06 July 2012
It is a requirement of Indian GAAP under AS 14.
Excerpt as follows: 19. Goodwill arising on amalgamation represents a payment made in anticipation of future income and it is appropriate to treat it as an asset to be amortised to income on a systematic basis over its useful life. Due to the nature of goodwill, it is frequently difficult to estimate its useful life with reasonable certainty. Such estimation is, therefore, made on a prudent basis.
Accordingly, it is considered appropriate to amortise goodwill over a period not exceeding five years unless a somewhat longer period can be justified.