diff --git a/modules/backend/src/main/scala/docspell/backend/item/Merge.scala b/modules/backend/src/main/scala/docspell/backend/item/Merge.scala
index 12d27a28..54a280d7 100644
--- a/modules/backend/src/main/scala/docspell/backend/item/Merge.scala
+++ b/modules/backend/src/main/scala/docspell/backend/item/Merge.scala
@@ -81,11 +81,12 @@ object Merge {
       def moveAttachments(items: NonEmptyList[Ident]): F[Int] = {
         val target = items.head
         for {
+          nextPos <- store.transact(RAttachment.nextPosition(target))
           attachs <- store.transact(items.tail.traverse(id => RAttachment.findByItem(id)))
           attachFlat = attachs.flatMap(_.toList)
-          n <- attachFlat.traverse(a =>
-            store.transact(RAttachment.updateItemId(a.id, target))
-          )
+          n <- attachFlat.zipWithIndex.traverse({ case (a, idx) =>
+            store.transact(RAttachment.updateItemId(a.id, target, nextPos + idx))
+          })
         } yield n.sum
       }
 
diff --git a/modules/store/src/main/scala/docspell/store/records/RAttachment.scala b/modules/store/src/main/scala/docspell/store/records/RAttachment.scala
index f08ff74f..061bb7b7 100644
--- a/modules/store/src/main/scala/docspell/store/records/RAttachment.scala
+++ b/modules/store/src/main/scala/docspell/store/records/RAttachment.scala
@@ -69,9 +69,9 @@ object RAttachment {
       DML.set(T.position.increment(1))
     )
 
-  def nextPosition(id: Ident): ConnectionIO[Int] =
+  def nextPosition(itemId: Ident): ConnectionIO[Int] =
     for {
-      max <- Select(max(T.position).s, from(T), T.itemId === id).build
+      max <- Select(max(T.position).s, from(T), T.itemId === itemId).build
         .query[Option[Int]]
         .unique
     } yield max.map(_ + 1).getOrElse(0)
@@ -97,8 +97,15 @@ object RAttachment {
       DML.set(T.fileId.setTo(fId))
     )
 
-  def updateItemId(attachId: Ident, itemId: Ident): ConnectionIO[Int] =
-    DML.update(T, T.id === attachId, DML.set(T.itemId.setTo(itemId)))
+  def updateItemId(attachId: Ident, itemId: Ident, pos: Int): ConnectionIO[Int] =
+    DML.update(
+      T,
+      T.id === attachId,
+      DML.set(
+        T.itemId.setTo(itemId),
+        T.position.setTo(pos)
+      )
+    )
 
   def updatePosition(attachId: Ident, pos: Int): ConnectionIO[Int] =
     DML.update(T, T.id === attachId, DML.set(T.position.setTo(pos)))