At the end of last year, Glenn Tibble's long-standing claim against Edison International regarding excessive 401(k) fees was given an opportunity to continue by the U.S. Circuit Court of Appeals for the Ninth Circuit. The primary issue in that case (the first regarding excessive 401(k) fees to be heard by the Supreme Court) was a procedural one, but the court also discussed two substantive areas of law under the Employee Retirement Income Security Act of 1974 that's of interest to investment advisers: the duty to monitor and the duty of a prudent trustee to be cost-conscious.

http://www.investmentnews.com/article/20170411/BLOG09/170419986/advisers-should-heed-fiduciary-principles-in-ongoing-tibble-401-k