An attempt by former Washington Mutual Inc. employees to recoup their retirement account losses from JPMorgan Chase & Co., part of a complex tangle of litigation stemming from WaMu’s collapse last year, has been dismissed.

Some former WaMu directors and individuals who served on 401(k) fund committees remain partly on the hook, but the New York banking giant cannot be held liable for mismanagement that may have occurred before the Federal Deposit Insurance Corp. seized what was once the nation’s largest thrift because of bad housing loans, U.S. District Judge Marsha J. Pechman ruled Monday.