Equifax is plunging after announcing a massive security breach

Equifax is getting slammed in premarket trading on Friday, down 13.82%, after the company revealed a massive data breach.

Following Thursday's closing bell, the company announced the personal details, including names and social security numbers, of more than 143 million customers were potentially accessed by hackers between mid-May and July. Additionally, Equifax said that credit card numbers for about 209,000 people, and certain documents for another 182,000 were also accessed.

Three senior executives at the company dumped $2 million worth of stock days after the company learned of the data breach. An emailed statement from the credit-monitoring agency said that the executives "had no knowledge" of the breach beforehand.

Premarket selling has shares back at levels last seen in February. Equifax shares are up more than 4% this year, including Friday's slide.

Equifax Markets Insider