No, I am not saying that. Section 197 does not deal with the period. It just "Defines" goodwill as an intangible asset that can be amortized.
Having said this, Private companies in the United States, however, may elect to amortize goodwill over a period of ten years or less under an accounting alternative from the Private Company Council of the FASB.
FASB - Financial Accounting Standard Board Statement 142 deals with this. You need not justify 5 years. You can choose anything between more than 1 to less than 10 years. FASB Accounting Standards Update No. 2014-02, Intangibles—Goodwill and Other (Topic 350) deals with this. It allows private companies to
use straight-line amortization of goodwill for up to ten years, or less if the company is able to demonstrate an alternative useful lifespan.
I am sure this would help.
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