s 391 Accounting reference periods and accounting reference date
(1) A company's accounting reference periods are determined according to its accounting reference date in each calendar year. (2) The accounting reference date of a company incorporated in Great Britain before 1st April 1996 is— (a) the date specified by notice to the registrar in accordance with section 224(2) of the Companies Act 1985 (c. 6) (notice specifying accounting reference date given within nine months of incorporation), or (b) failing such notice— (i) in the case of a company incorporated before 1st April 1990, 31st March, and (ii) in the case of a company incorporated on or after 1st April 1990, the last day of the month in which the anniversary of its incorporation falls. (3) The accounting reference date of a company incorporated in Northern Ireland before 22nd August 1997 is— (a) the date specified by notice to the registrar in accordance with article 232(2) of the Companies (Northern Ireland) Order 1986 (S.I. 1986/1032 (N.I. 6)) (notice specifying accounting reference date given within nine months of incorporation), or (b) failing such notice— (i) in the case of a company incorporated before the coming into operation of Article 5 of the Companies (Northern Ireland) Order 1990 (S.I. 1990/593 (N.I. 5)), 31st March, and (ii) in the case of a company incorporated after the coming into operation of that Article, the last day of the month in which the anniversary of its incorporation falls. (4) The accounting reference date of a company incorporated— (a) in Great Britain on or after 1st April 1996 and before the commencement of this Act, (b) in Northern Ireland on or after 22nd August 1997 and before the commencement of this Act, or (c) after the commencement of this Act, is the last day of the month in which the anniversary of its incorporation falls. (5) A company's first accounting reference period is the period of more than six months, but not more than 18 months, beginning with the date of its incorporation and ending with its accounting reference date. (6) Its subsequent accounting reference periods are successive periods of twelve months beginning immediately after the end of the previous accounting reference period and ending with its accounting reference date. (7) This section has effect subject to the provisions of section 392 (alteration of accounting reference date).