ChicagoDallas firm Jenkens & Gilchrist is squaring up for a high-profile court battle over client privilege with the US’ Internal Revenue Service (IRS) in the latest attempt to force US lawyers to disclose client information to federal authorities.

The row comes after the IRS, on 19 June, obtained permission from a Chicago court to summon lawyers from Jenkens to reveal the names of up to 600 clients of its tax practice as part of a bid to clamp down on tax havens. Jenkens, which has pledged to fight the summons, has hired McDermott Will & Emery and Levin-Ginsburg to represent it.