Minority investors in West Palm Beach-based Oxbow Carbon, fresh off a major Delaware Court of Chancery victory, are investigating up to $50 million in payments made by the company to attorneys for founder and CEO William Koch at Mintz, Levin, Cohn, Ferris, Glovsky and Popeo.

Robert J. Hurst and Barry Volpert, principals in Crestview-Oxbow Acquisition LLC, said in a books-and-records complaint Wednesday that they were targeting ”corporate waste and inappropriate spending” on Mintz Levin, claiming the law firm served Koch's interests despite agreeing to represent Oxbow in a two-year suit over Crestview's right to force Oxbow's sale.

Last month, Vice Chancellor J. Travis Laster appointed a receiver to oversee an auction of the company, and he ordered Koch, the brother of billionaires and conservative political activists Charles and David Koch, to pay tens of millions of dollars in damages to Crestview and its affiliate Load Line for derailing a deal to sell the Oxbow in 2016.

In his ruling, Laster concluded Koch initially hired Boston-based Mintz Levin to serve as his personal counsel but later modified the firm's engagement letter so Mintz Levin represented Oxbow. Oxbow Carbon promotes itself as one of the world's largest recyclers of refinery and natural gas byproducts.

“I personally believe Koch wanted Oxbow's counsel to be loyal to him, liked the idea that Mintz Levin would be in a position to run Oxbow's internal investigations into Koch's perceived adversaries, and understood that the minority members would effectively pay one-third of Mintz Levin's fees,” Laster wrote in an Aug. 1 decision.

Hurst and Volpert, who have served as Oxbow directors since Crestview first invested in the company in 2007, said in their complaint that Koch had a history of using Oxbow as “his own personal ATM” and used company resources to fund at least some of the costs of a “lavish, celebratory post-trial vacation” for Mintz Levin attorneys at the Chatham Bars Inn on Cape Cod. Current room rates start at $359 a night.

The purpose of their books-and-records suit, they said, was to identify any other alleged sources of corporate waste and to determine whether the Oxbow board took any steps to remedy potential breaches of fiduciary duty.

Hurst and Volpert said Koch's personal attorneys admitted Oxbow paid Mintz Levin more than $31 million over three years while the firm was advancing Koch's personal interests. However, they alleged Oxbow and lawyers for Koch refused to turn over any documents supporting that figure. The actual cost, Crestview estimated, could be as much as $50 million based on amounts reflected in Oxbow's financial statements for “certain items.”

“Plaintiffs are unable to determine the amount or justification for the company's spending on Mintz Levin or spending otherwise related to the exit sale litigation,” attorneys from Quinn Emanuel Urquhart & Sullivan wrote in the 21-page complaint.

“But whether the total amount of spending is $31 million or $50 million or more, the fact is that Mr. Koch chose to have Oxbow bear the costs of this spending rather than pay them himself. As a result, Crestview and Load Line 'indirectly bore one-third of the estimated' costs that Mr. Koch forced Oxbow to incur to litigate against Crestview and Load Line.”

Hurst and Volpert are represented by Michael B. Carlinsky, Chad Johnson, Jennifer Barrett and Silpa Maruri of Quinn Emanuel in New York.

An online docket-tracking service did not list counsel for Oxbow.

The case is Crestview-Oxbow Acquisition v. Oxbow Carbon.