The court ruled that victims of the worst oil spill in U.S. history may collect punitive damages from Exxon Mobil Corp., but not as much as a federal appeals court determined.
Justice David Souter wrote for the court that punitive damages may not exceed what the company already paid to compensate victims for economic losses, about $500 million compensation.
Souter said that a penalty should be "reasonably predictable" in its severity.
Exxon asked the high court to reject the punitive damages judgment, saying it already has spent $3.4 billion in response to the accident that fouled 1,200 miles of Alaska coastline.
A jury decided Exxon should pay $5 billion in punitive damages. A federal appeals court cut that verdict in half in 1994.
The Supreme Court divided on the decision, 5-3, with Justice Samuel Alito taking no part in the case because he owns Exxon stock.
Exxon has fought vigorously to reduce or erase the punitive damages verdict by a jury in Alaska four years ago for the accident that dumped 11 million gallons of oil into Prince William Sound. The environmental disaster led to the deaths of hundreds of thousands of seabirds and marine animals.
Nearly 33,000 Alaskans are in line to share in the award, about $15,000 a person. They would have collected $75,000 each under the $2.5 billion judgment.
In dissent, Justice John Paul Stevens supported the $2.5 billion figure for punitive damages, saying Congress has chosen not to impose restrictions in such circumstances.
Justice Ruth Bader Ginsburg also dissented, saying the court was engaging in "lawmaking" by concluding that punitive damages may not exceed what the company already paid to compensate victims for economic losses.
"The new law made by the court should have been left to Congress," wrote Ginsburg. Justice Stephen Breyer made a similar point, opposing a rigid 1 to 1 ratio of punitive damages to victim compensation.
