NEW YORK (AP) -- Yahoo says it believes hackers stole data from more than one billion user accounts in August 2013.
The Sunnyvale, California, company says it's a different breach from the one it disclosed in September, when it said 500 million accounts were exposed. That new hack revelation raises questions about whether Verizon will try to change the terms of its $4.8 billion proposed acquisition of Yahoo.
Yahoo says the information stolen may include names, email addresses, phone numbers, birthdates and security questions and answers. The company says it believes bank-account information and payment-card data were not affected.
The new hack revelation raises fresh questions about Verizon's $4.8 billion proposed acquisition of Yahoo, and whether the big mobile carrier will seek to modify or abandon its bid. If the hacks cause a user backlash against Yahoo, the company's services wouldn't be as valuable to Verizon. The telecom giant wants Yahoo and its many users to help it build a digital ad business.
In a statement, Verizon said that it will evaluate the situation as Yahoo investigates and will review the "new development before reaching any final conclusions." Spokesman Bob Varettoni declined to answer further questions.
Yahoo said Wednesday that it is requiring users to change their passwords and invalidating security questions so they can't be used to hack into accounts.