Section 73 - Determination of tax not paid or short paid or erroneously refunded or input tax credit wrongly availed or utilised for any reason other than fraud or any wilful- misstatement or suppression of facts.

Determination of unpaid tax: show-cause notice and assessment may lead to interest and penalty for nonpayment.

Determination for tax not paid, short paid, erroneously refunded or wrongly availed input tax credit (other than due to fraud or wilful suppression) is by service of a show cause notice requiring payment with interest and penalty; notices must be issued at least three months before the assessment time limit, supplemental statements may be served for related periods, voluntary pre-notice payment bars further notice for that amount, payment within thirty days of notice avoids penalty, the officer determines tax, interest and penalty and must issue an order within three years from the due date for the annual return or from the date of erroneous refund.