Jennifer Keller, the attorney who won an $88.5 million verdict against Mattel Inc. in the battle over the Bratz doll, has teamed up with three former partners at Manatt, Phelps & Phillips to create a new firm based in Irvine, Calif.

Keller now represents Standard & Poor’s Financial Services LLC in defending claims by the U.S. government that it inflated the ratings on various mortgage-backed securities just before the 2008 financial crisis. On Thursday, she combined her firm, Keller Rackauckas, with Thomas Umberg and Dean Zipser of Manatt to create Keller Rackauckas Umberg Zipser LLP.