Equifax, one of the three major consumer credit reporting agencies, said on Thursday that hackers had gained access to company data that potentially compromised sensitive information for 143 million American consumers, including Social Security numbers and driver’s license numbers.

The attack on the company represents one of the largest risks to personally sensitive information in recent years, and is the third major cybersecurity threat for the agency since 2015.

Equifax, based in Atlanta, is a particularly tempting target for hackers. If identity thieves wanted to hit one place to grab all the data needed to do the most damage, they would go straight to one of the three major credit reporting agencies.

“This is about as bad as it gets,” said Pamela Dixon, executive director of the World Privacy Forum, a nonprofit research group. “If you have a credit report, chances are you may be in this breach. The chances are much better than 50 percent.”