President Donald Trump supports Medicare drug price negotiations, his spokesman said Tuesday, remarks that sent pharmaceutical stocks swinging again as investors tried to assess whether drugmakers will be forced into bidding wars for government business.

"He's for it, yes," White House spokesman Sean Spicer said at a press briefing in response to a question asking to clarify Trump's position on the matter.

Trump has given conflicting signals in the past weeks on whether he would let the government intervene directly in drug prices to reduce health-care costs. The Medicare program for the elderly is the biggest purchaser of health services in the country, and bidding for its business could have a major impact on Big Pharma's profits. Unlike most countries in the world, the U.S. doesn't directly regulate medicine prices, and drugmakers have strongly resisted it.