Two U.S. appeals courts reached opposite conclusions on thelegality of a key financing provision of the Affordable Care Act,increasing the chance of another showdown at the Supreme Court overPresident Barack Obama's signature health-care law.

In majority ruling by judges appointed by Republican presidents,the U.S. Court of Appeals in Washington struck down an InternalRevenue Service rule providing tax subsidies to needy customers onthe insurance exchange run by federal authorities, saying Congressauthorized payments only on state- run marketplaces.

A panel of three judges in Richmond, Virginia, appointed byDemocratic presidents reached the opposite conclusion hours later,saying that while the language of the law is ambiguous, the IRS hadthe discretion to write rules for the Patient Protection andAffordable Care Act.