US firms Buchanan Ingersoll and Klett Rooney Lieber & Schorling are to merge. The new practice, which will be known as Buchanan Ingersoll & Rooney, will have an annual turnover of $265m (£144m) and 525 lawyers.

The deal, which is expected to be completed on 1 July, comes a year after Philadelphia-based Buchanan acquired US intellectual property specialist Burns Doane Swecker & Mathis.