diff --git a/builtin/repack.c b/builtin/repack.c
index f649379531..63585ad046 100644
--- a/builtin/repack.c
+++ b/builtin/repack.c
@@ -444,8 +444,10 @@ static void split_pack_geometry(struct pack_geometry *geometry, int factor)
 	geometry->split = split;
 }
 
-static struct packed_git *get_largest_active_pack(struct pack_geometry *geometry)
+static struct packed_git *get_preferred_pack(struct pack_geometry *geometry)
 {
+	uint32_t i;
+
 	if (!geometry) {
 		/*
 		 * No geometry means either an all-into-one repack (in which
@@ -460,7 +462,21 @@ static struct packed_git *get_largest_active_pack(struct pack_geometry *geometry
 	}
 	if (geometry->split == geometry->pack_nr)
 		return NULL;
-	return geometry->pack[geometry->pack_nr - 1];
+
+	/*
+	 * The preferred pack is the largest pack above the split line. In
+	 * other words, it is the largest pack that does not get rolled up in
+	 * the geometric repack.
+	 */
+	for (i = geometry->pack_nr; i > geometry->split; i--)
+		/*
+		 * A pack that is not local would never be included in a
+		 * multi-pack index. We thus skip over any non-local packs.
+		 */
+		if (geometry->pack[i - 1]->pack_local)
+			return geometry->pack[i - 1];
+
+	return NULL;
 }
 
 static void clear_pack_geometry(struct pack_geometry *geometry)
@@ -587,7 +603,7 @@ static int write_midx_included_packs(struct string_list *include,
 {
 	struct child_process cmd = CHILD_PROCESS_INIT;
 	struct string_list_item *item;
-	struct packed_git *largest = get_largest_active_pack(geometry);
+	struct packed_git *preferred = get_preferred_pack(geometry);
 	FILE *in;
 	int ret;
 
@@ -608,9 +624,9 @@ static int write_midx_included_packs(struct string_list *include,
 	if (write_bitmaps)
 		strvec_push(&cmd.args, "--bitmap");
 
-	if (largest)
+	if (preferred)
 		strvec_pushf(&cmd.args, "--preferred-pack=%s",
-			     pack_basename(largest));
+			     pack_basename(preferred));
 
 	if (refs_snapshot)
 		strvec_pushf(&cmd.args, "--refs-snapshot=%s", refs_snapshot);
diff --git a/t/t7703-repack-geometric.sh b/t/t7703-repack-geometric.sh
index 8821fbd2dd..4abc7d4c55 100755
--- a/t/t7703-repack-geometric.sh
+++ b/t/t7703-repack-geometric.sh
@@ -281,4 +281,36 @@ test_expect_success '--geometric with pack.packSizeLimit' '
 	)
 '
 
+test_expect_success '--geometric --write-midx with packfiles in main and alternate ODB' '
+	test_when_finished "rm -fr shared member" &&
+
+	# Create a shared repository that will serve as the alternate object
+	# database for the member linked to it. It has got some objects on its
+	# own that are packed into a single packfile.
+	git init shared &&
+	test_commit -C shared common-object &&
+	git -C shared repack -ad &&
+
+	# We create member so that its alternates file points to the shared
+	# repository. We then create a commit in it so that git-repack(1) has
+	# something to repack.
+	# of the shared object database.
+	git clone --shared shared member &&
+	test_commit -C member unique-object &&
+	git -C member repack --geometric=2 --write-midx 2>err &&
+	test_must_be_empty err &&
+
+	# We should see that a new packfile was generated.
+	find shared/.git/objects/pack -type f -name "*.pack" >packs &&
+	test_line_count = 1 packs &&
+
+	# We should also see a multi-pack-index. This multi-pack-index should
+	# never refer to any packfiles in the alternate object database.
+	test_path_is_file member/.git/objects/pack/multi-pack-index &&
+	test-tool read-midx member/.git/objects >packs.midx &&
+	grep "^pack-.*\.idx$" packs.midx | sort >actual &&
+	basename member/.git/objects/pack/pack-*.idx >expect &&
+	test_cmp expect actual
+'
+
 test_done