• In the valuation of works of art, the setting of a price is the last step, the result of a discursive attribution of quality; in this regard, aesthetic and commercial evaluations merge. The structure of this mediation is characterised by the concept of the “knowledge market;” knowledge that is ordered and able to spread is essential in order to stabilise the accumulation of value. The boundaries of this circulation of knowledge are fuzzy. It begins in the market and in museums, but also in scholarship. An extended definition of circulation must therefore consider not only objects, actors and money, but also knowledge itself and its media. Such a model of transnational exchange can accommodate both aesthetic and economic aspects. In this way it does not deal with the art market as a clearly separate sphere beyond the art world, but instead relates economic aspects to supposedly purely artistic ones.