diff --git a/pkgs/racket-doc/scribblings/reference/memory.scrbl b/pkgs/racket-doc/scribblings/reference/memory.scrbl
index bf529feca3..ccee0c33a4 100644
--- a/pkgs/racket-doc/scribblings/reference/memory.scrbl
+++ b/pkgs/racket-doc/scribblings/reference/memory.scrbl
@@ -224,7 +224,8 @@ with additional fields:
 
  @item{The @racket[pre-amount] field reports place-local memory use
       (i.e., not counting the memory use of child places) in bytes at
-      the time that the @tech{garbage collection} started.}
+      the time that the @tech{garbage collection} started. Additional
+      bytes registered via @racket[make-phantom-bytes] are included.}
 
  @item{The @racket[pre-admin-amount] is a larger number that includes
        memory use for the garbage collector's overhead, such as space
diff --git a/racket/src/racket/gc2/newgc.c b/racket/src/racket/gc2/newgc.c
index ebb3da8048..9c381792a7 100644
--- a/racket/src/racket/gc2/newgc.c
+++ b/racket/src/racket/gc2/newgc.c
@@ -4006,6 +4006,7 @@ void GC_dump_with_traces(int flags,
     GCWARN((GCOUTF,"Allocated (+reserved) page sizes: %" PRIdPTR " (+%" PRIdPTR ")\n",
             gc->used_pages * APAGE_SIZE,
             mmu_memory_allocated(gc->mmu) - (gc->used_pages * APAGE_SIZE)));
+    GCWARN((GCOUTF,"Phantom bytes: %" PRIdPTR "\n", gc->phantom_count));
     GCWARN((GCOUTF,"# of major collections: %" PRIdPTR "\n", gc->num_major_collects));
     GCWARN((GCOUTF,"# of minor collections: %" PRIdPTR "\n", gc->num_minor_collects));
     GCWARN((GCOUTF,"# of installed finalizers: %i\n", gc->num_fnls));
@@ -4946,7 +4947,7 @@ static void garbage_collect(NewGC *gc, int force_full, int no_full, int switchin
 
   old_mem_use = gc->memory_in_use;
   old_gen0    = gc->gen0.current_size;
-  old_mem_allocated = mmu_memory_allocated(gc->mmu);
+  old_mem_allocated = mmu_memory_allocated(gc->mmu) + gc->phantom_count;
 
   TIME_DECLS();
 
@@ -5166,7 +5167,7 @@ static void garbage_collect(NewGC *gc, int force_full, int no_full, int switchin
     park_for_inform_callback(gc);
     gc->GC_collect_inform_callback(is_master, gc->gc_full, 
                                    old_mem_use + old_gen0, gc->memory_in_use, 
-                                   old_mem_allocated, mmu_memory_allocated(gc->mmu),
+                                   old_mem_allocated, mmu_memory_allocated(gc->mmu)+gc->phantom_count,
                                    gc->child_gc_total);
     unpark_for_inform_callback(gc);
   }
@@ -5176,7 +5177,7 @@ static void garbage_collect(NewGC *gc, int force_full, int no_full, int switchin
     lmi->full = gc->gc_full,
     lmi->pre_used = old_mem_use + old_gen0;
     lmi->post_used = gc->memory_in_use;
-    lmi->pre_admin = old_mem_allocated;
+    lmi->pre_admin = old_mem_allocated+gc->phantom_count;
     lmi->post_admin = mmu_memory_allocated(gc->mmu);
   }
   GC_propagate_hierarchy_memory_use();