HRS §237-11
Which 12-month period your tax return covers
This section sets the tax year. Normally, it ends on December 31. If you keep your books on a different 12-month period, you may use that period for your tax return if the tax department agrees, and you must use it if the department tells you to.
businesses
The statute, as written — Tax year
The assessment of taxes herein made and the returns required therefor shall be for the year ending on December 31. If the taxpayer, in exercising a privilege taxable under this chapter, keeps the taxpayer's books reflecting the same on a basis other than the calendar year, the taxpayer may, with the assent of the department of taxation, and upon the direction of the department shall, make the taxpayer's annual returns and pay taxes for the year covering the taxpayer's accounting period as shown by the method of keeping the taxpayer's books.
LawTrove is not legal advice. The summary above is a computer-generated restatement — the authoritative text is the official version linked above.