(Bloomberg) -- Hospitals led a rally among health-care companiesas the U.S. Supreme Court upheld a key piece of President BarackObama’s Affordable Care Act, lifting the main threat hanging overthe industry’s prospects.

Read: Supreme Court upholdssubsidies

HCA Holdings Inc., Tenet Healthcare Corp. and Community HealthSystems Inc. all gained at least 8 percent after the ruling.

The court ruled 6-3 that tax subsidies can be providednationwide to help people afford health insurance. Obamacare hasprovided millions of paying customers for hospitals and healthinsurers, in part through the subsidies that were upheld today. Thenew clients have helped fuel a multiyear rally for health carestocks, and more consumers are expected to emerge in the comingyears.

“There are still a lot more people who haven’t gotteninsurance,” Steve Halper, an analyst at FBR & Co., said beforethe court’s ruling. “The states will expand their Medicaidprograms, and more people will comply with the mandate.”

Today’s ruling keeps subsidies flowing for about 6.4 millionpeople who are getting subsidies in the 34 states that rely on thefederal insurance exchange. It doesn’t affect those buying policiesin states like California and New York that run their ownmarketplaces.

Community Health rallied 9.6 percent to $60.53 at 10:20 a.m. inNew York. Tenet jumped 9.3 percent, while HCA, the largest U.S.for-profit hospital chain, gained 8.2 percent.

Stock gains at insurers were smaller, in part because subsidizedcustomers make up a small proportion of the total business at thebiggest firms. Still, the companies will benefit as more peoplepurchase coverage in the future. Health insurer stocks have alsorallied sharply in recent days amid speculation about mergers inthe industry.

UnitedHealth Group Inc., the biggest U.S. health insurer, gained1.9 percent to $121.41. Humana Inc. rose 2.6 percent and Aetna Inc.added less than 1 percent.

More than 10 million people have purchased insurance on thefederal and state marketplaces set up by the health-care overhaul,and about 85 percent have received government funds to help themafford the coverage, according to the Centers for Medicare &Medicaid Services. The Congressional Budget Office estimates thatmore than 20 million people will sign up for coverage on theinsurance exchanges in 2016.

For-profit hospital chains had about 2 percent to 5 percent oftheir earnings riding on the case, according to BloombergIntelligence.

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