Skate’s Art Investment Review had some strong words for both online auction price databases earlier this month:

Following the release of very encouraging 2010 financial results and contrary to the firm’s guidance and to Skate’s expectations, Artnet’s disappointing 1Q 2011 financials show losses with online auctions and a failure to grow the business as quickly as the firm had anticipated. This is a very real concern given that Artnet no longer has the pioneer advantage in the field of online art dealing. […]

In all fairness, while we are disappointed with Artnet this year so far, we are truly bedeviled by Artprice. The Lyon-based art market data provider’s shares are up 245% (sic!) on a year-to-date basis. We see no rational reason behind this increase, especially since Artprice itself has not shared any news to warrant it. This marginally profitable company makes less than $10 million in annual sales, but today its valuation is virtually on par with Switzerland’s MCH Group, the Art Basel and Hong Kong International Art Fair owner that made a CHF 37 million (approximately $40 million) net profit in 2010. Our word of wisdom to all art stocks investors is to take current Artprice’s valuation with a massive grain of salt and prepare for a likely crashing nosedive of Artprice shares that would be triggered should anyone attempt to sell the stock in this illiquid and clearly inflated market environment.

Skate’s Semi-Annual Industry Forecast (Skate’s Art Investment Review)