I guess it pays to have a retrospective art exhibitions at two major US museums in one year. The German artist Martin Kippenberger is included in Sotheby's May catalogue; in fact, his painting is featured on the cover (it's also featured in Sotheby's Private View: Contemporary Art, which is distributed to private collectors). Sotheby's Director of Contemporary Art Tobias Meyer pitches the Kippenberger painting, a large-scale self portrait, with a very high estimate: $3.5 to $4.0 million. Kippenberger's auction prices in the past have been around $300k to $600k for large paintings.
The painting on sale at Sotheby's is part of a series based on a photography of Picasso in his underwear, standing on the steps of his mansion, posing as a regal king-artist. All the paintings in this series are good, although I would consider them some of Kippenberger's more conservative work. People can read and understand them easily, compared to some of his other works, which may account for Meyer's substantial estimate.