A new report by congressional investigators details how hackers broke into Equifax last year in a breach that exposed the financial information of more than 145 million Americans.

The lawmakers who requested the report say they will press the Trump administration on the lack of enforcement actions against the giant credit-reporting agency.

Shares of Equifax plunged by about one-third last year after news broke about the massive breach. Since then, the stock has recovered to about $10 below its peak before all the bad news and closed Friday at $135.91 a share. The company has reported a profit...