diff --git a/app/models/submitter.rb b/app/models/submitter.rb
index c21da28f..b684dfbe 100644
--- a/app/models/submitter.rb
+++ b/app/models/submitter.rb
@@ -28,11 +28,12 @@
 #
 # Indexes
 #
-#  index_submitters_on_account_id_and_id  (account_id,id)
-#  index_submitters_on_email              (email)
-#  index_submitters_on_external_id        (external_id)
-#  index_submitters_on_slug               (slug) UNIQUE
-#  index_submitters_on_submission_id      (submission_id)
+#  index_submitters_on_account_id_and_id            (account_id,id)
+#  index_submitters_on_completed_at_and_account_id  (completed_at,account_id)
+#  index_submitters_on_email                        (email)
+#  index_submitters_on_external_id                  (external_id)
+#  index_submitters_on_slug                         (slug) UNIQUE
+#  index_submitters_on_submission_id                (submission_id)
 #
 # Foreign Keys
 #
diff --git a/db/migrate/20250615091654_add_submitters_completed_at_index.rb b/db/migrate/20250615091654_add_submitters_completed_at_index.rb
new file mode 100644
index 00000000..1ff3431f
--- /dev/null
+++ b/db/migrate/20250615091654_add_submitters_completed_at_index.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class AddSubmittersCompletedAtIndex < ActiveRecord::Migration[8.0]
+  def change
+    add_index :submitters, %i[completed_at account_id]
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index ce914e83..c9e47280 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.0].define(version: 2025_06_13_160132) do
+ActiveRecord::Schema[8.0].define(version: 2025_06_15_091654) do
   # These are extensions that must be enabled in order to support this database
   enable_extension "btree_gin"
   enable_extension "plpgsql"
@@ -331,6 +331,7 @@ ActiveRecord::Schema[8.0].define(version: 2025_06_13_160132) do
     t.datetime "declined_at"
     t.string "timezone"
     t.index ["account_id", "id"], name: "index_submitters_on_account_id_and_id"
+    t.index ["completed_at", "account_id"], name: "index_submitters_on_completed_at_and_account_id"
     t.index ["email"], name: "index_submitters_on_email"
     t.index ["external_id"], name: "index_submitters_on_external_id"
     t.index ["slug"], name: "index_submitters_on_slug", unique: true