In a letter to the U.S. Attorney General Merrick Garland, senators Richard Blumenthal of Connecticut, Amy Klobuchar of Minnesota and Edward J. Markey of Massachusetts said that "an investigation alone does nothing for the stakeholders already harmed by Live Nation's market dominance and seemingly ongoing anticompetitive behavior."

If the company, which controls an estimated 60% of the market for promotion of major concerts and events "has continued to abuse its dominant market position" despite two previous DOJ actions, "we urge the Department to consider unwinding the Ticketmaster-Live Nation merger and breaking up the company," they wrote.

"This may be the only way to truly protect consumers, artists, and venue operators and to restore competition in the ticketing market."

Live Nation and Ticketmaster merged in 2010 after a DOJ-brokered settlement that officials said would encourage competition and send ticket prices down. Instead, "across all genres and venues, Ticketmaster prices have more than tripled in the past 20 years," the senators wrote.

Tickets for Swift's U.S. 'Eras' concert tour, which went on sale last week, were hard to get amid website outages, poor customer service and long wait times, and are selling for thousands of dollars on resale sites.

The DOJ has proven in recent years much more willing to file antitrust lawsuits against giant companies - including the ongoing December 2020 lawsuit against Google - and fight mergers.

(Reporting by Heather Timmons; Editing by Stephen Coates)