Because the models are wrong. They are based on faulty assumptions. Many investors (and economists) believe the efficient-market hypothesis. They are blind to how markets are often driven by politics. This is why emerging markets often rally when right-wing politicians win elections. It's not because fundamentals suddenly got better or because corporate earnings increased. It's because wealthy investors overwhelmingly prefer right-wing politicians, who they assume will serve their interests by promoting deregulation and privatization. We saw a ridiculous bubble emerge in Argentina's stock market immediately after the election of right-wing "libertarian" President Javier Milei, who has overseen an economic catastrophe. In Brazil, wealthy investors wanted Bolsonaro to win. In fact, they assumed he would win, and this was priced in. When he lost, they panic sold. It was driven by politics, not economic fundamentals.