It is still not telling the public anything about the scale of the breach. Disclosure rules are a mess.
MGM has resorts in Las Vegas, Atlantic City and Detroit in the US. It also has property in China and Japan and is developing a new resort in Dubai.
Most US states do not require companies to tell customers if data which is already public has been exposed during a hack.
MGM knew the scale the hack since last summer.
It appears they CHOSE not to correct reports.
Among the people who were impacted included celebrities like Justin Bieber and Twitter founder Jack Dorsey. 1,300 former guests were notified that more sensitive information including passport numbers had been revealed.
In 2017, Marriott Hotels experienced a much larger data breach exposing 500 million guests. That attack was linked to Chinese state-sponsored hackers.