Mergers of Complements: Are Consumer Welfare, Economic Growth, and Market Concentration Compatible?

Mergers of complements are gaining prominence in today’s interconnected and digital economies, drawing increased attention from competition authorities, practitioners, and academics. In various jurisdictions, competition authorities are mandated to promote consumer welfare. However, amid fiscal pressures, high living costs, and geopolitical uncertainty, promoting economic growth has become more critical than ever. At the same time, empirical evidence points to a broad rise in market concentration across both the US and EU over recent decades.

In a recent Concurrences article, RBB’s David HenriquesDavid HenriquesSenior Associate, together with Bruno Carballa Smichowski (European Commission, UCL), examine two main questions that are particularly relevant for merger control.

1) To what extent is the consumer welfare standard compatible with economic growth?
2) To what extent is it compatible with rising market concentration?

Using standard models of imperfect price competition, two main conclusions emerge.

First, under the models considered, they do not identify any configuration in which a merger of complements increases GDP while harming consumers. However, a tension may arise in the opposite direction, as there are settings in which consumer welfare increases while GDP declines.

Second, higher market concentration following a merger of complements does not indicate consumer harm. In fact, across all models tested, they found no case where a merger increased concentration while reducing consumer welfare. Consumer welfare may also increase when concentration falls. Market concentration is therefore not a reliable proxy for welfare effects in the context of mergers of complements.

From a policy perspective, promoting economic growth does not necessarily call for more permissive enforcement. Their findings also support a greater role for effects-based analysis and caution against relying on structural presumptions based solely on concentration thresholds.

Article published in Concurrences Review, N° 9-2026.

Read the full article here.