Charlotte Higgins replies:
What is a painting worth? Who can say: in practical terms, the value of a work of art is simply what two people, a vendor and a buyer, agree it to be.
In the case of Jackson Pollock's Number 5, 1948, which was reported by the New York Times on Thursday to have been sold by David Geffen to the Mexican financier David Martinez for "about" $140m (£74m), a note of caution is required. Though Sotheby's brokered the deal, the sale was not made through auction (where prices paid are public knowledge), and the rumoured amount may never be properly confirmed.
Prices in the art market, like any other, are partly determined by supply and demand. Pollock was not a prolific artist - he died at 44 - and his works rarely come up for sale. As an indication of his desirability, Gagosian Gallery paid $20m for a mere work on paper two and a half years ago, according to Georgina Adam, art market editor of the Art Newspaper.
The artists who have recently held the record for most expensive artwork have been Klimt (whose Adele Bloch-Bauer I was sold to Ronald Lauder in June for a rumoured $135m) and Picasso. That the new record-holder is Pollock may mark a taste-change. According to the art sociologist Sarah Thornton, "There is a general shift in taste towards post-war painting, and particularly to the post rock'n'roll period.Who wants a home that looks like their grandparents'? They want status symbols, and those status symbols are getting closer and closer to our time." The particular price of the Pollock also reflects a general exuberance in the postwar and contemporary art markets. "To call the market lively is an understatement. High as a kite is more accurate," said Dr Thornton.
According to Ms Adam, the price for the Pollock is also in line with the current desirability of American art - among, of course, fabulously wealthy US collectors. "There's a colossal market for American art. A weathervane sold for $5.8m at Sotheby's last month. The estimate was $100,000-$150,000." Next question: why is a weathervane worth $5.8m?
