Siggelkow, Nicolaj2023-05-222023-05-222003-06-012016-06-23https://repository.upenn.edu/handle/20.500.14332/40519In an intra-industry setting, firm-focus is found to be positively correlated with the ability of firms to produce high-value products, while the overall effect of focus on firm performance is negative due to missed demand externalities generated by a broad product offering. In particular, it is shown that U.S. mutual funds that belong to more focused fund providers outperform similar funds offered by more diversified providers. An explanation based on alignment among a provider's activities is consistent with this result. Cash inflows into fund providers—a measure related to fund provider profitability—is, however, negatively correlated with focus in fund offerings.This is the peer reviewed version of the following article: Siggelkow, N. (2003), Why Focus? A Study Of Intra-Industry Focus Effects. The Journal of Industrial Economics, 51: 121–150., which has been published in final form at doi: 10.1111/1467-6451.00195. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving: http://olabout.wiley.com/WileyCDA/Section/id-820227.html#terms.Business Administration, Management, and OperationsArticle