Current U.S. GAAP mandates amortizing goodwill over no more than 40 years. Although many commentators suggest that 40 years is an arbitrary time span, there is a Biblical basis for 40-year amortization. The Bible refers to 40 years as the life of a generation. Since amortizing goodwill over no more than 40 years corresponds to amortizing it over no more than one generation of talented employees or customers, the process is not completely arbitrary.
"Biblical basis of forty-year goodwill amortization,"
Accounting Historians Journal: Vol. 27
, Article 8.
Available at: https://egrove.olemiss.edu/aah_journal/vol27/iss2/8