A supreme screw-up brings us this week’s Marketplace Money buzzword: ERISA.

It stands for Employee Retirement Income Security Act. Among other things, this law lets you sue if something in your retirement plan goes awry.

That’s what James LaRue did after he asked his 401(k) managers to move his money into safer investments. They didn’t do it and LaRue wound up losing $150,000.

Whoops!

This week, the Supreme Court unanimously decided that, under ERISA, individual investors can sue their fund managers for such blunders.

Now the managers will have to invest… in a team of lawyers.