Stamp duty is a documentary tax and is paid (and evidenced) by the imposition of stamps on the face of instruments which effect transfers of stampable assets. The principal charge is on transfers on sale of stock and marketable securities, interests in certain partnerships and (where the conveyance or transfer is pursuant to a contract for the sale of land entered into on or before 10 July 2003) land. Stamp duty reserve tax (SDRT) is charged on agreements to transfer ‘chargeable securities’. In practice, the charge is usually encountered on transfers of UK stock and marketable securities.