Pillsbury Winthrop Shaw Pittman LLP and Orrick Herrington & Sutcliffe LLP said they are in talks about merging the San Francisco-based law firms, Bloomberg News reported on Friday. According to trade publication The American Lawyer, Orrick, a 977-lawyer firm, had $866 million in gross revenue last year, making it the 27th wealthiest firm in the country. Pillsbury, with 609 lawyers and $561 million in gross revenue last year, was ranked 56th in terms of wealth, according to The American Lawyer rankings. U.S. law firms have entered 58 mergers so far this year, compared to 60 in all of 2012, according to legal consultant Altman Weil Inc.’s MergerLine.