Supreme Court Chief Justice John Roberts has sold between $250,000 and $500,000 worth of Microsoft stock, according to an Associated Press report out today. It's the largest single stock sale by anyone on the court in more than a decade.

The large stock sale is news in part because the high court agreed a few weeks ago to take a case involving alleged defects in Microsoft's Xbox 360 console. Assuming that Roberts sold all his Microsoft stock, that means he won't have to withdraw from the case.

The last time Microsoft had a case in front of the Supreme Court was 2011, in which the software giant made a last-ditch attempt to fend off a patent claim brought by i4i, a small Canadian firm. Microsoft asked the court to reconsider the standard of proof used to invalidate patents, but the justices sided with i4i in an 8-0 vote, cementing the firm's $290 million payday. Roberts recused himself from that case.

Only three justices—Samuel Alito, Stephen Breyer, and Roberts—own individual stocks. It's become a tangled ethical issue. In recent months, Alito has had to sit out a case involving a subsidiary of Johnson Controls Inc. Alito owns up to $15,000 of Johnson Controls stock. After a call from a Bloomberg reporter, Breyer realized his wife owned about $33,000 of Johnson Controls. She quickly sold the stock, and Breyer will sit on the case.

Roberts also owns between $100,001 and $250,000 in Texas Instruments stock. He voted to deny an appeal by Texas Instruments in October. A court spokeswoman told AP that Roberts shouldn't have been involved in that vote.

In all, the chief justice owns about a dozen individual stocks, including $250,000 to $500,000 in Time Warner.

The assets of Supreme Court justices are made public through disclosure forms, which include ranges rather than exact values.