One billion accounts is far and away the biggest data breach yet reported from a single source.
Below is a rundown of some of the biggest data breaches, according to the database maintained by the Privacy Rights Clearinghouse.
The data, which was stolen by what the company called a "state-sponsored actor," may have included names, passwords, emails, telephone numbers, dates of birth and security questions and answers, the company said, but not financial information.
The breach dated to 2014 and was discovered in August when a group of hackers was discovered trying to sell information for 200 million accounts on the internet.
Sometime before June 2013, the once-popular social networking site My Space was attacked.
It wasn't until May 2016 that the company (then owned by Time) reported that 360 million accounts, with user names, passwords and emails, were for sale in an online hacker forum.
At the time, that attack was regarded as the largest-ever single-source data hack in history.
Then on Wednesday, the company announced a second hack that more than doubled the record.Heartland eventually paid about 0 million in fines and penalties for the data breach, and an American hacker was sentenced to 20 years in prison for his role in the attack.Note: In order to integrate a email account, login must be successful on the Yahoo! If the Verizon webmail login is successful, but logging into Yahoo!It's unclear how many of the 1 billion accounts were also part of the earlier attack.The compromised accounts came to light after an unidentified third party gave law enforcement officials data files they claimed contained Yahoo user information.Security experts said that criminals would be able to use that information for more old fashioned scams over the phone.