The suit sought to recover alleged financial losses suffered by the 401(k) plan, and to obtain injunctive and other relief.

The plaintiffs, led by named plaintiff Glenn Tibble, sought recovery under ERISA against SCE's parent company, Edison International; the Edison International Trust Investment Committee; the SCE Benefits Committee; and SCE's vice president of human resources, among others, for alleged breaches of their fiduciary duties.

The plan, a defined contribution 401(k) savings plan, was started in 1982 and was maintained for all employees of Edison-affiliated companies.

Participants' retirement benefits are limited to the value of their own individual investment accounts, which is determined by market performance of employee and employer contributions, less expenses.

The problem was a group of 17 mutual funds selected by the defendants in March of 1999 as investment options for the plan.

In each case, the defendants either initially chose the more expensive retail shares instead of the cheaper institutional class, or did not switch to institutional class when they became available.

Except for the expense ratio, including revenue sharing, the retail share class and institutional share class are managed identically, and the plaintiffs contended that the defendants breached their duty of prudence by not switching from retail to institutional in all 17 cases.

Before those 17 funds were added in 1999, SEC paid for the costs of the plan's recordkeeper, Hewitt Associates LLC, which provided services including mailing prospectuses, mailing individual account balances, providing participant statements, operating a website accessible by plan participants and answering inquiries from plan participants regarding their investment options.

However, when the funds were added, certain revenue sharing was made available to SCE through the retail shares that could be used to offset the cost of Hewitt Associates' recordkeeping expenses.

The use of revenue sharing to offset Hewitt Associates' recordkeeping costs was discussed with the employee unions during the 1998–99 negotiations, and the arrangement was disclosed to plan participants on approximately 17 occasions after the practice began in 1999.

The class action was filed on August 16, 2007, gaining class certification in June of 2009, but the defendants sought summary judgment in May of 2009, and it was granted in part by the court.

Among other things, the court ruled that some of plaintiffs' aims were barred by the statute of limitations mandated by ERISA Section 1113. This section imposes a six-year statute of limitations, which, the court ruled, barred claims relating to events occurring before Aug. 16, 2001.

Funds added in 2001, however, the court found, should have been added in institutional class, not retail class; it also found a pattern of choosing funds with reduced revenue sharing.

On appeal, the U.S. Supreme Court found that the lower court erred in not considering the nature of fiduciary duty when it ruled against the plaintiffs, and when the suit returned to the district court, it found that the defendants were not reasonably prudent in their choices of retail shares.

The profits that the plan would have accrued with institutional shares from March 1999 through January 2011 were $7,524,424; the court also determined that additional damages were available since January 2011 based on the plan's overall returns during that time, as well as finding that the plaintiffs were potentially entitled to their attorney fees.

In short, HR representatives have to be sure they're looking after all employee interests, even in the matter of administrative fees.