Fiscal year variants (FSV’s) are assigned to a company code via transaction OBY6. They determine the financial reporting periods of an entity e.g. 13 4-weekly periods, calendar months, 5-5-4 reporting etc.
During month end the current fiscal reporting period will be and the next month opened. Its possible to open and close specific ledgers e.g. AP, AR, GL and even sets of accounts within those ledgers. This way its possible to, for example, close all GL accounts and leave only the month end adjustment accounts open for posting.