This paper investigates the factors that influence hammer price in fine art auctions. Unlike previous studies, this thesis focuses solely on Mark Rothko’s abstract painting auction results, which eliminates pricing variation from multiple artists or painting genres. Using a freshly constructed database that covers all Rothko auction records from 1985 to 2017, this thesis affirms the presence of declining price anomaly. Auction house experts’ pre-sale estimates are shown to be largely unbiased with a marginal downward pricing tendency. Furthermore, size is a statistically significant variable that affects hammer price and Rothko’s vertical compositions are favored in the auction market.