diff --git a/src/table/settings/settings.ini b/src/table/settings/settings.ini
--- a/src/table/settings/settings.ini
+++ b/src/table/settings/settings.ini
@@ -232,6 +232,19 @@ strhelp  = STR_CONFIG_SETTING_SUBSIDY_MU
 strval   = STR_SUBSIDY_X1_5
 
 [SDT_VAR]
+var      = difficulty.subsidy_duration
+type     = SLE_UINT16
+from     = SLV_CUSTOM_SUBSIDY_DURATION
+flags    = SF_GUI_0_IS_SPECIAL
+def      = 1
+min      = 0
+max      = 5000
+interval = 1
+str      = STR_CONFIG_SETTING_SUBSIDY_DURATION
+strhelp  = STR_CONFIG_SETTING_SUBSIDY_DURATION_HELPTEXT
+strval   = STR_CONFIG_SETTING_SUBSIDY_DURATION_VALUE
+
+[SDT_VAR]
 var      = difficulty.construction_cost
 type     = SLE_UINT8
 from     = SLV_97