US firm Kilpatrick Stockton has agreed to merge with San Francisco's Townsend and Townsend and Crew, creating a $400m (£250m) practice, reports The Am Law Daily.

The combined 650-lawyer firm, which will be named Kilpatrick Townsend & Stockton, will officially launch on 1 January next year, and will have 17 offices throughout the US. The two firms pursued a possible union earlier this year, but called off the talks in July, citing client conflicts.

Townsend, which specialises in intellectual property (IP) work, has been looking for a merger partner for some time. Last December, chairman James Gilliland stepped down amid a slowdown in two of the firm's strongest practice areas – litigation and patent prosecution.

Once the merger takes effect, Kilpatrick comanaging partner William Dorris will become chair of Kilpatrick Townsend. Former Kilpatrick comanaging partner Diane Prucino and Townsend's Sheehy will serve as co-managing partners of the newly combined firm.

"From IP to corporate to litigation, Kilpatrick Townsend clients will have access to a diverse group of nearly 650 lawyers with the resources to offer clients expanded, strategic expertise," Dorris said in a statement.

The Atlanta-based Kilpatrick posted gross revenue of $246m (£152m) and profits per partner of $615,000 (£379,000) in 2009, while Townsend's profits per partner stood at $810,000 (£500,000), with turnover at $161m (£100m).

The merger is the latest in a busy year for law firm tie-ups, in particular transatlantic deals. Sonnenschein Nath & Rosenthal and Denton Wilde Sapte officially merged last month to create SNR Denton, while Hogan & Hartson completed its merger with Lovells in May to form Hogan Lovells, and Squire Sanders & Dempsey and Hammonds currently are discussing a possible combination.

The Am Law Daily is a blog on law.com, Legal Week's US affiliate title.