Live Nation is investigating a data breach at its Ticketmaster subsidiary, which dominates ticketing for live events in the United States.

Live Nation, based in California, said in a regulatory filing Friday that on May 27 “a criminal threat actor″ offered to sell Ticketmaster data on the dark web. Other media reports say a hacking group named ShinyHunters claimed responsibility for the breach in an online forum and was seeking $500,000 for the data, which reportedly includes names, addresses, phone numbers and some credit card details of customers.

In a filing with the Securities and Exchange Commission, Live Nation said it was “working to mitigate risk to our users” and was cooperating with law enforcement officials.

On May 23, the Justice Department sued Live Nation and Ticketmaster, accusing them of running an illegal monopoly over live events in America.

Vermont has become the first state to enact a law requiring fossil fuel companies to pay a share of the damage caused by climate change after the state suffered catastrophic summer flooding and damage from other extreme weather.

Republican Gov. Phil Scott allowed the bill to become law without his signature late Thursday. Scott wrote in his message to lawmakers that taking on ‘Big Oil’ should not be taken lightly and that he is concerned about the costs and outcomes of the small state doing that alone. Maryland, Massachusetts and New York are considering similar measures.