In a bitter whistleblower fight that pitted Bill Koch against his brother Charles, the chief executive of Koch Industries, a jury has found that the oil company deliberately cheated oil producers–a verdict that could cost the nation’s second-largest privately held company as much as $214 million.

Plaintiff Bill Koch alleged that the family company falsified measurements in the field, stealing millions of barrels of oil from producers and royalty owners on mostly federal and American Indian-owned land. The suit was filed under the False Claims Act, meaning that Bill Koch and his co-plaintiff, Bill Presley, stand to gain up to 30% of the court award. Neither the government nor the Indians joined the suit, but the balance will go to the government.