Wells Fargo & Co. was accused of overpaying for prescription drugs by former employees, who claim mismanagement of the bank's health plan drove up costs for workers.

A lawsuit filed in federal court in Minnesota Tuesday alleges that the country's fourth-largest bank squandered money in its health plan, sometimes causing workers to pay far more for medications than they would have if they'd paid cash. For example, the Wells Fargo plan paid almost $10,000 for a generic pill for multiple sclerosis that Wegmans pharmacies sold for $648, according to the complaint, driving up premiums and out-of-pocket costs.