https://www.theguardian.com/technology/2017/oct/03/yahoo-says-all-of-its-3bn-accounts-were-affected-by-2013-hacking

The company said last December that data from more than 1bn user accounts was compromised in the largest breach in history, but is now tripling that figure

Yahoo said on Tuesday that every one of its 3bn accounts were affected by a 2013 data theft at the tech company, tripling its earlier estimate of the largest breach in history.