Serco has won a contract extension worth $900m (£671m) to assess whether people are eligible for affordable health insurance in the United States.
The support services company will continue work for the US Department of Health and Human Services, handling medical insurance purchases made through Federal Health Insurance Exchanges.
The exchanges were set up in 2010 through the Affordable Care Act, known as Obamacare, to allow people to compare insurance policies. Some people qualify for tax credits if they purchase their insurance through the exchanges.
Last year around 8.8 million Americans signed up for health coverage using the system.
Serco will be responsible for processing paper applications,...