International collective action: concentration indices in selected areas

Source: Bruegel. Note: the figure indicates in which areas of international cooperation collective action might be more effective, on the basis that collective action tends to be easier when significant players are only a few. The figure adapts the Herfindahl index of market concentration, which varies between zero (perfect atomisation) and one (complete concentration). The concentration scores are much higher for competition policy and banking regulation than for trade and internet regulation. The index is also influenced by whether EU countries act individually or jointly. See https://bruegel.org/2019/08/how-long-is-the-head-table/.