At another level, the breakup was a reminder of something else: the perils of personality-driven investing, a growing and lucrative business for the Wall Street bankers cranking out, rapid-fire, a never-ending array of new financial products.

Wall Street's stock indexes ended lower on Thursday in choppy trade as a slump in Tesla shares offset news of progress in tariff talks between U.S. President Donald Trump and Chinese leader Xi Jinping.

President Trump has been feuding with Elon Musk over The One, Big, Beautiful Bill. Here's why Musk could have suddenly changed his tune on the Trump administration.