The Georgia Supreme Court on Monday ruled in favor of a Norcross company in a case that could lead to a $459 million judgment involving junk faxes.

The court ruled unanimously against American Home Services, which in 2002 and 2003 had sought to build its siding, window and gutter installation business. At the time, it hired a Texas company that sent out 306,000 unsolicited faxes of advertisements across the metro area.

Fastsigns, a Norcross firm that received one, filed a class-action lawsuit that accused American Home Services of violating federal consumer laws.

The state Supreme Court’s decision means American Home Services could be on the hook for a massive judgment. At issue was whether the company could be held liable for only the junk faxes that were received during the solicitation or, which the court ruled, the hundreds of thousands that were sent.

During arguments before the court in May, a lawyer for American Home Services said only six recipients of the company’s junk faxes had been identified. But a lawyer for Fastsigns said the Telephone Consumer Protection Act of 1991 was enacted to punish companies that clogged up people’s fax machines by sending unsolicited ads.

Justice Robert Benham, writing for the court, said the 1991 consumer law is clear: “A sender is liable for the unsolicited advertisements it attempts to send to fax machines, whether or not the transmission is completed or received by the targeted recipient.”

The court sent the case back to the Court of Appeals for consideration of other claims.

A Fulton County judge has already ruled that American Home Services violated the consumer protection law and issued a $459 million judgment — $1,500 for each of the 306,000 faxes it sent.

Michael Jablonski, a lawyer for Fastsigns, said the state Supreme Court’s ruling was not unexpected because other courts had issued similar opinions. “We will continue to fight on behalf of the thousands of people in the Atlanta area that received junk faxes,” he said.

Celeste McCollough, a lawyer for American Home Services, said there are other compelling reasons for overturning the $459 million judgment, saying the fact that only six targets of the faxes have been identified does not justify such a penalty. The company will pursue these issues in the appeals court, she said.