Investors fear that the dispute between Elon Musk and President Donald Trump "will stop their friendship and change the regulatory environment for Tesla on the autonomous front over the coming years under the Trump administration,

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.

The relationship between Elon Musk and President Donald Trump appears to have entered a new phase of pronounced tension and public disagreement.