Yahoo! (Over 3 billion, September 2016)

Still holds the record for the largest data breach in history. Yahoo was acquired by the company Verizon in July 2016 and it was the victim of multiple major hacks after that. It exposed the names, email addresses, telephone numbers, date of births and other valuable information of over a billion people who used Yahoo.

Yahoo told the public that, it experienced a breach in 2014, which affect almost 500 million accounts. Later, in December another one happened on its network, which exposed at least one billion user accounts. The United States indicated four men, including two employees of Russia’s Federal Security Service for their involvement in this attack.