diff --git a/Tracking/Acts/ActsTrkFinding/python/ActsSeedingToolConfig.py b/Tracking/Acts/ActsTrkFinding/python/ActsSeedingToolConfig.py
index 16ee1cf31e3acba67e70ddc775d24d1319d89c2f..151cc8442c4231ae12760890288e73df55e18038 100644
--- a/Tracking/Acts/ActsTrkFinding/python/ActsSeedingToolConfig.py
+++ b/Tracking/Acts/ActsTrkFinding/python/ActsSeedingToolConfig.py
@@ -65,6 +65,8 @@ def ActsSeedingToolBaseCfg(ConfigFlags,
     options.setdefault('radLengthPerSeed', 0.5)
     options.setdefault('minPt', 500. * UnitConstants.MeV)
     options.setdefault('impactMax', 3 * UnitConstants.mm)
+    options.setdefault('zBinNeighborsTop', [])
+    options.setdefault('zBinNeighborsBottom', [])
     
     ActsTrk__ActsSeedingTool = CompFactory.getComp("ActsTrk::ActsSeedingTool")
     acc.setPrivateTools(ActsTrk__ActsSeedingTool(**options))