The Supreme Court rejected a challenge to Obamacare’s health insurance subsidies in a 6-3 decision Thursday morning. The King v. Burwell decision will make a big difference to the 6.4 million Americans who were expected to lose their subsidies if the Court ruled the other way. And it’s making an even bigger difference to the health insurance industry, which relies on the subsidies to help poorer customers afford premiums.

The five largest publicly traded health insurance companies (UnitedHealth, Anthem,
Aetna, Humana and Cigna) — all of which were party to an amicus brief in support of the subsidies filed by America’s Health Insurance Plans, a trade group for insurance companies — rose an average of 1 percent over their opening prices by 11 a.m. Thursday. The bounce started at approximately 10:10 a.m., right when SCOTUSblog first announced the Supreme Court’s decision. All five companies.

That rise amounted to a $3 billion increase in the combined market capitalization of the five companies. And that figure underestimates the decision’s real benefit to these companies. According to FantasySCOTUS, a prediction market that has been fairly successful at forecasting the outcome of Supreme Court decisions, the government was favored to prevail in its case. Assuming investors were similarly optimistic about the government’s chances, the pre-decision stock prices likely reflected the predicted outcome, meaning the bounce started from higher up than it might have otherwise.