The paper firstly deals with the main theories of prices of visual art goods considering, in particular, the “stars”. whose high value reflects the rarity and the convexity of the demand by the main purchasers, interested in “famous” goods. The contingent valuation methodology is also discussed. The second section presents an art market matrix focusing on the assets’ value. The role of information, regulations and purchasing power for the art market values is discussed, on the basis of statistical analysis of the auction prices of the “informal art” and of the “pop art” of US authors compared with Europeans and Italians. In the third section a diffusion index is presented and used to test the influence of “information” on the art market value. It is argued that certification may improve both the information and economic appreciation of the works of the great Italian masters.