The FASB issued guidance to shorten the amortization period for certain purchased callable debt securities held at a premium to the earliest call date. Today, entities generally amortize the premium as a yield adjustment over the contractual life of the security. The guidance does not change the accounting for callable debt securities held at a discount. For public business entities, the guidance is effective for fiscal years beginning after 15 December 2018, and interim periods therein. For all other entities, it is effective for fiscal years beginning after 15 December 2019, and interim periods within fiscal years beginning after 15 December 2020. Early adoption is permitted, including in an interim period.