Key senators are weighing whether to hold additional hearings on a slew of corporate megamergers under review by the Department of Justice.

A federal judge’s rejection of the department’s challenge to the AT&T-Time Warner merger has fueled speculation that a new wave of acquisitions could join deals already proposed in the healthcare, content and telecommunications industries. How the government responds to the transactions, including the proposed combination of Sprint and T-Mobile, may well define antitrust enforcement under the Trump administration.