There has been a steady improvement in the demand for top quality impressionist and modern art from investors. The start of the bid summer sales in New York last week saw many high prices achieved which should encourage owners to put their best paintings on the market in the next round of auctions in November.

The new generation of buyers, mainly Americans who have made money from building up technology businesses, is well advised and is concentrating on buying undoubted masterpieces from accepted masters with an excellent provenance.

Sothebys offered 50 works from the collection of the late Jock and Betsey Whitney for auction, selling them all for $128.3 million (€120 million). A Cezanne still-life sold for $60.5 million, the fourth highest price paid for a work of art at auction. Commenting on the auction results, Mr Charles Moffett, co-chairman of Impressionist and Modern Art said he believes the momentum will be maintained.

"People who hesitate now will be left behind. It's a very savvy market. Anything of quality and anything fresh will do very well but vendors with excessive expectations will get a predictable response."

Over the week Christies brought in $163 million, a substantial improvement over the $132 million achieved last year.