The company says
The investigation has shown the hackers may have stolen additional personal data and we are notifying the holders of 77,000 payment cards, not previously notified, that the name, billing address, email address, card payment information, including card number, expiry date and CVV have potentially been compromised, and a further 108,000 without CVV. The potentially impacted customers were those only making reward bookings between April 21 and July 28, 2018, and who used a payment card.
While we do not have conclusive evidence that the data was removed from British Airways’ systems, we are taking a prudent approach in notifying potentially affected customers, advising them to contact their bank or card provider as a precaution. Customers who are not contacted by British Airways by Friday 26 October at 1700 GMT do not need to take any action.
In addition, from the investigation we know that fewer of the customers we originally announced were impacted. Of the 380,000 payment card details announced, 244,000 were affected. Crucially, we have had no verified cases of fraud.