A 1930s Mercedes may sell for more than US$16 million (NZ$19.8m) in California this month as classic-car auctioneers test the market with an unprecedented line-up of big-ticket cars by names such as Ferrari, Bugatti and Bentley.
The Mercedes-Benz 540 K Special Roadster is one of only 30 built. It may exceed the world auction record of US$16.4 million, set by a Ferrari last year, and comfortably beat the price of a Ferrari 250 GT California Spyder convertible, one of three included in the series of sales, which is estimated at US$9m.
While the Roadster seems set to become the most expensive car ever sold at auction, it has some way to go to beating the highest price ever paid for a car. That was reportedly set earlier this year when a 1962 Ferrari 250 GTO made for race driver Stirling Moss sold in a private transaction for $US35 million (NZ$45.9m).
''I've never seen so many expensive cars come up for auction at one time,'' says Tom Hartley Jnr, a UK-based classic car dealer.
''A lot of the major collectors of the last 30 years are getting old and other owners have seen prices rise and want to cash in. What happens this month is going to say a lot about the market.''
The summer sales held by Gooding & Co, RM Auctions and Bonhams on the US west coast are bellwether events for the market.
The Historic Automobile Group International (HAGI) Top 50 benchmark Index of exceptional classic cars has gained 8.2 per cent in the year to July. If this continues, it will be up about 14.4 per cent over 2012.
''Dealers across the board are saying that it is currently very difficult to get hold of quality cars,'' says Dietrich Hatlapa, founder of HAGI, a London-based research company.
''Owners are happy with what they have and would only sell if they find something else to buy with the money.''
Gooding's sale of 122 cars at Pebble Beach on August 18-19 is headed by the 1936 Mercedes with ''high-door, long-tail'' styling.
Another example of this rare model fetched US$9.7m for RM in Monterey last year.
At Gooding last year, a 1957 Ferrari 250 Testa Rossa set a record for any car at auction.
Gooding has valued a 1935 Duesenberg Model JN Convertible Coupe formerly owned by the Hollywood star Clark Gable at more than US$9m, while a 1931 Bentley 4.5-litre ''Blower'' Boat Tail is estimated at US$8m to US$10m.
On June 29, Bonhams sold a 1929 4.5-litre supercharged ''Blower'' Bentley in Sussex, southern England, for 5 million (NZ$9.7m), a record for any British model at auction.
''There aren't the speculators around as there were in the 1980s,'' the Connecticut-based dealer Thomas Hamann says.
''Today's buyers are looking for a sound investment. Ferraris from the 1950s and 1960s have seen the strongest rises. High prices are being paid for pre-war Bentleys. Less exceptional cars from that period might not see as much interest.''
The Ferrari 250 GT California Spyders include a 1960 example at Gooding. It is one of only nine alloy-bodied long wheelbase versions made and was owned by the late New England collector Sherman M Wolf since 1979.
''This will attract a lot of interest and could make $10 million,'' said Hamann, who specialises in classic Ferraris.
RM will offer a 1962 short wheelbase California Spyder at its Monterey auction of 120 automobiles on August 17-18.
Shown at the 1990 Pebble Beach Concours d'Elegance, this restored V-12 convertible carries an estimate of US$7.5 million to $US9 million. Ferrari made about 100 California Spyders from 1958 to 1963.
A 1997 GTC Gulf Team Davidoff McLaren F1 GTR racer is the most valuable lot in the Bonhams auction at Quail Lodge, Carmel, on August 16-17. Driven by works team members during the 1997 FIA GT championship at circuits such as the Nurburgring and Spa- Francorchamps, this ''Longtail'' version of a design that won the Le Mans 24-hour race has been entered by a private collector and estimated at about US$5 million.
Bonhams is also offering a restored 1966 Ford GT40 racer that was formerly owned by the Bolivian tin magnate Jaime Ortiz- Patino and driven by his godson, Dominique Martin, at Monza and Hockenheim races in 1969. Subsequently damaged by fire, it is valued at US$2 million to US$3 million.
A better-preserved Gulf/Mirage team GT40 raced by Jacky Ickx in 1968 and used as the camera car in Steve McQueen's 1971 film ''Le Mans'' may fetch more than US$8m at RM.
None of the three auction houses was prepared to give presale estimates for their sale totals. Last year, the events raised US$166.7 million, up from US$150.2m in 2010.
''I expect prices for the most important cars to keep rising, though the gap could grow between the best and the rest,'' Hartley says.
''We're seeing two types of buyer now. Half of them want to show and race their cars, the other just want to invest. Some clients have recently been telling me to keep the cars for them until they're ready to sell.''