The runner-up spot this week goes to a team led by Allan Arffa of Paul, Weiss, Rifkind, Wharton & Garrison that got a big appellate reversal for data analytics company Mu Sigma Inc., and its founder and CEO, Dhiraj Rajaram in a long-running lawsuit brought by Walworth Investments. This week the Illinois Supreme Court unanimously reversed an intermediate appellate court that had reinstated fraud and breach of fiduciary duty claims tied to Walworth’s 2010 sale of its stake in Mu Sigma. Walworth had been seeking nearly $650 million in damages claiming Mu Sigma misled it into selling its stake in the company for less than it was worth. The state’s high court, however, found that the underlying repurchase agreement “considered as a whole, reveals a clear disclaimer of reliance by the plaintiff on extracontractual statements made by the defendants.” Arffa argued the appeal before the Illinois Supreme Court. The team representing Mu Sigma also included Paul Weiss partner Jeffrey Recher, and counsel Robert Kravitz, with input from partner Andy Bouchard, who joined the firm last year after serving seven years as Chancellor of the Delaware Court of Chancery. John Dwyer, Martin Schenker and Tijana Brien of Cooley, and James Figliulo and Peter Silverman of Smith, Gambrell & Russell were co-counsel for Mu Sigma.

Shout out to Nessa Coppinger and Jayni Lanham of Beveridge & Diamond who won a ruling late last month for 3M striking down a new Michigan rule limiting the level of PFAS—often referred to as “forever chemicals”—in drinking water and groundwater. Judge Brock Swartzle of the Michigan Court of Claims found that the state’s Department of Environment, Great Lakes, and Energy failed to consider the costs the new rule imposed on 3M and other similarly situated companies as required under the state’s Administrative Procedures Act. The court, however, stayed the effect of its ruling to allow for appellate review or further regulatory action.