Exclusive: Orrick and Pillsbury in talks to form top 10 U.S. law firm

Two top U.S. law firms are in advanced merger discussions to create one of the 10 largest in the country, according to the firms' chairmen.

San Francisco-based Orrick Herrington & Sutcliffe is expected to sign a letter of intent next week to join with Pillsbury Winthrop Shaw Pittman, a source with direct knowledge of the discussions said.

Pillsbury Chairman James Rishwain and Orrick Chairman Mitch Zuklie issued a joint statement to Reuters that said: "Our firms are in exploratory discussions about a possible combination. These talks are serving to confirm the great respect our firms have for each other."

(Reporting by Casey Sullivan; Editing by Kenneth Barry)