
The Effective Interest Method, Explained: How Bond Discounts and Premiums Amortize Into Interest Expense
Interest expense equals carrying value times the market rate at issuance — the gap to the coupon amortizes the discount or premium each period.
#amortization
Amortizing intangible assets and deferred costs over their useful lives, including patents, Section 197 intangibles, and bond premiums

Interest expense equals carrying value times the market rate at issuance — the gap to the coupon amortizes the discount or premium each period.

ASC 350-40 capitalizes only application-development costs — configuration, interfaces, testing — and expenses preliminary, training, and data-migration costs.

ASU 2023-01 lets private companies use written, even unenforceable, terms for common-control leases and amortize improvements over useful life.

Impairment hits only when undiscounted cash flows fall short of carrying amount; the loss is book value minus fair value, and GAAP never reverses it.

Depreciation, amortization, prepaids, and accruals post monthly so each period carries its own costs — templates plus a quarterly review keep them honest.

Utility patents protect how an invention works for 20 years, design patents protect how it looks for 15, and plant patents cover asexually reproduced varieties.

Depreciation expenses tangibles minus salvage value; amortization writes off intangibles with none — and the IRS stretches acquired intangibles over 15 years.

A balloon loan amortizes over 30 years but matures in 5 to 7, leaving most principal due at once — refinance early or fund the lump sum deliberately.

Patent filing and legal fees are capitalized, not expensed — then amortized over the shorter of 20 years or useful life under Section 167.