SAN FRANCISCO, May 31 (Reuters) - Live Nation

Entertainment ( LYV ) said on Friday it was investigating a data

breach at its Ticketmaster unit that it discovered on May 20,

the latest in a string of high-profile corporate hacks in the

past year.

In a filing with the U.S. Securities and Exchange

Commission, Live Nation said it found "unauthorized activity" in

a third-party cloud database that mainly contained Ticketmaster

data, and was working with forensic investigators.

Last week a little-known cybercrime group named ShinyHunters

said it had stolen user data of over 500 million Ticketmaster

customers, according to various media reports.

Live Nation did not mention ShinyHunters in its SEC filing.

The company did not respond immediately to a Reuters request

for comment.

The breach comes as the concert promoter has been battling

regulatory scrutiny over antitrust concerns. Live Nation was hit

last week with the first in a likely a wave of consumer

antitrust lawsuits after the U.S. government and states sued to

break up the firm, arguing that along with its Ticketmaster

unit, the company was illegally inflating concert ticket prices.

Live Nation in its filing said that on May 27, "a criminal

threat actor offered what it alleged to be company user data for

sale via the dark web."

"We are working to mitigate risk to our users and the

Company, and have notified and are cooperating with law

enforcement," the company said. "As appropriate, we are also

notifying regulatory authorities and users with respect to

unauthorized access to personal information."

The breach hasn't had and is unlikely to have a material

impact on Live Nation's business or financials, the company

said.

"We continue to evaluate the risks and our remediation

efforts are ongoing," Live Nation said.