diff --git a/addons/account/models/account.py b/addons/account/models/account.py
index fdaf8745619..81fee22bd30 100644
--- a/addons/account/models/account.py
+++ b/addons/account/models/account.py
@@ -454,7 +454,7 @@ class AccountAccount(models.Model):
         # This field should have been a char, but the aim is to use it in a side panel view with hierarchy, and it's only supported by many2one fields so far.
         # So instead, we make it a many2one to a psql view with what we need as records.
         for record in self:
-            record.root_id = (ord(record.code[0]) * 1000 + ord(record.code[1:2] or ' ')) if record.code else False
+            record.root_id = (ord(record.code[0]) * 1000 + ord(record.code[1:2] or '\x00')) if record.code else False
 
     @api.depends('code')
     def _compute_account_group(self):