diff --git a/negligent_octopus/core/forms.py b/negligent_octopus/core/forms.py
index 2262f36..ab1382c 100644
--- a/negligent_octopus/core/forms.py
+++ b/negligent_octopus/core/forms.py
@@ -1,36 +1,76 @@
 from django import forms
+from django.contrib.auth import get_user_model
 
 from .models import Account
 from .models import Transaction
 
 
-class AccountForm(forms.ModelForm):
+class BaseForm(forms.ModelForm):
+    def _override_field_queryset(self, field_name, model_class, filter_kwargs):
+        field = self.fields.get(field_name, None)
+        if field is not None:
+            field.queryset = model_class.objects.filter(**filter_kwargs)
+
+
+class AccountForm(BaseForm):
     owner = forms.ModelChoiceField(
         widget=forms.HiddenInput(),
         required=False,
-        queryset=None,
+        queryset=get_user_model().objects.none(),
         # WARNING: Set it in view. Prevents user from selecting something not his.
     )
 
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        instance = kwargs.get("instance", None)
+        if instance is not None:
+            self._override_field_queryset(
+                "owner",
+                get_user_model(),
+                {"pk": instance.owner.id},
+            )
+
     class Meta:
         model = Account
         fields = "__all__"  # noqa: DJ007
 
 
-class TransactionForm(forms.ModelForm):
+class TransactionForm(BaseForm):
     account = forms.ModelChoiceField(
-        queryset=None,
+        queryset=Account.objects.none(),
         # WARNING: Set it in view. Prevents user from selecting something not his.
     )
     destination_account = forms.ModelChoiceField(
-        queryset=None,
+        required=False,
+        queryset=Account.objects.none(),
         # WARNING: Set it in view. Prevents user from selecting something not his.
     )
     transfer_transaction = forms.ModelChoiceField(
-        queryset=None,
+        required=False,
+        queryset=Transaction.objects.none(),
         # WARNING: Set it in view. Prevents user from selecting something not his.
     )
 
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        instance = kwargs.get("instance", None)
+        if instance is not None:
+            self._override_field_queryset(
+                "account",
+                Account,
+                {"owner": instance.account.owner},
+            )
+            self._override_field_queryset(
+                "destination_account",
+                Account,
+                {"owner": instance.account.owner},
+            )
+            self._override_field_queryset(
+                "transfer_transaction",
+                Transaction,
+                {"account__owner": instance.account.owner},
+            )
+
     class Meta:
         model = Transaction
         fields = "__all__"  # noqa: DJ007