diff --git a/lib/active_model/serializer/adapter/json_api.rb b/lib/active_model/serializer/adapter/json_api.rb
index 0671262ec..a7e0dedee 100644
--- a/lib/active_model/serializer/adapter/json_api.rb
+++ b/lib/active_model/serializer/adapter/json_api.rb
@@ -16,7 +16,7 @@ def initialize(serializer, options = {})
         end
 
         def serializable_hash(options = nil)
-          options = {}
+          options ||= {}
           if serializer.respond_to?(:each)
             serializer.each do |s|
               result = self.class.new(s, @options.merge(fieldset: @fieldset)).serializable_hash(options)