelOptions()
         {