Fresh off a May trial win of $800 million for the Federal Housing Finance Agency, Quinn Emanuel Urquhart & Sullivan is facing congressio­n­al scrutiny over its role in helping another government entity, the Internal Revenue Service, pursue an audit of Microsoft Corporation.

In a May 13 letter, Senate Finance Committee chair Orrin Hatch asked IRS commissioner John Koskinen to “immediately halt the use of [Quinn Emanuel] for both the examination of records and the taking of sworn testimony” from Microsoft. The Utah senator’s letter, which accuses the IRS of violating federal law and “the express will of Congress,” expands a court battle over the Microsoft audit into the political realm.