diff --git a/DataFormats/Headers/include/Headers/Stack.h b/DataFormats/Headers/include/Headers/Stack.h
index 9770df9fa54ef..a7cd2624eb17d 100644
--- a/DataFormats/Headers/include/Headers/Stack.h
+++ b/DataFormats/Headers/include/Headers/Stack.h
@@ -38,7 +38,7 @@ struct Stack {
   struct freeobj {
     freeobj(memory_resource* mr, size_t s) : resource(mr), size(s) {}
     memory_resource* resource{nullptr};
-    size_t           size{0};
+    size_t size{0};
     void operator()(std::byte* ptr) { resource->deallocate(ptr, size, alignof(std::max_align_t)); }
   };