The suit says VW failed to disclose to U.S. investors that its "clean diesel" cars were exceeding vehicle emissions limits.
The automaker is in "advanced discussions" over an agreement that would further extricate it from the diesel emission cheating scandal.
"The emission crisis might cause lasting damage to VW’s once-solid reputation with adverse effects on its future earnings and cash flows," says Moody's.
The agency says software installed in nearly half a million diesel cars enabled them to pass emission standards.
