Record retention obligations: registered persons must retain GST accounts for a prescribed period, extended during appeals or investigations. Registered persons must retain books of account and other records for seventy two months from the due date of furnishing the annual return for the year to which the records pertain. If the person is party to an appeal, revision, other proceedings before appellate or revisional authorities or tribunals, or is under investigation for an offence under Chapter XIX, records relating to the subject matter must be retained for one year after final disposal of that matter or for the seventy two month period, whichever is later.