Businessman Donald Trump’s seemingly unstoppable presidential campaign might be losing its momentum. Texas Sen. Ted Cruz’s recent sweep in Colorado put up another speed bump in Trump’s path to the Republican nomination. While Trump claimed the Colorado outcome was “rigged” and “totally unfair,” his campaign is simply no longer winning all aspects of the race. Prediction markets are reacting to this latest hiccup for the Trump campaign. As the possibility of a contested convention in July looks more and more likely, Trump’s numbers have dipped. Prediction markets are where people bet on the possibilities of certain outcomes in politics, sports...