Over the last years, several reports highlighted the market power of very large online platforms that are gatekeeping intermediaries between businesses and consumers, and the difficulty for classic competition policy tools to deal effectively with anti-competitive practices in these platforms....

We analyze the impact of a merger on firms' incentives to innovate. We show that the merging parties always decrease their innovation efforts post-merger while the outsiders to the merger respond by increasing their effort. A merger tends to reduce overall innovation. Consumers are always worse...