Received this email on Saturday:
Dear mr&mrs:
Bank of America Credit Card has changed your account number. We've already updated your account number in Online Banking to make sure your payments will be credited to the correct account. You don't need to take any action.
If you have any questions about your account, including the reason why your account number changed, contact Bank of America Credit Card directly.
Thank you for using Online Banking.
Per a CS rep in the fraud monitoring department, there was some kind of massive data breach along the lines of a lost laptop or similar. She indicated that replacement cards were mailed last Friday. When we expressed surprise that this was the first we'd heard of any kind of problem -- no warning letter, no robo-call, nothing -- she stated that an explanatory letter would accompany the new cards. When we voiced concern that the new cards would not be received before we leave the country for an absence that will last several months, she stated that the old cards will work until new ones are activated. (When we challenged her on this last assertion, it turned out to be "until the new ones are activated OR until July 12, whichever is sooner."
)
Anyway. Not sure exactly how many cardholders are affected, but the rep did use the term "massive data breach" in her explanation.