diff --git a/connect/models/schemas.py b/connect/models/schemas.py
index 78ff6c8..b9f542b 100644
--- a/connect/models/schemas.py
+++ b/connect/models/schemas.py
@@ -501,7 +501,7 @@ def make_object(self, data):
 
 class TierAccountsSchema(Schema):
     customer = fields.Nested(TierAccountSchema)
-    tier1 = fields.Nested(TierAccountSchema)
+    tier1 = fields.Nested(TierAccountSchema, allow_none=True)
     tier2 = fields.Nested(TierAccountSchema, allow_none=True)
 
     @post_load