Wed Mar 1, 2006 02:00 PM ET

By Peter Kaplan

WASHINGTON (Reuters) - The Supreme Court on Wednesday handed a legal victory to patent-holding companies, making it easier for them to tie the sale of their patented products to other products they sell.

The high court reversed a decades-long legal doctrine that had made it easier to sue companies for illegally tying such products together under U.S. antitrust law by assuming a patent gave them monopolistic power.

The case grew out of a lawsuit filed by a small California ink company called Independent Ink, which alleged a subsidiary of Illinois Tool Works Inc. had illegally required buyers of its patented printheads to also use its ink to fill them.

In Wednesday`s ruling, the justices remanded the printer ink case back to a lower court, saying Independent Ink would have to prove Illinois Tool had market power in order to prevail.

The high court said in its ruling that ``because a patent does not necessarily confer market power upon the patentee, in all cases involving a tying arrangement, the plaintiff must prove that the defendant has market power in the tying product.``

Illinois Tool had prevailed in District Court where a judge threw out the case. But the U.S. Court of Appeals for the Federal Circuit partly reversed that judgment, citing the precedent that holding a patent automatically confers market power.

Fallout from the ruling goes beyond the ink business.

Illinois Tool`s challenge to the high court was supported by companies and trade groups from the pharmaceutical and media industries, including Pfizer Inc., the Motion Picture Association of America and even the National Football League.

But the challenge was opposed by some consumer groups, who feared it could lead to higher prices, particularly in the market for replacement parts.

``This will encourage companies that have patents to exploit them through tying conditions,`` Bert Foer, president of the American Antitrust Institute, said after the high court ruling.

The court`s ruling did not address the request by the Motion Picture Association, which said the ruling should extend to copyrighted products in addition to patented ones.

Might help us in the future.

Cheers.