America’s largest insurer is facing two purported class-action suits from former employees alleging the company misused their 401(k) contributions.

The latest suit, filed Wednesday in federal court in Minnesota, claims that UnitedHealth Group held on to employees’ money after they left and used it to improperly lower its own costs, the plaintiffs argue. The move is a breach of UHG’s duty to act in the best interests of its retirement plan participants—ie, the current and former workers invested in its 401(k) plan.

As the suit describes it, UHG, which took in $400 billion in revenue last year, has a fairly standard corporate 401(k) plan, contributing up to 4.5% of employees’ pay under certain conditions. However, employees forfeit the money UHG contributed to their plan if they leave before completing two years with the company. 

Between 2019 and 2023, UHG used $19 million in forfeited funds to reduce its own matching contributions, instead of using it to reduce administrative fees for the 401(k) accounts. That was a breach of UHG’s fiduciary duty to plan participants, the plaintiff argues.

A “prudent fiduciary in like circumstances would have defrayed expenses to the Plan’s participants rather than defray costs to the employer,” says the lawsuit, claiming UHG caused “participants to incur millions in expenses that could otherwise have been covered in whole or in part by forfeited funds.” In not acting in plan participants’ best interests, UHG violated the Employee Retirement Income Security Act (ERISA), the suit claims. It is seeking class-action status. 

UHG’s 401(k) plan has $22 billion in assets and counts 267,000 participants, according to Department of Labor documents.

“Our 401(k) plan fiduciaries have always acted in accordance with ERISA and in the best interests of plan participants, and we strongly deny any allegations to the contrary,” a company spokesperson said in a statement. “We will move to dismiss at the earliest opportunity.”

Last year, UHG paid $69 million to settle claims that fund selections in its 401(k) plan underperformed the market. 

It’s also facing a number of lawsuits relating to its provision of health care. CalPERS, the California state retirement system, has sued UHG claiming the insurer illegally “upcodes” Medicare Advantage treatments, making patients seem sicker than they are, an allegation of massive fraud that is also subject to a federal Department of Justice investigation. Families of patients who died are suing UHG, alleging the company relied on an AI algorithm to deny care, and shareholders have sued in connection with UHG’s reaction after the killing of CEO Brian Thompson. 

Correction, June 2, 2025: A previous version of this story misstated the amount of UHG’s contribution described in the lawsuit.