  I examine the implications of cross-market mergers of suppliers to
intermediaries that bundle products for consumers. These mergers are
controversial. Some argue that suppliers' products will be substitutes for
intermediaries, despite not being substitutes for consumers. Others contend
that because bundling makes products complements for consumers, products must
be complements for intermediaries. I contribute to this debate by showing that
two products can be complements for consumers but substitutes for
intermediaries when the products serve a similar role in attracting consumers
to purchase the bundle. This result leads to new recommendations and helps
explain why cross-market hospital mergers raise prices.
