diff --git a/account.py b/account.py
index b68f18d39d..03c809146f 100644
--- a/account.py
+++ b/account.py
@@ -843,6 +843,7 @@ class Account(ModelSQL, ModelView):
             default = {}
         default['left'] = 0
         default['right'] = 0
+        default.setdefault('deferrals', [])
         new_accounts = super(Account, cls).copy(accounts, default=default)
         cls._rebuild_tree('parent', None, 0)
         return new_accounts