The Independent points to the Amadeo Modigliani’s dissolute life as the source of his art’s value. In the process they give us this brief overview of Modigliani’s auction history, especially the sculptures:

Several Modigliani portraits have recently hit the auction rooms, generating excitement. The earliest recorded auction-sale price for one of his paintings is 1986, when Jeanne Hébuterne (au Foulard) was sold at Christie’s for $2.9m (£1.95m). When last offered for auction, in 2004, its estimate was between $8m and $10m. In May 1997, The Son of the Concierge was sold, again at Christie’s New York, for $5.8m. In Sotheby’s in 2006, it went under the hammer for $31m. According to Artprice, which assesses the fluctuations of investment values in art, between 2004 and 2005 alone, Modigliani’s value increased by between 45 and 64 per cent. And his sculptures, a small corner of his output, have become a goldmine. Tête de Femme, carved in 1911-12, was sold in 1995 for $1,047,500. Six years later, in 2001, it went for $3.8m at the Phillips auction house. That was then the highest price paid for a Modigliani carving. Nine years later, the value of his stone heads has increased by a factor of 10.

Sex and Drugs and Priceless Art (The Independent)