[ToddLevin]

You are incorrect - it was not Sotheby's who decided "not to sell", it was the consigner who set their reserve at $70 million, and would not lower it, even though Sothebys actively suggested that they do so a day or two before the sale took place, knowing that they very well might not have somebody who would be willing to bid at the hammer that high. This was entirely the seller's call, and not the auction house's. The seller simply wasn't willing to part with their artwork for less than they felt it was worth, and they were perfectly fine taking it back if it didn't achieve the desired hammer price. It was their artwork, and their decision.