Speaking at the Wall Street Journal's CEO Council Summit, Khan said that it was the Justice Department that approved the merger of Ticketmaster and Live Nation in 2010 and referenced a report that the department had a probe under way.

"There can be concerns that when firms become (large) they can become too big to care," she added, saying that giant firms may feel like they don't need to invest in innovation because they're not facing tough competition.

"There's been public reporting that the Justice Department continues to look at this and I'm sure it's top of mind for them, given all the incoming that they're getting," she added.

There will also be a congressional hearing, likely this month, on the debacle in November when Ticketmaster put tickets on sale for Taylor Swift's Eras tour, and some fans struggled for hours with the ticket sale website.

Ticketmaster has blamed problems with presale ticketing for the tour, the pop superstar's first in five years, on unprecedented demand and an effort to keep out bots run by ticket scalpers.

For her part, Swift has said it was "excruciating" for her to watch fans struggle to secure tickets and that she had been assured that Ticketmaster could handle large demand.

Neither Ticketmaster nor the Justice Department immediately responded to requests for comment.

Khan also said that the FTC was not investigating cryptocurrency firm FTX, whose dramatic collapse sparked fears of contagion and prompted calls for more crypto regulation.

(Reporting by Diane Bartz; Editing by Cynthia Osterman)