diff --git a/zzio/EnumerableExtensions.cs b/zzio/EnumerableExtensions.cs
index 3a460f41..d77ef10d 100644
--- a/zzio/EnumerableExtensions.cs
+++ b/zzio/EnumerableExtensions.cs
@@ -26,7 +26,7 @@ public static int IndexOf<T>(this IEnumerable<T> set, Func<T, bool> predicate) =
 
     public static int IndexOf<T>(this IEnumerable<T> set, T value) => set
         .Indexed()
-        .Where(p => value?.Equals(p.Value) ?? false)
+        .Where(p => value?.Equals(p.Value) ?? ReferenceEquals(p.Value, null))
         .Select(prop => prop.Index)
         .Append(-1)
         .First();