THE two leading auction houses, Sotheby's and Christie's, have come a long way since the dark days of late 2008, when the sudden collapse of the art market caused their revenues to plummet.

Unlike other models of the market in illicit drugs, it takes into account two factors that are crucial to the way sellers and buyers act that tend not to be present in conventional markets.

According to the will difference of commercial Banks withdrawing from the market, the way of market withdrawal can be divided into two kinds: one is a volunteering type, the other is a forcing type.