In the study, we took a broad look across Morningstar Categories to understand similarities and differences between their levels of active share. This allowed us to show just how different categories are in terms of their active-share profiles, confirming the intuition that top-heavy indexes represent a more difficult investment universe from which to build high-active-share portfolios, at least without taking meaningful off-benchmark positions. The number of securities in a benchmark also plays a role, but to a lesser extent than concentration.