Sex sells: why Modigliani’s 98-year-old hymn to lust is worth $170m

Painted through an absinthe haze as the first world war raged, Amedeo Modigliani’s Nu couché mixes modernist thrills with age-old hedonism. No wonder it still seduces

Swiss couple Iwan and Manuela Wirth top art power list

Wirths praised for changing model of how art is bought and sold, while Ai Weiwei ranks second and Nicholas Serota falls to fifth

Going, going, gone: how Sotheby’s and Christie’s still lose out on big sales

Despite increasing prices of art, big profits do not always trickle down to auction houses – thanks to generous guarantees to ultra-rich sellers

Super rich shift their thrills from luxury goods to costly experiences

Gourmet dining, private flights, bespoke safaris, slimming clinics and art auctions emerging as top status symbols