Barter transactions do not alter the fair market value of assets. They are designed to recover value as the barter portion of the transaction is completed.
Authoritative accounting guidance in the United States for corporate-barter or trade-credit transactions is established within Emerging Issues Task Force Abstract 93-11 (EITF 93-11) and Accounting Principle Board Opinion No. 29 (APB 29). Please see the links for accounting practices and sample entries related to corporate barter.