A federal judge on Monday stepped down from overseeing a lawsuit filed by Amazon after it was learned his wife owned stock in the company.

U.S. District Judge Liam O’Grady disclosed recently that he learned his wife had $22,000 of stock in Amazon while he was assigned to a case the e-commerce giant brought against a Colorado real estate developer and a former Amazon employee alleging a kickback scheme. The revelation came following a Wall Street Journal investigation.