diff --git a/CHANGELOG.md b/CHANGELOG.md
index fbacc9ba..c348e5a4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,6 @@
 Unreleased Changes
 ------------------
+* Issue - Fix the initializer for `NumericSetMarshaler`. (#163)
 
 2.15.2 (2026-08-17)
 ------------------
diff --git a/lib/aws-record/record/marshalers/numeric_set_marshaler.rb b/lib/aws-record/record/marshalers/numeric_set_marshaler.rb
index 9fe9e31a..8f874fcd 100644
--- a/lib/aws-record/record/marshalers/numeric_set_marshaler.rb
+++ b/lib/aws-record/record/marshalers/numeric_set_marshaler.rb
@@ -3,11 +3,11 @@
 module Aws
   module Record
     module Marshalers
-      def initialize(opts = {})
-        # pass
-      end
-
       class NumericSetMarshaler
+        def initialize(opts = {})
+          # pass
+        end
+
         def type_cast(raw_value)
           case raw_value
           when nil, ''
diff --git a/spec/aws-record/record/marshalers/numeric_set_marshaler_spec.rb b/spec/aws-record/record/marshalers/numeric_set_marshaler_spec.rb
index f6b46470..91c82c1b 100644
--- a/spec/aws-record/record/marshalers/numeric_set_marshaler_spec.rb
+++ b/spec/aws-record/record/marshalers/numeric_set_marshaler_spec.rb
@@ -57,6 +57,12 @@ module Marshalers
             end
           end
         end
+
+        context 'custom settings' do
+          it 'builds a marshaler' do
+            NumericSetMarshaler.new({})
+          end
+        end
       end
     end
   end
diff --git a/spec/aws-record/record/marshalers/string_set_marshaler_spec.rb b/spec/aws-record/record/marshalers/string_set_marshaler_spec.rb
index dfff0029..2778f346 100644
--- a/spec/aws-record/record/marshalers/string_set_marshaler_spec.rb
+++ b/spec/aws-record/record/marshalers/string_set_marshaler_spec.rb
@@ -57,6 +57,12 @@ module Marshalers
             end
           end
         end
+
+        context 'custom settings' do
+          it 'builds a marshaler' do
+            StringSetMarshaler.new({})
+          end
+        end
       end
     end
   end