Who Cares?
It's been a long long time since the banking system failed. Investment choices of old money controls the willingness to piss away $40,000,000.00 on a painting. In order for Sotheby to maintain it's image as a the great pompus ass of art dealers it places minumim guarentees on the auctions. A possible example would be when the market says a $40,000,000.00 painting is only worth $10,000,000.00 Sotheby is stuck buying the painting for $20,000,000.00 and then having to dump it descretly for $10,000,000.00
Last October's auction that cost Sotheby so much money won't be the last money pit they fell in to.