For Retirement Savers, Even Minor Cyber Intrusions Pose Big Risk

A public pension fund serving more than 200,000 current and former Missouri educators was compromised last month when an employee’s email account was hacked.

The data breach in Missouri lasted less than an hour, and no personal or financial information of the workers and retirees was stolen. But it was the latest in a series of high-profile intrusions involving local governments and major U.S. corporations that highlight the emerging threat cyber vulnerabilities pose for retirement plan participants and their beneficiaries as more of their information is stored online.

The U.S. Labor Department and major financial institutions have doubled down on ...