diff --git a/etl/hubspot/hubspot_deal_differ.py b/etl/hubspot/hubspot_deal_differ.py
index 6a2203225..957955031 100644
--- a/etl/hubspot/hubspot_deal_differ.py
+++ b/etl/hubspot/hubspot_deal_differ.py
@@ -268,6 +268,12 @@ class HubspotDealDiffer:
             "third_party_surveyor_identifier": new_deal.get(
                 "third_party_surveyor_identifier"
             ),
+            # The Job Number OpenHousing returned on a successful log, if any.
+            # The consumer reads it to tell "job exists" (amend/abandon) from
+            # "never logged" (log).
+            "client_booking_reference": HubspotDealDiffer._client_booking_reference(
+                new_deal
+            ),
             # Carried for the abandon flow: it dates the cancel to the confirmed
             # survey date, falling back to the last submission date.
             "last_submission_date": (