Prices

Artprice, an auction database, says unsold works at auctions held since September 1 this year rose to 39.2 percent against 36.8 percent last year in the same period. On October 1, prices had slipped 4.45 percent in a year and there were 20.5 percent less auctions in the last six weeks.

And auctions early this month in Asia and London were "disappointing", with more than half of works up for sale left unsold at times, according to specialist insider newsletter The Baer Faxt.

"Masterpieces," said Curiel of Christie's, "are seeing excellent prices, but sales will be more difficult for less exceptional works or those believed to be over-rated. Before this summer, it was never a problem to issue a high or very high estimate. But now it is."

Read all about it here.