diff --git a/src/E13.Common.Domain/IOwnable.cs b/src/E13.Common.Domain/IOwnable.cs
index 2af1aa5..3790192 100644
--- a/src/E13.Common.Domain/IOwnable.cs
+++ b/src/E13.Common.Domain/IOwnable.cs
@@ -4,9 +4,9 @@
 
 namespace E13.Common.Domain
 {
-    public interface IOwnable : IEntity
+    public interface IOwnable<T> : IEntity
     {
-        string OwnedBy { get; set; }
+        T OwnedBy { get; set; }
         string OwnedSource { get; set; }
         DateTime Owned { get; set; }
     }
diff --git a/test/E13.Common.Data.Db.Tests/Sample/TestOwnable.cs b/test/E13.Common.Data.Db.Tests/Sample/TestOwnable.cs
index d4794d6..d102748 100644
--- a/test/E13.Common.Data.Db.Tests/Sample/TestOwnable.cs
+++ b/test/E13.Common.Data.Db.Tests/Sample/TestOwnable.cs
@@ -7,7 +7,7 @@
 
 namespace E13.Common.Data.Db.Tests.Sample
 {
-    public class TestOwnable : IOwnable
+    public class TestOwnable : IOwnable<string>
     {
         public Guid Id { get; set; }
         public string OwnedBy { get; set; } = "OwnedBy";