The Justice Department and a group of states plan to sue Live Nation Entertainment, the concert giant that owns Ticketmaster, as soon as Thursday, accusing it of illegally maintaining a monopoly in the live entertainment industry, said three people familiar with the matter.

The government plans to argue in a lawsuit that Live Nation shored up its power through Ticketmaster’s exclusive ticketing contracts with concert venues, as well as the company’s dominance over concert tours and other businesses like venue management, said two of the people, who declined to be named because the lawsuit was still private. That helped the company maintain a monopoly, raising prices and fees for consumers and limiting innovation in the ticket industry, the people said.

The government will argue that tours promoted by the company were more likely to play venues where Ticketmaster was the exclusive ticket service, one of the people said, and that Live Nation’s artists played venues that it owns.

Live Nation is a colossus of the concert world and a force in the lives of musicians and fans alike. Its scale and reach far exceed those of any competitor, encompassing concert promotion, ticketing, artist management and the operation of hundreds of venues and festivals around the world.

The Ticketmaster division alone sells 600 million tickets a year to events around the world. According to some estimates, it handles ticketing for 70 percent to 80 percent of major concert venues in the United States.

Lawmakers, fans and competitors have accused the company of engaging in practices that harm rivals and drive up ticket prices and fees. At a congressional hearing early last year, prompted by a Taylor Swift tour presale on Ticketmaster that left millions of people unable to purchase tickets, senators from both parties called Live Nation a monopoly.

The company has denied that it sets high prices and fees, saying that artists and other parties like major venues are responsible.

A spokeswoman for the Justice Department declined to comment. A spokeswoman for Live Nation declined to comment. Bloomberg News earlier reported the lawsuit was imminent.

In recent years, American regulators have sued other major companies, testing century-old antitrust laws against new power wielded by major companies over consumers. The Justice Department sued Apple in March, arguing the company has made it difficult for customers to ditch its devices, and has already brought two cases arguing Google violated antitrust laws. The Federal Trade Commission last year filed an antitrust lawsuit against Amazon for harming sellers on its platform and is pursuing another against Meta, in part for its acquisitions of Instagram, Facebook and WhatsApp.

The Justice Department allowed Live Nation, the world’s largest concert promoter, to buy Ticketmaster in 2010 under certain conditions laid out in a legal agreement. If venues did not use Ticketmaster, for example, Live Nation could not threaten to pull concert tours.

In 2019, however, the Justice Department found that Live Nation had violated those terms and modified and extended the agreement.

The Justice Department’s latest investigation of Live Nation began in 2022. Live Nation simultaneously ramped up its lobbying efforts, spending $2.4 million on federal lobbying in 2023, up from $1.1 million in 2022, according to filings available through the nonpartisan website OpenSecrets.

In April, the company co-hosted a lavish party in Washington ahead of the annual White House Correspondents’ Association dinner that featured a performance by the country singer Jelly Roll and cocktail napkins that displayed positive facts about Live Nation’s impact on the economy, like the billions it says it pays to artists.

Under pressure from the White House, Live Nation said in June that it would begin to show prices for shows at venues it owns that included all charges, including extra fees. The Federal Trade Commission has proposed a rule that would ban hidden fees.

A former chairman of the Federal Trade Commission, Bill Kovacic, said Wednesday that a lawsuit against the company would be a rebuke of earlier antitrust officials who had allowed the company to grow to its current size.

“It’s another way of saying earlier policy failed and failed badly,” he said.