We study competitive interactions between Intel and Microsoft, two producers of complementary products. In a system of complements, like the PC, the value of the final product depends on how well the different components work together. This, in turn, depends on the firms' investment in...

We analyze the optimal strategy of a high-quality incumbent that faces a low-quality ad-sponsored competitor. In addition to competing through adjustments of tactical variables such as price or the number of ads a product carries, we allow the incumbent to consider changes in its business model....