Each year the magazine asks firms in the US, Canada, Europe and Asia to count the number of IP practitioners they have according to strictly defined criteria.

Among the criteria are: practitioners must be fully qualified as lawyers or attorneys, and must spend at least 75% of their time on IP work.

Fish & Richardson is the top-ranked firm in the US, with 416 qualifying practitioners, an increase of 24 from last year. The second-biggest firm, Finnegan Henderson, has 339 IP practitioners.

John Gagel, a Fish & Richardson partner, told Managing IP the firm decided to expand geographically about 15 years ago: "That put us in a position to compete with a lot of the general firms that already have thousands of attorneys and offices."

Fish & Richardson now has 10 US offices and recently opened another in Munich. "It's certainly safe to say we're always open to and looking for opportunities," said Gagel.

In Asia seven of the 10 biggest firms are in China. The two biggest are Liu Shen, with 250 practitioners, followed by Shanghai Patent & TM Office with 230.

In Europe, Bird & Bird moved up two places to top the table with 186 practitioners.

See the full article, including the listings of all the largest firms and breakdown by office and an interview with Gagel and Alan Smith of Fish & Richardson, in Managing IP's October issue.