diff --git a/src/newgrf.cpp b/src/newgrf.cpp
--- a/src/newgrf.cpp
+++ b/src/newgrf.cpp
@@ -8389,7 +8389,8 @@ static void InitializeGRFSpecial()
 	                   |                                                      (1 << 0x1E)  // variablerunningcosts
 	                   |                                                      (1 << 0x1F); // any switch is on
 
-	_ttdpatch_flags[4] =                                                      (1 << 0x00); // larger persistent storage
+	_ttdpatch_flags[4] =                                                      (1 << 0x00)  // larger persistent storage
+	                   |             ((_settings_game.economy.inflation ? 1 : 0) << 0x01); // inflation is on
 }
 
 /** Reset and clear all NewGRF stations */