One of Herbert Smith's favoured US firms, Winthrop Stimson Putnam & Roberts, is merging with a San Francisco practice to create a nationwide giant.
New York firm Winthrop Stimson is in the final stages of talks with San Francisco's Pillsbury Madison & Sutro in a bid to build a 900-lawyer partnership with 16 offices worldwide.
The new firm will be called Pillsbury Winthrop, but the merger will not be voted on by the partners until October, and is expected to come into effect at the end of the year.
Both firms have strengths in capital markets, M&A, finance and litigation. Herbert Smith and Winthrop Stimson have made a number of referrals to each other on litigation matters.
The New York firm also has a 10-lawyer London office and practices in Tokyo, Singapore and Hong Kong.
Winthrop Stimson chairman John Pritchard, who will be vice chairman of the new firm, says: "About a year ago we started out on a strategic process to identify a merger. Merging with Pillsbury accomplishes the original goal that we set for ourselves, which was to strengthen our core practices.
He says the merger will not affect the firm's relationship with Herbert Smith, which he emphasises is not a formal best-friends link-up. However, he adds that the newly created practice will want to expand rapidly in London and Asia, before considering continental Europe as its next step. He says an English merger partner has not been ruled out, as both firms have had merger talks in the City before.
Chris Parsons, Herbert Smith's head of Italy, with responsibility for the international network, says: "It doesn't really im-pact on us what they are doing. It's a firm that we know well so we hope that it works out for them."