diff --git a/app/models/account.rb b/app/models/account.rb
index a2c144b8e..77e9285c5 100644
--- a/app/models/account.rb
+++ b/app/models/account.rb
@@ -95,9 +95,18 @@ class Account < ApplicationRecord
   delegated_type :accountable, types: Accountable::TYPES, dependent: :destroy
   delegate :subtype, to: :accountable, allow_nil: true
 
-  # Writer for subtype that delegates to the accountable
-  # This allows forms to set subtype directly on the account
+  # Writer for subtype that delegates to the accountable.
+  # This allows forms to set subtype directly on the account.
+  #
+  # On create the accountable may not be built yet: mass-assignment can apply
+  # `subtype` before `accountable_attributes` (which is what builds the
+  # accountable via accepts_nested_attributes_for). With no accountable in place
+  # `accountable&.subtype = value` is a silent no-op and the chosen subtype is
+  # dropped. Build the accountable from the delegated type first so the value is
+  # preserved; the later `accountable_attributes` assignment (update_only) then
+  # updates this same record instead of building a new one.
   def subtype=(value)
+    self.accountable = accountable_class.new if accountable.nil? && accountable_type.present?
     accountable&.subtype = value
   end
 
diff --git a/test/models/account_test.rb b/test/models/account_test.rb
index 0d7013354..373e1057e 100644
--- a/test/models/account_test.rb
+++ b/test/models/account_test.rb
@@ -99,6 +99,36 @@ class AccountTest < ActiveSupport::TestCase
     assert_equal opening_date, opening_anchor.entry.date
   end
 
+  test "subtype set as a top-level account attribute persists on create" do
+    Account.any_instance.stubs(:sync_later)
+
+    # Mirrors the create flow: the form submits `account[subtype]` as a
+    # top-level attribute (not nested under accountable_attributes). The
+    # accountable does not exist yet, so the delegating writer must build it.
+    account = Account.create_and_sync({
+      family: @family,
+      owner: @admin,
+      name: "Savings Account",
+      balance: 100,
+      currency: "USD",
+      accountable_type: "Depository",
+      subtype: "savings"
+    })
+
+    assert account.persisted?
+    assert_equal "savings", account.reload.subtype
+    assert_equal "savings", account.accountable.subtype
+  end
+
+  test "subtype assigned before accountable is built is not dropped" do
+    account = Account.new
+    account.accountable_type = "Depository"
+    account.subtype = "checking"
+
+    assert_not_nil account.accountable
+    assert_equal "checking", account.subtype
+  end
+
   test "accountable display names expose singular and group contexts" do
     assert_equal "Investment", Investment.singular_display_name
     assert_equal "Investments", Investment.display_name