Biased Auctioneers

37 Pages Posted: 20 Mar 2019 Last revised: 17 Jul 2020

See all articles by Mathieu Aubry

Mathieu Aubry

Ecole Nationale des Ponts et Chaussées (ENPC)

Roman Kräussl

Luxembourg School of Finance; Hoover Institution, Stanford University

Gustavo Manso

University of California, Berkeley - Haas School of Business

Christophe Spaenjers

HEC Paris - Finance Department

Date Written: July 17, 2020


We study biases in art auction house estimates by generating our own counterfactual pre-sale valuations through a purpose-built machine-learning algorithm that considers both visual and non-visual artwork characteristics. We find that auction house estimates are not informationally efficient, as they can be improved upon as predictors of transaction prices. Moreover, estimates show systematic over- and undervaluation patterns that are predictable ex ante. Finally, we find that biases in pre-sale estimates drive market participants’ investment outcomes: higher relative estimates are associated with both lower sale rates and lower future capital gains.

Keywords: art, auctions, experts, asset valuation, biases, machine learning, computer vision

JEL Classification: C50, D44, G12, Z11

Suggested Citation

Aubry, Mathieu and Kraeussl, Roman and Manso, Gustavo and Spaenjers, Christophe, Biased Auctioneers (July 17, 2020). HEC Paris Research Paper No. FIN-2019-1332, 10th Miami Behavioral Finance Conference, Available at SSRN: or

Mathieu Aubry

Ecole Nationale des Ponts et Chaussées (ENPC) ( email )

28, rue des Saints-Peres
75343 Paris Cedex 07


Roman Kraeussl

Luxembourg School of Finance ( email )

4, rue Albert Borschette
Luxembourg, 1246
+3524666445442 (Phone)


Hoover Institution, Stanford University ( email )

Stanford, CA 94305
United States

Gustavo Manso

University of California, Berkeley - Haas School of Business ( email )

545 Student Services Building, #1900
2220 Piedmont Avenue
Berkeley, CA 94720
United States

Christophe Spaenjers (Contact Author)

HEC Paris - Finance Department ( email )

1 rue de la Liberation
Jouy-en-Josas Cedex, 78351

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