Fluctuations in the economy mean those looking for a luxury saloon can enjoy a buyers' market with most models having been reduced in price by more that £7,000, according to a study.
Research for Glass's Guide shows the cost of a one-year-old large luxury diesel saloon has fallen by 21% over the past year, or an average of £7,263.
Of all the larger saloons hit by the downturn, including the Audi A8, BMW 7 Series, Jaguar XJ and Mercedes S-Class, the Mercedes-Benz S320 CDI has suffered the most.
In November 2007, a one-year-old S320 CDI had an average trade value of £43,350. Identical models of the same age are now worth £33,250 - a 23% fall in value.
Richard Crosthwaite, prestige car editor at Glass's Guide, said: "A number of factors have combined to ravage the trade values of large luxury saloons and coupes.
"The economy has certainly made its mark, accelerating the trend where fleet buyers and consumers are gravitating towards smaller, cleaner and more fuel-efficient alternatives.
"A marked increase in supply within the used market has also hit values, particularly within the coupe segment where sales of new examples have hit record highs over recent years.
"Now seems to be the ideal time for prospective used-car buyers to consider picking up a former fat cat's executive express."
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