The feud erupted after Musk accused Trump’s recently signed tax-cut and defense spending bill of threatening the nation’s financial stability. Musk, once a key adviser to Trump during the early part of his second presidency, now plans to challenge Republican lawmakers who supported the legislation in next year’s midterms.

President Donald Trump blasted Elon Musk’s bid to start a new political party, intensifying a feud between former allies and deepening investors’ concerns about implications for Tesla Inc. and other companies led by the world’s richest man.

Investment firm Azoria Partners said on Saturday it will postpone the listing of its Azoria Tesla Convexity exchange traded fund after Tesla CEO Elon Musk said he was forming a new U.S. political party.