diff --git a/openapi.yaml b/openapi.yaml
index 0c3ca9fea..d334980dc 100644
--- a/openapi.yaml
+++ b/openapi.yaml
@@ -205,6 +205,7 @@ components:
       required:
         - id
         - totalRemainingCollateral
+        - freeSize
       allOf:
         - $ref: "#/components/schemas/SalesAvailability"
         - type: object