Abstract Why do so few mutual fund families launch so many funds and styles around the world? We argue that launching numerous funds on an increasingly granular style grid allows incumbent families to congest the product space and deter market entry. Key to this argument is the persistently low dimensionality of the mutual fund product space, a fact we establish by analyzing the names of over 40,000 equity funds sold in 91 countries between 1931 and 2015. Over time, the strategy of filling up the style grid has led to the dominance of few families offering large, granular, and similar fund menus. Authors have furnished an Internet Appendix, which is available on the Oxford University Press Web site next to the link to the final published paper online.

ABSTRACT This paper develops an empirical methodology for extracting pricing factors from investor portfolio data. We apply this approach to the stockholdings of Norwegian individual investors from 1997 to 2017. A two‐factor model, featuring the market portfolio and a long‐short portfolio constructed from the holdings of investors sorted by age or wealth, explains both the common variation in portfolio holdings and the cross section of stock returns. Portfolio tilts toward the long‐short investor factor correlate with indebtedness, macroeconomic exposure, gender, and investment experience. Our paper illustrates the benefits of using holdings data for explaining the risk premia of financial assets.