diff --git a/Tracking/TrkTools/TrkAssociationTools/TrkAssociationTools/ATLAS_CHECK_THREAD_SAFETY b/Tracking/TrkTools/TrkAssociationTools/TrkAssociationTools/ATLAS_CHECK_THREAD_SAFETY
new file mode 100644
index 0000000000000000000000000000000000000000..bdea8aef2ad761386d21b0c1a7608b1d46744c62
--- /dev/null
+++ b/Tracking/TrkTools/TrkAssociationTools/TrkAssociationTools/ATLAS_CHECK_THREAD_SAFETY
@@ -0,0 +1 @@
+Tracking/TrkTools/TrkAssociationTools