An investor-oriented metric for the art market

In the last 30 years the market for paintings has received an increasing amount of attention from economists and financial analysts. They have brought to this field many quantitative techniques already employed in more conventional markets. Most efforts have dealt with returns; specifically, how to compute return indexes for the art market. This is a challenging task not only because this market is fairly illiquid, at least compared with equities and bonds, but also because of its heterogeneity: Every painting is essentially a unique object.