diff --git a/handler/lib/serde/nordigen.py b/handler/lib/serde/nordigen.py
index 327548c..94e95cf 100644
--- a/handler/lib/serde/nordigen.py
+++ b/handler/lib/serde/nordigen.py
@@ -7,7 +7,7 @@ class Amount(Model):
 
 
 class TransactionBBAN(Model):
-    bban: fields.Str()
+    bban: fields.Optional(fields.Str())
 
 
 class ExchangeInstructedAmount(Model):