diff --git a/openapi/paths/storefront/experimental@billing-portals@{slug}.yaml b/openapi/paths/storefront/experimental@billing-portals@{slug}.yaml
index 2f2e8dd1c9..18373b0ed8 100644
--- a/openapi/paths/storefront/experimental@billing-portals@{slug}.yaml
+++ b/openapi/paths/storefront/experimental@billing-portals@{slug}.yaml
@@ -18,6 +18,8 @@ get:
   security:
     - CustomerJWT: [ ]
   description: Retrieve a billing portal with a specified slug.
+  parameters:
+    - $ref: ../../components/parameters/collectionExpand.yaml
   responses:
     '200':
       description: Billing portal retrieved.