(WASHINGTON) -- With a Supreme Court decision imminent on President Obama's healthcare law, people around the world are gambling more than their health insurance on the court's ruling that could come Monday.
From New York to London, traders on the political stock market Intrade are buying stock to predict how the court will rule. And if the market is any indication, the future of the Affordable Care of Act, derisively called "Obamacare" by critics, doesn't look rosy.
According to the Ireland-based market, there is a 75-percent chance the court will rule the individual mandate, or requirement that every American buy health insurance, is unconstitutional.
Since the market pulls predictions from a large group consisting of political junkies, financial analysts and people who heavily research the topic, it is probably the "best predictor," said Koleman Strumpf, a professor of business economics at the University of Kansas School of Business.
Strumpf said, "Decisions by small groups of people in a closed room are hard to forecast" but "this is probably the best forecast."
Last March, before the Supreme Court began hearing the healthcare challenge, the market was considerably more optimistic that the individual mandate would survive.
On March 25, the day before oral arguments began, Intrade put the probability that the court would overturn the mandate at 35 percent. Within two days of the oral arguments, that probability shot above 60 percent.
Copyright 2012 ABC News Radio