The US Supreme Court rejected Microsoft's appeal to overturn a lower court's ruling that the software behemoth violated antitrust laws, Microsoft confirmed yesterday.

Microsoft spokesman Jim Desler said: "We understood that very few cases are granted for review by the Supreme Court, and we were disappointed that ours wasn't one of the very few."

The US Court of Appeals for the District of Columbia in July of this year upheld a lower court ruling last June that Microsoft violated antitrust rules by holding a monopoly in the PC-operating systems market.

Because the case remains before a lower court, the US District Court, legal experts thought it unlikely that the Supreme Court would take it at this time.

Iowa attorney general Tom Miller said: "The coalition of state attorneys general pressing the suit along with the US Department of Justice are pleased that the Supreme Court declined to take up the Microsoft case." He praised the District of Columbia appeals court decision as "unanimous and very well-reasoned".