diff --git a/src/settings_gui.cpp b/src/settings_gui.cpp
--- a/src/settings_gui.cpp
+++ b/src/settings_gui.cpp
@@ -1691,6 +1691,7 @@ static SettingsContainer &GetSettingsTre
 			accounting->Add(new SettingEntry("difficulty.initial_interest"));
 			accounting->Add(new SettingEntry("difficulty.max_loan"));
 			accounting->Add(new SettingEntry("difficulty.subsidy_multiplier"));
+			accounting->Add(new SettingEntry("difficulty.subsidy_duration"));
 			accounting->Add(new SettingEntry("economy.feeder_payment_share"));
 			accounting->Add(new SettingEntry("economy.infrastructure_maintenance"));
 			accounting->Add(new SettingEntry("difficulty.vehicle_costs"));