An art collection is tipped to break the $1 billion barrier at auction for the first time when Christie's sells works belonging to the late Microsoft co-founder Paul Allen.
The two-day sale, taking place in New York this week, comes as experts say the super-wealthy are viewing art as a safe investment this year amid a tumultuous global economy and Russia's war in Ukraine.
Allen made his fortune with the establishment of the PC operating system with his better-known Microsoft co-founder Bill Gates in 1975.
He amassed a huge art collection, which he would lend to museums before his death in 2018 at the age of 65.
The 150 works, to be sold on Wednesday and Thursday at the Christie's headquarters in Manhattan, trace more than 500 years of art history, from Botticelli and Canaletto to Georgia O'Keeffe and Louise Bourgeois, via Claude Monet, Francis Bacon and Edward Hopper.
The collection is also unique for its value: several masterpieces are estimated to fetch more than $100 million.
They include French painter Paul Cezanne's Montagne Sainte-Victoire (1888-1890), which heralded cubism, and Georges Seurat's 1888 work Les Poseuses, Ensemble (small version), a renowned work of pointillism.
Also going under the gavel is Vincent Van Gogh's Orchard with Cypresses and a painting from Paul Gauguin's Tahitian period, Maternity II (1899).
Allen left Microsoft in 1983, due to health problems and a deteriorating relationship with Gates, who remained in charge of the company until 2000.
Despite their strained friendship, Allen signed Gates's Giving Pledge campaign and all proceeds from the auction will be donated to charity.
Christie's hopes the total sales will become part of art market history and top $1 billion.
The current auction record for a private collection was set this spring by the US couple Harry and Linda Macklowe, with $922 million fetched in auctions conducted by Sotheby's.
This year is shaping up as one of the biggest ever in the art market.
Besides the Macklowe auction, an Andy Warhol portrait of Marilyn Monroe sold in May for $195 million, a record for a piece of 20th-century art.
Another famous Warhol, White Disaster (White Car Crash 19 Times) from 1963, depicting a series of images of a brutal car crash, is due to be sold on November 16 by Sotheby's, with a pre-sale estimate of more than $80 million.
"Clients want to diversify their assets, because they can enjoy it, and they know that most pieces continue increasing in value over time," Adrien Meyer, says co-chairman of Impressionist & Modern Art at Christie's.
"There are more billionaires than they are masterpieces, in essence. The demand is very diversified."
Jeremiah Evarts, vice president at rival auction house Phillips, agreed that the art market is showing "no signs" of slowing down amid several world crises.
"A lot of collectors are looking at the 20th century and perhaps feel more secure buying a Picasso, a Chagall or a Magritte," he says.