THE JOURNAL OF FINANCE • VOL. LXX, NO. 6 • DECEMBER 2015
The People in Your Neighborhood: Social
Interactions and Mutual Fund Portfolios
VERONIKA K. POOL, NOAH STOFFMAN, and SCOTT E. YONKER
∗
ABSTRACT
We find that socially connected fund managers have more similar holdings and trades.
The overlap of funds whose managers reside in the same neighborhood is considerably
higher than that of funds whose managers live in the same city but in different neigh-
borhoods. These effects are larger when managers share a similar ethnic background,
and are not explained by preferences. Valuable information is transmitted through
these peer networks: a long-short strategy composed of stocks purchased minus sold
by neighboring managers delivers positive risk-adjusted returns. Unlike prior em-
pirical work, our tests disentangle the effects of social interactions from community
effects.
DESPITE THE IMPORTANT ROLE professional money managers play in financial
markets, and decades of academic study, relatively little is known about how
they generate investment ideas. Research shows that managers invest in com-
panies headquartered nearby (Coval and Moskowitz (1999, 2001)), and in com-
panies to which they are linked through school networks (Cohen, Frazzini, and
Malloy (2009)). They also choose stocks based on their political ideology (Hong
and Kostovetsky (2012)) and stocks with which they are merely familiar (Pool,
Stoffman, and Yonker (2012)).
But, as Aristotle famously noted, humans are social animals, so perhaps fund
managers also trade stocks that they learn about from other managers. While
numerous papers examine the effects of social interaction on choices in other
domains, 1 there is little empirical evidence on how word-of-mouth communica-
∗
Pool and Stoffman are at the Kelley School of Business, Indiana University. Yonker is at
the charles Ho Dyson School of Applied Economic and Management, Cornell Univesity. We thank
Kenneth Ahern, Matt Billett, Martijn Cremers, Jessie Ellis, Ryan Israelsen, Ken Weakley, Kenneth
Singleton (the Editor), two anonymous referees, and an Associate Editor, as well as seminar
participants at Arizona State University, the College of William and Mary, Federal Reserve Board,
Miami University, University of Alabama, University of Massachusetts–Amherst, University of
Miami, University of Toledo, University of Western Ontario, the Early Career Women in Finance
Conference, the Financial Intermediation Research Society annual meeting, the IU-Notre Dame-
Purdue Summer Symposium, the Second Michigan State Federal Credit Union Conference, and
brown bags at The Ohio State University and Indiana University for helpful comments. Research
support was provided by the Indiana University Kelley School of Business. We have read the
Journal of Finance’s disclosure policy and have no conflicts of interest to disclose.
1
For example, Grinblatt, Keloharju, and Ik¨aheimo (2008) document a substantial influence of
near-neighbors on automobile purchases. Bayer, Ross, and Topa (2008) show the importance of
DOI: 10.1111/jofi.12208
2679
|