Microsoft has been banned from selling its Word software package in the United States after a judge ruled it infringes on patents owned by a company called i4i. The Redmond firm has also been ordered to pay $290m in damages.

The row centres on patents filed by Toronto, Canada-based i4i in 1998 concerning the reading of XML programming, which enables Word to read and write .XML, .DOCX, or DOCM files.

Judge Leonard Davis of the US District Court for the Eastern District of Texas ordered Microsoft to pay $290m in damages to i4i, including $40m for the wilful infringement of the patent and $37m in pre-judgment interest. The company also has to pay $21,000 per day until a full settlement is reached.

Microsoft has also been banned from selling Word in the US or importing the software into the country. It has 60 days to comply with the ruling.

According to a report in the Telegraph, Microsoft would be appealing the decision. “We are disappointed by the court’s ruling,” said Kevin Kutz, a spokesman for the software giant. “We believe the evidence clearly demonstrated that we do not infringe and that the i4i patent is invalid.”