A new paper from Goetzmann, Renneboog & Spaenjers. From the abstract:
"This paper investigates the impact of equity markets and top incomes on art prices. ... [W]e demonstrate that ... equity market returns have a significant impact on the price level in the art market. Over a shorter time frame, we also find empirical evidence that an increase in income inequality may lead to higher prices for art .... Finally, the results of Johansen cointegration tests strongly suggest the existence of a long-term relation between top incomes and art prices."