A financial year is the twelve-month period that a UK company or the government uses for accounting purposes and preparing financial statements. The financial year may or may not be the same as a calendar year. The default accounting reference date (being the financial year end) is the last day of the month in which the company was incorporated, for example if you incorporated a company on 11 January, the accounting reference date would be 31 January. However, this can be shortened or lengthened to align with the calendar year or the tax or other group companies, as required.