Contractual theories of vertical integration derive firm boundaries as an efficient response to market transaction costs. These theories predict a relationship between underlying features of transactions and observed integration decisions. There has been some progress in testing these...

We estimate the sensitivity of Internet retail purchasing to sales taxes using data from the eBay marketplace. Our Örst approach exploits the fact that seller locations are revealed only after buyers have expressed interest in an item by clicking on its listing. We use millions of location...