SAN FRANCISCO — As the Howrey estate rakes in settlements, a handful of firms are still trying to tear down a controversial bankruptcy doctrine that has vexed the legal industry for years.

Six firms that hired former Howrey partners urged U.S. Bankruptcy Judge Dennis Montali of the Northern District of California at a hearing on Wednesday to dismiss the claims filed against them by the now-defunct firm’s bankruptcy trustee, Allan Diamond. Suing under the unfinished business doctrine, Diamond seeks to recover profits from the work that former Howrey partners brought with them to their new firms, arguing that it is property of the estate.