diff --git a/app/controllers/form_controller.rb b/app/controllers/form_controller.rb
index ac5b46acf..eb58b656d 100644
--- a/app/controllers/form_controller.rb
+++ b/app/controllers/form_controller.rb
@@ -101,6 +101,14 @@ private
       else
         result[question.id] = question_params
       end
+
+      if current_user.support? && question.id == "owning_organisation_id" && @log.managing_organisation.blank?
+        owning_organisation = Organisation.find(result["owning_organisation_id"])
+        if owning_organisation&.managing_agents&.empty?
+          result["managing_organisation_id"] = owning_organisation.id
+        end
+      end
+
       result
     end
   end
diff --git a/spec/requests/form_controller_spec.rb b/spec/requests/form_controller_spec.rb
index a74ffb026..2d79746bc 100644
--- a/spec/requests/form_controller_spec.rb
+++ b/spec/requests/form_controller_spec.rb
@@ -136,6 +136,32 @@ RSpec.describe FormController, type: :request do
       end
     end
 
+    context "when owning organisation doesn't have any managing agents" do
+      let(:params) do
+        {
+          id: lettings_log.id,
+          lettings_log: {
+            page: "stock_owner",
+            owning_organisation_id: managing_organisation.id,
+          },
+        }
+      end
+
+      before do
+        lettings_log.update!(owning_organisation: nil, created_by: nil, managing_organisation: nil)
+        lettings_log.reload
+      end
+
+      it "sets managing organisation to owning organisation" do
+        post "/lettings-logs/#{lettings_log.id}/stock-owner", params: params
+        expect(response).to redirect_to("/lettings-logs/#{lettings_log.id}/created-by")
+        follow_redirect!
+        lettings_log.reload
+        expect(lettings_log.owning_organisation).to eq(managing_organisation)
+        expect(lettings_log.managing_organisation).to eq(managing_organisation)
+      end
+    end
+
     context "with valid managing organisation" do
       let(:params) do
         {