Maintenance of accounts required; failure allows tax determination as if supplies occurred and audit obligations apply. Registered persons must keep accounts at their principal place of business recording production, inward and outward supplies, stock, input tax credit, output tax and other prescribed particulars; accounts for each registered business location may be maintained separately and electronically as prescribed. Storage operators and transporters must maintain consignor, consignee and goods details. The Commissioner may require or permit classes of persons to maintain additional or alternative accounts. Turnover threshold persons must obtain statutory audit and submit audited accounts and reconciliation. Failure to account permits the proper officer to determine tax on unaccounted supplies and apply tax determination procedures.