diff --git a/unmovable_map.h b/unmovable_map.h
index d8ee49a0b6..c34e6c5904 100644
--- a/unmovable_map.h
+++ b/unmovable_map.h
@@ -66,12 +66,13 @@ static inline byte GetCompanyHQSection(TileIndex t)
 
 static inline void EnlargeCompanyHQ(TileIndex t, byte size)
 {
+	size *= 4;
 	if (size <= _m[t].m5 - UNMOVABLE_HQ_NORTH) return;
 
-	_m[t + TileDiffXY(0, 0)].m5 = UNMOVABLE_HQ_NORTH + size * 4;
-	_m[t + TileDiffXY(0, 1)].m5 = UNMOVABLE_HQ_WEST  + size * 4;
-	_m[t + TileDiffXY(1, 0)].m5 = UNMOVABLE_HQ_EAST  + size * 4;
-	_m[t + TileDiffXY(1, 1)].m5 = UNMOVABLE_HQ_SOUTH + size * 4;
+	_m[t + TileDiffXY(0, 0)].m5 = UNMOVABLE_HQ_NORTH + size;
+	_m[t + TileDiffXY(0, 1)].m5 = UNMOVABLE_HQ_WEST  + size;
+	_m[t + TileDiffXY(1, 0)].m5 = UNMOVABLE_HQ_EAST  + size;
+	_m[t + TileDiffXY(1, 1)].m5 = UNMOVABLE_HQ_SOUTH + size;
 }