We provide a general characterization of which firms will select alternative ways of serving a market. If and only if firms' maximum profits are supermodular in production and marketaccess costs, more efficient firms will select into the activity with lower market-access costs. Our result...

We provide a general characterization of which firms will select alternative ways of serving a market. If and only if firms' maximum profits are supermodular in production and marketaccess costs, more efficient firms will select into the activity with lower market-access costs. Our result...