diff --git a/lib/messaging/stream_name.rb b/lib/messaging/stream_name.rb
index <HASH>..<HASH> 100644
--- a/lib/messaging/stream_name.rb
+++ b/lib/messaging/stream_name.rb
@@ -17,7 +17,7 @@ module Messaging
       def category_macro(category)
         category = Casing::Camel.(category, symbol_to_string: true)
         self.send :define_method, :category do
-          @category || category
+          @category ||= category
         end
       end
       alias :category :category_macro
Category method is nil coalescing