A federal jury on Wednesday said Philips Electronics NA should pay $466.8 million to Masimo Corp for having infringed two patents for technology used to help measure blood oxygen and track pulse rates.
Shares of Masimo closed 12.9 percent higher, rising $2.74 to $24.02 on the Nasdaq.
Jurors in Wilmington, Delaware needed less than a day of deliberations before ruling in favor of Irvine, California-based Masimo, following a two-week trial.
They also said Philips, a unit of Amsterdam-based Koninklijke Philips NV, did not show it more likely than not that Masimo had infringed one of its own patents.
"We are very disappointed in the verdict and will appeal," Philips spokesman Steve Klink said in an emailed statement. "We remain convinced that Philips has not infringed any valid, enforceable patent claims of the two asserted Masimo patents."
The case concerned technology for pulse oximetry, a non-invasive procedure to measure the level of oxygen saturation in a patient's blood.
Philips, which has offices in Andover, Massachusetts, had conceded having infringed Masimo's patents, but claimed the patents were void because they were "obvious" and described inadequately. The jury said Philips did not prove those claims.
Masimo had sued Philips in February 2009. A Masimo spokesman declined to comment on the verdict, and a lawyer for the company could not immediately be reached.
The case is Masimo Corp v. Philips Electronics NA et al, U.S. District Court, District of Delaware, No. 09-00080.
(Reporting by Jonathan Stempel in New York; Editing by James Dalgleish)