diff --git a/src/frontend/inpcom.c b/src/frontend/inpcom.c
index c03806f4c..69ae70171 100644
--- a/src/frontend/inpcom.c
+++ b/src/frontend/inpcom.c
@@ -2165,6 +2165,7 @@ inp_fix_subckt(struct names *subckt_w_params, char *s)
         /* beg  will point to start of param list   */
         beg = skip_back_ws_(equal, s);
         beg = skip_back_non_ws_(beg, s);
+        beg[-1] = '\0';         /* fixme can be < s */
 
         head = xx_new_line(NULL, NULL, 0, 0);
         /* create list of parameters that need to get sorted */