diff --git a/benchs/distributed_ondisk/merge_to_ondisk.py b/benchs/distributed_ondisk/merge_to_ondisk.py
index 70119b293a..735c92b2a2 100644
--- a/benchs/distributed_ondisk/merge_to_ondisk.py
+++ b/benchs/distributed_ondisk/merge_to_ondisk.py
@@ -1,3 +1,8 @@
+# Copyright (c) Facebook, Inc. and its affiliates.
+#
+# This source code is licensed under the MIT license found in the
+# LICENSE file in the root directory of this source tree.
+
 import os
 import faiss
 import argparse