diff --git a/src/rule.c b/src/rule.c
index c67fa847..da2934e6 100644
--- a/src/rule.c
+++ b/src/rule.c
@@ -38,8 +38,8 @@ void rule_serialize(FILE *rsp, struct rule *rule, int index)
             escaped_title ? escaped_title : title ? title : "",
             rule->role ? rule->role : "",
             rule->subrole ? rule->subrole : "",
-            display_manager_display_id_arrangement(rule->effects.did),
-            space_manager_mission_control_index(rule->effects.sid),
+            rule->effects.did ? display_manager_display_id_arrangement(rule->effects.did) : 0,
+            rule->effects.sid ? space_manager_mission_control_index(rule->effects.sid) : 0,
             json_bool(rule_effects_check_flag(&rule->effects, RULE_FOLLOW_SPACE)),
             rule->effects.opacity,
             json_optional_bool(rule->effects.manage),