diff --git a/app/Transformers/TransactionGroupTransformer.php b/app/Transformers/TransactionGroupTransformer.php
index 5db09e28cb..bb8726ac8e 100644
--- a/app/Transformers/TransactionGroupTransformer.php
+++ b/app/Transformers/TransactionGroupTransformer.php
@@ -569,6 +569,6 @@ class TransactionGroupTransformer extends AbstractTransformer
             return null;
         }
 
-        return $object['interest_date']->toAtomString();
+        return $object[$key]->toAtomString();
     }
 }