Interest on tax refunds: entitlement to simple monthly interest and additional annual interest where applicable Refunds of tax carry entitlement to simple monthly interest with commencement dates determined by the source of tax and by whether the return was filed within the due date; similar rules apply to refunds following application or section 140A payments, subject to a threshold exception. An additional annual interest applies to refunds arising from specified appellate or rectification orders for the post-time-limit period, excluding periods when proceedings are pending or refunds are withheld. Deductor refund claims attract monthly interest from claim or payment date. Periods of delay attributable to the assessee/deductor are excluded and Commissioner decisions on exclusions are final. Interest is adjusted where assessments change refundable amounts and excess interest is recoverable by demand.