diff --git a/src/auditor/taler-auditor.c b/src/auditor/taler-auditor.c
index 0834d1dc5..6e4c76a9e 100644
--- a/src/auditor/taler-auditor.c
+++ b/src/auditor/taler-auditor.c
@@ -1116,6 +1116,8 @@ handle_reserve_out (void *cls,
   struct GNUNET_TIME_Absolute expire_withdraw;
   enum GNUNET_DB_QueryStatus qs;
 
+  (void) denom_sig; /* FIXME: checked elsewhere? If so, potential for
+                       optimization to simply not fetch this value from DB! */
   /* should be monotonically increasing */
   GNUNET_assert (rowid >= ppr.last_reserve_out_serial_id);
   ppr.last_reserve_out_serial_id = rowid + 1;