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Style Concentration in Ownership and Expected Stock Returns

75 Pages Posted: 7 Nov 2017  

Gikas A. Hardouvelis

University of Piraeus; Centre for Economic Policy Research (CEPR)

Georgios I. Karalas

LSE - Department of Finance; University of Piraeus

Date Written: October 2017


We examine the relation of expected stock returns with fund style concentration in stock ownership over the period 1997-2015. Concentration is measured by the Herfindahl index H of the shares of different investment styles in the ownership of stocks and represents a measure of investor inattention in stocks. Decile portfolios on H reveal a strong positive association of H with future returns, with the long-short portfolio on H having significant alphas after passing through the five-factor Fama-French (2015) model.

The econometric results confirm the positive association and are robust to the inclusion of known risk-factors as determinants of expected stock returns, the returns of the investment styles themselves, plus a set of style-related control variables and other liquidity, size, or volatility characteristics of stocks. The relation coexists with short-run price and style momentum and long-run style and price reversals of Barberis and Shleifer (2003) and remains present over multi-year horizons of stock returns, being both economically and statistically significant.

The results are consistent with the model of Merton (1987), which claims a stock’s excess risk premium over the CAPM premium, is the product of investor participation (which is proxied by H in our framework), idiosyncratic volatility and size. These results also shed light on the small firm effect.

Keywords: Asset pricing, Style Investing, Stock Ownership Concentration, Institutional Investors, Multi-period Expected Stock Returns, Size Effect

JEL Classification: G12, G23, G4

Suggested Citation

Hardouvelis, Gikas A. and Karalas, Georgios I., Style Concentration in Ownership and Expected Stock Returns (October 2017). Available at SSRN:

Gikas Hardouvelis (Contact Author)

University of Piraeus ( email )

80 Karaoli & Dimitriou Str.
18534 Piraeus, 185 34 -GR
+32010 4142323 (Phone)
+3210 6724848 (Fax)


Centre for Economic Policy Research (CEPR) ( email )

77 Bastwick Street
London, EC1V 3PZ
United Kingdom

Georgios Karalas

LSE - Department of Finance ( email )

United Kingdom

University of Piraeus ( email )

80 Karaoli & Dimitriou Str.
18534 Piraeus, 185 34 -GR

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