The return of Donald Trump to the U.S. presidency raises important questions about what to expect from antitrust agencies over the next four years and what a Republican FTC and DOJ will prioritize in Trump’s second term. During the Biden Administration, FTC Chair Lina Khan expanded enforcement, applying creative theories of harm, bringing hard-to-win cases, and attempting to make more lasting changes via new guidelines, rules and policy statements. Chair Khan’s FTC and Jonathan Kanter’s DOJ took aggressive stances across sectors, particularly technology and healthcare, and against private equity. Trump’s first term, too, departed from conservative norms in its tech challenges. However, a Republican-led FTC will likely roll back many of Chair Khan’s initiatives, such as the FTC’s Section 5 statement on unfair competition and the non-compete rulemaking. It is also likely that the 2023 DOJ and FTC merger guidelines could be abandoned or altered. Yet, ambiguities exist regarding the role of J.D. Vance in antitrust enforcement, as he has signaled support for some of Chair Khan’s policies and actions, and the uncertain influence of Elon Musk in Trump’s inner circle. Regardless, change should be expected and businesses can likely expect a more merger-friendly regime to assume power in January, and a return to traditional theories of harm focused less on market structure and more on consumer impact and prices, an issue close to public concern.