diff --git a/src/company_cmd.cpp b/src/company_cmd.cpp
--- a/src/company_cmd.cpp
+++ b/src/company_cmd.cpp
@@ -112,6 +112,7 @@ void SetLocalCompany(CompanyID new_compa
 
 	/* ... and redraw the whole screen. */
 	MarkWholeScreenDirty();
+	InvalidateWindowClassesData(WC_SIGN_LIST, -1);
 }
 
 /**