diff --git a/fairmq/shmem/Manager.h b/fairmq/shmem/Manager.h
index 5ace4c0f..9a41f332 100644
--- a/fairmq/shmem/Manager.h
+++ b/fairmq/shmem/Manager.h
@@ -88,6 +88,11 @@ struct ShmHeader
         return HdrPtr(ptr)->refCount;
     }
 
+    static uint16_t UserOffset(char* ptr)
+    {
+        return HdrPartSize() + HdrPtr(ptr)->userOffset;
+    }
+
     static char* UserPtr(char* ptr)
     {
         // [HdrOffset(uint16_t)][Hdr alignment][Hdr][user buffer alignment][user buffer]
diff --git a/fairmq/shmem/Message.h b/fairmq/shmem/Message.h
index 0e674e00..50d349bb 100644
--- a/fairmq/shmem/Message.h
+++ b/fairmq/shmem/Message.h
@@ -217,7 +217,9 @@ class Message final : public fair::mq::Message
         } else if (newSize <= fMeta.fSize) {
             try {
                 try {
-                    char* ptr = fManager.ShrinkInPlace(newSize, fManager.GetAddressFromHandle(fMeta.fHandle, fMeta.fSegmentId), fMeta.fSegmentId);
+                    char* oldPtr = fManager.GetAddressFromHandle(fMeta.fHandle, fMeta.fSegmentId);
+                    uint16_t userOffset = ShmHeader::UserOffset(oldPtr);
+                    char* ptr = fManager.ShrinkInPlace(userOffset + newSize, oldPtr, fMeta.fSegmentId);
                     fLocalPtr = ShmHeader::UserPtr(ptr);
                     fMeta.fSize = newSize;
                     return true;