We explore the efforts and performance of different complementors following intensified platform competition. We argue that multihoming complementors exert more effort than their single-homing counterparts only when platforms target heterogeneous market segments and between-platform competition for users is relatively low. When platforms compete for the same user base, however, multihoming complementors exert less effort and thus underperform relative to single-homing complementors due to their different incentives: For multihoming complementors an increase in the attractiveness of one platform comes at the expense of a reduced attractiveness of the other. We find empirical support for our theory using a unique, hand-collected dataset of YouTube gaming channels faced with an external shock that increased content overlap and thus competition with the rival gaming platform Twitch.
