Yahoo says Marissa Mayer faced 'specific security threats' throughout 2015

Yahoo had to pay more than half a million to protect its CEO from "credible" security threats, the company disclosed in its SEC filing.

Compared to other tech CEOs, Yahoo has never paid much in personal security expenses for its executives.

In 2014, Yahoo attributed $26,891 costs for Mayer's security at business events and business travel. That's less than even Intel's CEO ($36,000) and leagues below the $1.6 million Amazon pays for Jeff Bezos' security.

2015 was different though.

Mayer's security costs jumped from nearly $27,000 to $544,061 for 2015. Yahoo attributed the dramatic increase to the fact that Mayer "faced specific security threats that we believed were credible," the company said in the filing.

Yahoo didn't immediately respond to request for comment.