Approximately 500 million customers of Marriott, which includes brands such as W, Sheraton, and Westin, Marriott, have had their data hacked. 

The Company has confirmed that customer names, addresses, passport numbers, dates of birth, and other information has been stolen. Credit card information has also been stolen and, though encrypted, there are fears that the hackers may be able to decrypt it. 

Arne Sorenson, Marriott's president and CEO, said: "We deeply regret this incident happened."

It will be interesting to see the reaction from regulatory authorities as to the measures that have been put in place, particularly as this breach dates back to 2014 and may have been on-going for a number of years.