Anthony Keith Parnes (born 1945) is an English ex-stockbroker, who was convicted and jailed with Ernest Saunders, Gerald Ronson, and Jack Lyons in the Guinness share-trading fraud of the 1980s; they collectively became known as "the Guinness Four". He was sentenced to two-and-a-half years on charges of false accounting and theft

The son of a London gown manufacturer, Parnes started his working life as an office boy with a stockbroker. Working in the Stock Exchange as a 'blue button' at A. J. Bekhore, he established a reputation for dealing with the big players of the fringe banking world. His colleagues nicknamed him "The Animal".

Parnes built up the strategic shareholding in Debenhams for Ronson and Sir Philip Harris during Burton's fiercely contested bid for the department store group. That stake helped win the bid for Sir Ralph Halpern, Burton's chairman, in a cliffhanging finish. The vote went in favour of Burton after the bid had been extended from the 3 pm Friday deadline to the following Sunday in a special dispensation by the Takeover Panel. After working at stockbrokers A.J. Bekhor, Rowe Rudd and McNally, he became a "half commission" man (that is, an introducing broker) with Alexander Laing and Cruickshank. As well as having dealt for various clients, Parnes' relations include the former chief executive of the major British jewellery company Ratners Group Gerald Ratner and the restaurateur and club-owner Richard Caring.