"Auction rooms are democratic", Damien Hirst told The Economist just before the two-day sale of 223 of his new works at Sotheby's London branch last week. "That's what I like about them. Anyone with enough money can buy what they want--immediately. They just have to be prepared to make that final bid."

But democratic is not the same as open.

Sotheby's theory before the auction was simple and compelling: the global contemporary-art market is much bigger than anyone supposes; galleries are exclusive rather than inclusive (meaning they are off-putting to all but the richest buyers); auction houses are friendlier to buyers of every pocket; they are also the most sophisticated global players in the art world and have the best contacts in the realms of new money--Russia, China, India and the Middle East.

If you are rich and impatient, buying through an auction room is the place for you.

The simplest way for Sotheby's to substantiate this theory would have been to publish as much supporting evidence as possible from the Hirst sale. But the furthest Sotheby's went in its after-sale press release was to state that, of the bidders registered for the sale, 16% were new to Sotheby's. A quarter of those, ie just 4%, came from the "new markets", which include Russia, Asia and the Middle East. The press release says nothing about the ratio of bidders to buyers or where they all originated.

Gentle probing produced just one more figure: 24.3% of the buyers in all three sessions of the Hirst sale on September 15th and 16th were new to Sotheby's. In that figure lies the key to the auctioneers' thinking.

Careful notetaking during the sale indicated that the 223 lots were shared out between about 140 different buyers. Some spent more than others. It is believed, for example, that the buyer of the star piece, "The Golden Calf", also purchased two other works. The bullock with gold hooves, horns and halo, all preserved in formaldehyde, set a new world record for the artist at auction, fetching £9.2m ($16.7m), or £10.3m with the auction house's premiums. Another buyer, the by-now famous paddle number L035, bidding on the first evening of the sale through Sotheby's Russian-speaking Alina Davey from the private-client services department, spent £12.9m and bought all nine lots it bid for.

However, by far the biggest group--over 90 buyers--left with just one memento. If 24.3% of the buyers at the auction were new, it means 35 people had never bought from Sotheby's before-35 buyers whose names can be added to Sotheby's contact list, and who may return.

For help in the future is what the auction houses will need. Next month, both Sotheby's and Christie's will face a far tougher test when they hold three days of contemporary-art sales in London. Christie's plans to hold another three similar sales in New York in November. Christie's is offering an important portrait of Francis Bacon by Lucian Freud, which is estimated to sell for £5m-7m, while Sotheby's expects to obtain the same price for a selection of Andy Warhol skulls.

In 2007 Christie's and Sotheby's together sold $2.7 billion worth of post-war and contemporary art. For Christie's alone, that represented a 75% increase in sales on the previous year. By next month, the little oasis represented by the Damien Hirst sale may have been blown completely away by the whirlwind in the financial markets.

The London sales will be the market's first major test. Every buyer, even the person who bid £19,000 for "Beautiful Resolution Spin", the cheapest lot in the Hirst sale, will be crucial. No wonder Sotheby's is keeping its cards close to its chest.

Picture credit: Damien Hirst

(The Art.view column appears every week on Economist.com.)