diff --git a/src/clj/auto_ap/jobs/sales_summaries.clj b/src/clj/auto_ap/jobs/sales_summaries.clj
index ef68a69d..14251c0e 100644
--- a/src/clj/auto_ap/jobs/sales_summaries.clj
+++ b/src/clj/auto_ap/jobs/sales_summaries.clj
@@ -62,15 +62,24 @@
     {:ledger-mapped/ledger-side [:db/ident]}
     {:ledger-mapped/account [:db/id]}])
 
-(defn dirty-sales-summaries [c]
+(defn dirty-sales-summaries
+  "The client's dirty summaries, with enough of each item to evaluate and re-transact it.
+
+  `index-pull` returns a lazy seq running from `:start` to the END of the index, so this must
+  stop at the client boundary rather than filter: `:sales-summary/client+dirty` sorts by client
+  first, so every later client's summaries sit beyond this client's and filtering would walk all
+  of them — for every client — pulling their items on the way. That is quadratic in the number of
+  summaries, and it showed up as a full refresh degrading from ~180 client-days a minute to ~3 as
+  the summary count grew."
+  [c]
   (let [client-id (dc/entid (dc/db conn) c)]
     (->> (dc/index-pull  (dc/db conn)
                          {:index :avet
                           :selector (conj '[:sales-summary/date :sales-summary/client :db/id]
                                           {:sales-summary/items item-read})
                           :start [:sales-summary/client+dirty [client-id true]]})
-         (filter (fn [sales-summary]
-                   (= client-id (:db/id (:sales-summary/client sales-summary))))))))
+         (take-while (fn [sales-summary]
+                       (= client-id (:db/id (:sales-summary/client sales-summary))))))))
 
 (def default-days
   "How far back the scheduled refresh looks for summaries that still need recomputing."
diff --git a/test/clj/auto_ap/jobs/sales_summaries_test.clj b/test/clj/auto_ap/jobs/sales_summaries_test.clj
index 74b8b6dc..e81b4b50 100644
--- a/test/clj/auto_ap/jobs/sales_summaries_test.clj
+++ b/test/clj/auto_ap/jobs/sales_summaries_test.clj
@@ -120,3 +120,27 @@
                                  {:sales-order/external-id "ezcater/order/TEST-ezcater-vendorless"
                                   :sales-order/service-charge -75.0})])
       (is (nil? (service-charges-for test-client-id))))))
+
+(deftest dirty-summaries-stop-at-the-client-boundary
+  (testing "every dirty day for the client is returned, and none belonging to another client.
+
+           :sales-summary/client+dirty sorts by client, so an unbounded index scan would walk
+           every later client's summaries too — correct, but quadratic in the summary count."
+    (let [{:strs [test-client-id]} (setup-test-data [])
+          other (get-in @(dc/transact conn [{:db/id "other" :client/code (str "OTHER" (rand-int 100000))}])
+                        [:tempids "other"])
+          day (fn [client d dirty?]
+                {:sales-summary/client client
+                 :sales-summary/date d
+                 :sales-summary/dirty dirty?})]
+      @(dc/transact conn [(day test-client-id #inst "2026-08-01T07:00:00.000-00:00" true)
+                          (day test-client-id #inst "2026-08-02T07:00:00.000-00:00" true)
+                          (day test-client-id #inst "2026-08-03T07:00:00.000-00:00" false)
+                          (day other #inst "2026-08-01T07:00:00.000-00:00" true)
+                          (day other #inst "2026-08-02T07:00:00.000-00:00" true)])
+      (let [mine (sut/dirty-sales-summaries test-client-id)]
+        (is (= 2 (count mine)) "both dirty days, and not the clean one")
+        (is (every? #(= test-client-id (:db/id (:sales-summary/client %))) mine)
+            "and nothing belonging to the other client"))
+      (is (= 2 (count (sut/dirty-sales-summaries other)))
+          "the other client's own dirty days are still found"))))