diff --git a/src/industry_cmd.cpp b/src/industry_cmd.cpp
index 6e93dd5a36..d1c2156247 100644
--- a/src/industry_cmd.cpp
+++ b/src/industry_cmd.cpp
@@ -1705,7 +1705,7 @@ CommandCost CmdBuildIndustry(TileIndex tile, DoCommandFlag flags, uint32 p1, uin
 }
 
 
-Industry *CreateNewIndustry(TileIndex tile, IndustryType type)
+static Industry *CreateNewIndustry(TileIndex tile, IndustryType type)
 {
 	const IndustrySpec *indspec = GetIndustrySpec(type);