The country’s largest credit union will pay up to $25 million for improper optional overdraft protection fees under a class action settlement that a federal judge in San Diego preliminarily approved on Oct. 22.

Judge Cynthia Bashant of the U.S. District Court for the Southern District of California gave her initial sign off on a deal that will see Navy Federal Credit Union pay $24.5 million to settle claims that it charged improper overdraft protection fees on debit card charges....