The Supreme Court yesterday ruled unanimously against a small Oregon-based bus company that was seeking $5.2 million in damages from Greyhound Corp., the nation's biggest intercity bus line.

Concurring in the court's opinion, "with great reluctance, Chief Justice Warren Burger added that, "In my view, respondent is entitled to the award of treble damages ordered by the district court."

In his two-page concurring opinion, Burger restated the court's suggestion that the plaintiff, Mt. Hood Stages Inc. of Bend, Ore., has another legal route available to get the $5.2 million.

In January, the Supreme court let stand an award to Mt. Hood of $7.9 million in actual and punitive damages against Greyhound.

The earlier decision had no bearing on the one handed down yesterday, however.

At issue in the recent case was a provision of the Clayton Act that suspends the statute of limitations in a private suit when the government becomes involved.

Between 1947 and 1956, Greyhound acquired control of eight bus companies, virtually surrounding Mt. Hood's routes which run through Oregon, Idaho and Utah.

Mt. Hood opposed four of these acquisitions before the Interstate Commerce Commission, arguing that Greyhound could route traffic around the smaller line and deprive the public of the most convenient, direct service.

The ICC approved the acquisitions, nevertheless, after Greyhound made certain promises to the commission.

But the record shows that Greyhound quickly abandoned its promises, and the government filed suit against the company in 1964.

Mt. Hood argued that it should be able to collect damages back to 1960 under the four-year statue of limitations.

The 9th U.S. Circuit Court of Appeals agreed. It ruled that the statute of limitations had been suspended because the government intervened in a proceeding that Mt. Hood had initiated in 1964 before the ICC.

But Justice Harry Blackmun noted that under the Clayton Act, the United States must "institute" the action for the statute to be suspended. "In truth," said Blackmun, "the United States not only did not institute the proceedings, but was not in a position to do so."