Donald Trump announced Thursday the White House will scrap a key component of Obamacare legislation that helps low-income families to pay for healthcare—a move likely to destabilize insurance markets and send premiums soaring.

The administration will cut subsidies—worth about $7 billion in 2017—to insurance companies, with the White House proposing payments stop "immediately." Almost 6 million people qualified for the cost-saving payments this year, according to figures from the Department of Health and Human Services.