David Hockney, 1972. Sold for $90M in 2018 — record for a living artist. Private collection.
From Wikipedia
Portrait of an Artist (Pool with Two Figures) is a large acrylic-on-canvas pop art painting by British artist David Hockney, completed in May 1972. It measures 7 ft × 10 ft (2.1 m × 3.0 m), and depicts two figures: one swimming underwater and one clothed male figure looking down at the swimmer. In November 2018, it sold for $90.3 million, at that time the highest price ever paid at auction for a painting by a living artist.