diff --git a/kfet/views.py b/kfet/views.py
index f95fb2c6..7083d489 100644
--- a/kfet/views.py
+++ b/kfet/views.py
@@ -490,7 +490,8 @@ class AccountGroupUpdate(UpdateView):
 
 class AccountNegativeList(ListView):
     queryset = (AccountNegative.objects
-        .select_related('account', 'account__cofprofile__user'))
+        .select_related('account', 'account__cofprofile__user')
+        .exclude(account__trigramme='#13'))
     template_name = 'kfet/account_negative.html'
     context_object_name = 'negatives'
 
@@ -501,12 +502,13 @@ class AccountNegativeList(ListView):
             'overdraft_duration': Settings.OVERDRAFT_DURATION(),
         }
         negs_sum = (AccountNegative.objects
+            .exclude(account__trigramme='#13')
             .aggregate(
                 bal    = Coalesce(Sum('account__balance'),0),
                 offset = Coalesce(Sum('balance_offset'),0),
             )
         )
-        context['negatives_sum'] = negs_sum['bal'] + negs_sum['offset']
+        context['negatives_sum'] = negs_sum['bal'] - negs_sum['offset']
         return context
 
 # -----