We document a sizable increase in the concentration of active users toward the top mobile apps. In narrowly defined categories, the share of active users for the top app increases from 38% in fall 2015 to 47% in spring 2022. This sharp rise in user concentration can be primarily attributed to...

Despite the importance of intra-firm trades in theories of the firm, an empirical literature using proxy measures has documented surprisingly little such trade. I revisit this conclusion using economy-wide firm-level data from Korea, where related-party trades are directly observable. I show...

This paper analyzes the implications of the gradual rise in bank concentration since the 1990s for the transmission of monetary policy. I use branch-level data on deposit and loan rates to evaluate the monetary policy pass-through conditional on the level of local bank concentration and bank...

The Herfindahl-Hirschman index (HHI) appears to be the most widely used index of market or industrial concentration. It is a summary measure that indicates the degree of competition, market power, and efficiency within a market or an industry. The HHI is also used by government agencies when...

In this paper, we provide a new set of stylised facts on firm provision of on-the-job training and labor market competition. We exploit job ad texts taking a supervised machine learning approach to identify training offers. We find that around 20% of US job posts offer on-the-job training, with...

“Self-preferencing” refers to situations in which a firm favors, or “preferences” its own products over those of rivals. Of course, it would literally be “self preferencing” for a producer to sell nothing but its own products. That type of self-preferencing has not provoked much...