The Social Welfare of Stock Market Mispricing

61 Pages Posted: 1 Dec 2023 Last revised: 24 Apr 2024

See all articles by Shikun Ke

Shikun Ke

Yale School of Management

Date Written: December 19, 2022


This paper studies the social value of eliminating mispricing in the US stock markets. By characterizing a model in which active managers extract abnormal value from trading against mispricing, I show that the mispricing of a stock relative to a benchmark asset pricing model exactly equals to the marginal social value of mispricing trading. Combining conditional mispricing estimates and a calibrated price impact function, I find that the mispricing relative to CAPM translates into a welfare cost of about 3.1% of annual nominal GDP in the US, suggesting a large potential welfare gain from active management that eliminates stock mispricing.

Keywords: Mispricing, Welfare, Price Impact, CAPM, Instrumented Factor Model

JEL Classification: G10, G12, G14, G17

Suggested Citation

Ke, Shikun, The Social Welfare of Stock Market Mispricing (December 19, 2022). Available at SSRN: or

Shikun Ke (Contact Author)

Yale School of Management ( email )

165 Whitney Ave
New Haven, CT 06511

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