Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
Art is often used as an investment vehicle. Given the importance of market efficiency in finance, we use a large auction-based index to test whether the art market is weakly efficient. Evidence reveals that returns on artworks exhibit high positive auto-correlation. We attribute this result to price truncation resulting from unobservable reserve prices in auctions. We conclude that the art market is not efficient, mainly because price formation is opaque to outsiders who lack information on unsold artworks.