exemption certificate
noun[C]
TAXukusanofficialdocumentthat gives someonespecialpermissionnot to do orpaysomething:
amedical/taxexemptioncertificate
TheRevenueshould havediscretiontograntexemptioncertificatestobuildingsubcontractorswhere acompanyhasbecomeinsolventforbonafidereasons.