18 CFR §367.4280

1. (a)This account must include the amortization of unamortized debt discount and expense on outstanding long-term debt. Amounts charged to this account must be credited concurrently to accounts 181, Unamortized debt expense (§ 367.1810), and 226, Unamortized discount on long-term debt—Debit (§ 367.2260).
2. (b)This account must be kept or supported so as to show the debt discount and expense on each class and series of long-term debt.