Assessee in default deemed liable for unpaid tax on accreted income; transferee liable only to asset's realizable extent. If a specified person fails to pay tax on accreted income, the principal officer or trustee and the specified person are deemed assessee in default and subject to all income-tax collection and recovery provisions. Where tax arises because assets were transferred, the transferee is deemed assessee in default for tax and interest but is liable only to the extent the received asset can meet that liability. The term specified person follows the definition in the related accrual-tax provision.