diff --git a/Tracking/TrkVertexFitter/TrkV0Fitter/TrkV0Fitter/ATLAS_CHECK_THREAD_SAFETY b/Tracking/TrkVertexFitter/TrkV0Fitter/TrkV0Fitter/ATLAS_CHECK_THREAD_SAFETY
new file mode 100644
index 0000000000000000000000000000000000000000..daeac43fcef1c9151e46d2e1ae615a5301d5070f
--- /dev/null
+++ b/Tracking/TrkVertexFitter/TrkV0Fitter/TrkV0Fitter/ATLAS_CHECK_THREAD_SAFETY
@@ -0,0 +1 @@
+Tracking/TrkVertexFitter/TrkV0Fitter