Does the internet increase competition? To address this question, I exploit two institutional details unique to Germany: (1) Some municipalities received glass fibre cables that cannot be upgraded to DSL; I use these municipalities as a treatment group with reduced online competition. (2) German law mandates resale price maintenance for books; I compare three retailing sectors, electronics (price competition), books (no price competition), and food (no online sales), to identify the effect of price competition: The effect of price competition is highly significant. Full broadband access reduces offline electronics retailers' producer rents by 1.5 percent per year from 1999 to 2007.
Internet Market Structure Retail Competition Differences in Differences