The Supreme Court's ruling upholding Obamacare'ssubsidies has positive credit implications forcarriers, Moody's said Thursday.

That's because it “removes uncertainty regarding individualpolicies sold in 2015 and serves to stabilize the individual healthinsurance market for future years,” the credit rating agencysaid.

Insurers that sold a significant number of policies on thefederal exchange—including Aetna, Humana, Anthem and United—aremost impacted by the decision, Moody's said.

In a statement, Humana applauded the ruling,saying it provides security for consumers nationwide who get theircoverage through an exchange-based plan.

“The Supreme Court ruling upholding subsidies means that peoplewho currently receive a subsidy—whether they're enrolled incoverage through a state-based or federal exchange—will continue toreceive the extra help,” Humana said.

The Supreme Court ruled 6-3 that the subsidies are legal on thefederal exchange, upholding a major tenet of Obamacare that enablesmillions of Americans to keep the tax subsidies that help them buyand afford health coverage under the law. A lot was at stake in thecase: An estimated 6.4 million consumers in 34 states currentlyreceive subsidies through the federal exchange to help them pay forhealth coverage.

“As a result of the Supreme Court decision, a great deal ofuncertainty regarding these polices has been avoided,” Moody'swrote in its analysis. “Had the Court found the subsidies to beillegal, a substantial number of these individuals would likelyhave canceled their polices either because they could no longerafford them or because they considered the polices not worthcontinuing at the full premium required.

“Since this latter group would most likely consist of healthierindividuals, not only would insurers' revenue and membership haveshrunk, but they would have been left insuring a less healthypopulation. Because insurance companies cannot change the premiumrates for the remaining portion of 2015, there would likely havebeen financial losses on these policies.”

Still, Moody's predicted, PPACA will continue to presentchallenges to carriers from provisions of the law that have not yetbeen implemented, including the Cadillac tax. Preliminaryrates showing premium increases also present a problem for2016.