Now that auction houses are no longer offering guarantees, an increasing number of purchases are likely to take placeas discreet transactions brokered by art dealers

The large-scale “disaster painting” is the most expensive Andy Warhol ever to sell at auction

Having set a record for the artist at auction, the collectors put the art to work

As Tate Britain opens a major travelling retrospective, we examine the factors underpinning the meteoric rise in prices for the artist’s work and reveal the identity of his biggest collectors

The London-based Russian billionaire has bought the record-breaking works; he has not previously been known to collect art

The ruling Al-Thanis bought the artist’s Lullaby Spring at Sotheby’s last year for £9.7m and are also believed to have purchased the Rockefeller Rothko for $72.8m