Billionaire Phil Anschutz and his wife are suing Colorado for a tax refund. How much they want is a secret.

Colorado billionaire Phil Anschutz and his wife, Nancy, are suing the Colorado Department of Revenue for a tax refund in a case that could have big financial consequences for the state.

The couple argue that due to changes to federal tax law made as part of Congress’ 2020 pandemic response bill, the CARES Act, Colorado’s tax law was changed as well, allowing him and his wife to claim a refund on their 2018 state income tax bill.

But lawyers with the Colorado Attorney General’s Office, which is representing the Department of Revenue in the case, argue the Anschutzes are pushing an unreasonable interpretation of Colorado’s tax laws, and are asking a judge to dismiss the lawsuit. The state’s lawyers also argue that if the court sides with the Anschutzes, it could sow fiscal chaos in how the state collects and refunds tax revenue.

The Anschutzes’ complaint launching the lawsuit, filed April 5 in Denver District Court, is under wraps after the judge in the case, J. Eric Elliff, granted a protective order on June 1 barring public access to the document and other information contained in court filings.