In many competitive settings consumers buy multiple product categories, and some prefer to use a single firm, generating complementary cross-category price effects. To study pricing in supermarkets, an organizational form where these effects are internalized, we develop a multi-category...

The UK supermarket industry has a high profile because of its large share of household budgets. In 2003 the UK competition authorities blocked all potential mergers between the top-three firms and the fourth. After this, there was an apparent consensus that mergers between the largest four...