The issues concerning Yale’s 403(b) retirement plan — which held nearly $3.6 billion in assets in the spring of 2014 — follow a similar pattern: multiple record keepers with excessive fees, costing participants millions of dollars over the last six years; too many investments of the same style; and the use of higher-cost funds instead of identical but lower-priced ones. That case was filed in Federal District Court in Connecticut.

Yale eventually consolidated to one provider, TIAA, in April 2015, and swapped in some lower-cost investments, but the suit claims that the changes did not go far enough to fully protect the interests of its employees. Mr. Schlichter said participants were still burdened with sorting through more than 100 options, many of which were too expensive.

The complaints lodged against M.I.T.’s retirement plan (unusually, it is a 401(k) like those used by corporations) are similar but with a twist.

The suit alleges that the university, because of its longstanding relationship with nearby Fidelity, did not conduct a thorough search for a plan provider, which might have provided better service for less. The retirement plan offered more than 340 investment options — including 180 Fidelity funds — until July 2015, when M.I.T. reduced the lineup to 37 options but still retained Fidelity as the record keeper.

The complaint said that Fidelity had donated “hundreds of thousands of dollars” to M.I.T., while Abigail Johnson, Fidelity’s chief executive, has served as a member of M.I.T.’s board of trustees, giving her influence over the institution’s decision-making.

Had the plan reduced its options to those on the menu it adopted last year, “participants would have saved over $8 million in fees in 2014 alone, and many millions more since 2010,” according to the complaint, filed in Federal District Court in Massachusetts. M.I.T. recognized that the plan structure was inefficient, the filing said, since that was part of the reason it said it made the changes. But even after the overhaul, the suit alleges, investment costs could be further reduced.

Fidelity, which noted that it was not a defendant in the case, declined to comment.

Mr. Schlichter’s firm has settled about half of his 20 cases over the last 10 years. His first case involving a 403(b) was against Novant Health, a nonprofit hospital system, which settled last year for $32 million. In a landmark case he argued last year before the Supreme Court, the justices, in a unanimous decision, agreed that plan sponsors had a “continuing duty to monitor investments and remove imprudent ones.”