The US Supreme Court sided with Microsoft yesterday, agreeing with the giant software company that its appeal of antitrust violations should first be heard by a lower appellate court.

Microsoft, appealing an order that it be split in two for violating antitrust law, had asked the court to let the case be heard first by the Court of Appeals. But the Justice Department argued for a speedy decision directly from the high court, which has never ruled on the case.

Some in the industry say its technology is moving so quickly that by the time the case is over it will be irrelevant, because emerging technology will challenge the dominance of the Windows PC.

But others, including the Justice Department, say they are concerned that Microsoft will have more time to solidify its dominance of new technologies.

Significantly, the appeals court that will hear the case ruled for Microsoft on a related matter in 1998. The appeals court has already shown it is eager to take the case, announcing on June 13th it would have its full bench consider the matter rather than the usual three-judge panel.

Among the Supreme Court's nine members, only Justice Stephen Breyer dissented, saying the case "significantly affects an important sector of the economy - a sector characterised by rapid technological change. Speed may help create a legal certainty".

The ruling sent Microsoft's shares up $2-3/4 (€3.12) to $64 in heavy trading by early afternoon. The share price dropped from a high of $119-15/16 to $60-3/8 after adverse trial court rulings earlier this year.

Microsoft chief executive officer Steve Ballmer appeared on television within minutes of the announcement to express his delight. "We're glad to have a chance to present that (our position) to the appellate court." Mr Kevin Dillon, managing director of the European operations centre at Microsoft Corporation, based in Dublin, said the company's legal team believed the court of appeals was better suited to hear a case of this type.