diff --git a/src/merge_stats.py b/src/merge_stats.py
index 74a42e1a0ebaf32e619c27c19e20c446f8ad243b..38841a8eab028ac42d040d844b7dbd7c737a2785 100644
--- a/src/merge_stats.py
+++ b/src/merge_stats.py
@@ -12,7 +12,7 @@ def parse_json(path):
               type=click.Path(exists=True, dir_okay=False, readable=True),
               required=True,
               help="Path to vcfstats json")
-@click.option("collectstats",
+@click.argument("collectstats",
               type=click.Path(exists=True, dir_okay=False, readable=True),
               nargs=-1,
               required=True)