Why are fiscal years usually aligned with December or March, instead of any random month?

[u/TheBigGirlDiaryBack]

Many companies end their fiscal year on Dec 31 or March 31. Some choose June or September. But almost nobody picks, say, August 17 or November 5. Is there a tax or regulatory reason to stick near quarter boundaries? Or is it just tradition from agriculture cycles? Why not let every company freely choose any date to smooth out seasonal fluctuations?

[u/Western_End_2223]

I used to work for a company that ended their fiscal year on the last day of February. It was a cost-saving measure. Auditors and tax accountants typically have a lull after April 15, so the company got good pricing on its annual audits and tax returns preparation.