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Momentum and Autocorrelation in Stock Returns

Jonathan Lewellen

MIT Sloan School of Management

Review of Financial Studies 2002

This article studies momentum in stock returns, focusing on the role of industry, size, and book-to-market (B/M) factors. Size and B/M portfolios exhibit momentum as strong as that in individual stocks and industries. The size and B/M portfolios are well diversified, so momentum cannot be attributed to firm- or industry-specific returns. Further, industry, size, and B/M portfolios are negatively autocorrelated and cross-serially correlated over intermediate horizons. The evidence suggests that stocks covary “too strongly” with each other. I argue that excess covariance, not underreaction, explains momentum in the portfolios.

DOI
10.1093/rfs/15.2.533
Volume
15 (2)
Pages
533-564
Language
en
Export
BibTeX
Sources
crossref openalex