The US Supreme Court has said it will hear an appeal from software company Microsoft over damages relating to a patent dispute with phone firm AT&T.
Microsoft software runs on more than 90% of the world's computers
The dispute centres on accusations that Microsoft infringed an AT&T patent for converting speech into computer code.
According to a lower court decision, AT&T could seek royalties from the foreign sales of Microsoft's Windows programme that infringed the patent.
Winning the appeal could be worth millions of dollars to Microsoft.
The decision will rest on whether or not Microsoft is liable for overseas sales. Both companies reached an agreement over payments relating to domestic sales earlier this year.
Microsoft has acknowledged its liability for domestic sales.