SAN FRANCISCO • After nearly five days of deliberations, a US jury has said Samsung Electronics should pay US$539 million (S$722 million) to Apple for copying patented smartphone features, according to court documents, bringing a yearslong feud between the technology companies into its final stages.

The world's top smartphone rivals have been in court over patents since 2011, when Apple filed a lawsuit alleging Samsung's smartphones and tablets "slavishly" copied its products.

Samsung was found liable in a 2012 trial, but a disagreement over the amount to be paid led to the current retrial over damages, where arguments ended on May 18.

Samsung previously paid Apple US$399 million to compensate it for infringement of some of the patents at issue in the case.

Because of that credit, if the verdict is upheld on appeal, Thursday's award will result in Samsung making an additional payment to Apple of nearly US$140 million.

In a statement, Apple said it was pleased that the members of the jury "agree that Samsung should pay for copying our products".

"We believe deeply in the value of design," Apple said.

"This case has always been about more than money."

Samsung did not immediately say whether it planned to appeal against the verdict but said it was retaining "all options" to contest it.

"Today's decision flies in the face of a unanimous Supreme Court ruling in favour of Samsung on the scope of design patent damages," Samsung said in a statement.

"We will consider all options to obtain an outcome that does not hinder creativity and fair competition for all companies and consumers."

The new jury verdict followed a trial in San Jose, California, before Judge Lucy Koh that focused on how much Samsung should pay for infringing Apple patents covering aspects of the iPhone's design.

The jury awarded Apple US$533.3 million for Samsung's violation of so-called design patents and US$5.3 million for the violation of so-called utility patents.

Apple this year told jurors it was entitled to US$1 billion in profits Samsung made from selling infringing phones, saying the iPhone's design was crucial to their success.

Samsung sought to limit damages to about US$28 million, saying it should pay only for profits attributable to the components of its phones that infringed Apple patents.

Jurors in the earlier trial awarded US$1.05 billion to Apple, which was later reduced.

Samsung paid US$548 million to Apple in December 2015, including US$399 million for infringement of some of the patents at issue in this week's trial.

Apple's case against Samsung raised the question of whether the total profits from a product that infringes a design patent should be awarded if the patent applies only to a component of the product, said Ms Sarah Burstein, a professor of patent law at the University of Oklahoma.

The verdict appears to be a compromise between Apple and Samsung's positions, and does not offer much clarity on that question, said Ms Burstein, who predicted Samsung would appeal to the US Court of Appeals for the Federal Circuit.

"This decision just means we are going to have more uncertainty," Ms Burstein said.

"Smart tech industry players are waiting to see what the Federal Circuit does. This is just one jury applying one test."

REUTERS