diff --git a/options.c b/options.c
index e9df6a8..d0c53b6 100644
--- a/options.c
+++ b/options.c
@@ -2824,7 +2824,7 @@
 	{
 		.name	= "group_reporting",
 		.lname	= "Group reporting",
-		.type	= FIO_OPT_BOOL,
+		.type	= FIO_OPT_STR_SET,
 		.off1	= td_var_offset(group_reporting),
 		.help	= "Do reporting on a per-group basis",
 		.category = FIO_OPT_C_STAT,