Brexit fears couldn’t topple the bull market last year, nor could an escalating trade war with China, a presidential impeachment, and a potential military showdown with Iran that included attacks on the world’s largest oil facility and the U.S. embassy in Iraq. But in 2020, stock markets appear to have met their match in the new coronavirus, which last weekend escaped China’s best efforts at containment. “People have woken up to the risk,” said Tom Nun, a portfolio strategist with Great-West Investments in Greenwood Village.