diff --git a/app/models/account_activity.rb b/app/models/account_activity.rb
index c6523be33..3bc21a0d8 100644
--- a/app/models/account_activity.rb
+++ b/app/models/account_activity.rb
@@ -2,10 +2,10 @@ require 'csv'
 
 class AccountActivity < ActiveRecord::Base
   include Versions
-  belongs_to :account
+  belongs_to :account, required: true
   belongs_to :bank_transaction
   belongs_to :invoice
-
+  belongs_to :price, class_name: 'Billing::Price'
 
   CREATE = 'create'
   RENEW = 'renew'
diff --git a/app/models/billing/price.rb b/app/models/billing/price.rb
index c12cffffe..7924bbd6c 100644
--- a/app/models/billing/price.rb
+++ b/app/models/billing/price.rb
@@ -6,6 +6,7 @@ module Billing
     self.auto_html5_validation = false
 
     belongs_to :zone, class_name: 'DNS::Zone', required: true
+    has_many :account_activities
 
     validates :price, :valid_from, :operation_category, :duration, presence: true
     validates :operation_category, inclusion: { in: Proc.new { |price| price.class.operation_categories } }
diff --git a/spec/models/account_activity_spec.rb b/spec/models/account_activity_spec.rb
new file mode 100644
index 000000000..59e88c98b
--- /dev/null
+++ b/spec/models/account_activity_spec.rb
@@ -0,0 +1,13 @@
+require 'rails_helper'
+
+RSpec.describe AccountActivity do
+  describe 'account validation', db: false do
+    subject(:account_activity) { described_class.new }
+
+    it 'rejects absent' do
+      account_activity.account = nil
+      account_activity.validate
+      expect(account_activity.errors).to have_key(:account)
+    end
+  end
+end