(the United States Federal Trade Commission was founded in 1914; the first European Commissioner for Competition was designated in 1958) and their history in middle-income economies is more recent. Mexico established the Federal Competition Commission in 1993 as part of a broad reform agenda focused on economic modernization led by President Carlos Salinas de Gortari. The Commission today is regarded by peers as a member of the antitrust vanguard (OECD, 2020). Narrowly, the Mexican experience is informative for other middleincome countries about what an antitrust authority can achieve in a relatively short period when starting from scratch and following international good practices. Broadly, the Mexican experience highlights the potential contribution of antitrust to aggregate outcomes, especially in an economy characterized by higher inequality, slower productivity growth, and greater misallocation compared to other OECD countries (Levy Algazi and Walton, 2009; Hsieh and Klenow, 2014; Levy Algazi et al., 2018).<sup>8</sup> Our effort to quantify the aggregate effects of antitrust enforcement stands on the shoulders of a large literature that has studied the effects of antitrust sanctions in individual cases. One strand of this literature uses event studies to estimate changes in the equity prices of publicly traded firms subject to investigation immediately after news of an indictment is released (Bittlingmayer, 1993; Duso, Neven and R ̈oller, 2007; Aguzzoni, Langus and Motta, 2013). In contrast, we look at effects on entire industries over horizons of about 10 years, more similarly to Sproul (1993), which studies the effects of US Department of Justice indictments on prices over 10 years but not other outcomes and does not use closed cases as a counterfactual as we do. While equity prices are expected to respond immediately to news about enforcement, effects on industry-wide productivity and concentration could take longer to emerge and so it is advantageous to evaluate them over a longer time horizon.

Another strand of literature combines reduced form and structural analysis to estimate the effects of antitrust sanctions on welfare in a single industry (Porter and Zona, 1993; Asker, 2010; Igami and Sugaya, 2021; Starc and Wollmann, 2022; Barkley, 2023). This literature has focused primarily on cartels engaging in bid rigging and price fixing, practices which ex-ante are expected to be harmful and so are per se illegal in most jurisdictions. Like this literature, we evaluate the effects of sanctioning these so-called absolute monopolistic practices, but in contrast to this literature, we are also able to compare these effects to sanctions of relative monopolistic practices like price discrimination, and vertical control, which theoretically could have beneficial effects, and so are subject to different legal standards. We find that sanctions of such practices do create benefits for consumers and workers, but that these benefits are smaller than sanctions of absolute monopolistic practices. This result validates

> 8See Iacovone, Munoz Moreno, Olaberria and Pereira Lopez (2022) for a recent analysis of Mexico’s productivity trends and dynamics.

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