SAN FRANCISCO — The Howrey estate has slapped three more law firms with unfinished business claims — an important source of recovery for bankrupt firms and a headache for many solvent ones.

Jones Day, Hogan Lovells and Pillsbury Winthrop Shaw Pittman were the latest firms targeted by the now-defunct law firm on Friday. Howrey bankruptcy trustee Allan Diamond has now filed suit against 17 firms that hired Howrey partners as the firm was collapsing, arguing that the profits from the work the lawyers brought with them belong to the estate.