2016 — Yahoo: Happened in 2014, but no, 500.0M records 2016 500.0M records affected Share on X Technical writeup Sep 2016. Happened in 2014, but no. records stolen was originally thought to be much smaller. Yahoo revealed the real numbers in 2016. Root cause Hacked Referenceshttp://uk.businessinsider.com/yahoo-hack-by-state-sponsored-actor-biggest-of-all-time-2016-9?r=US&IR=T