Stock market today: Dow, S&P 500, Nasdaq futures sink after Trump targets allies with tariff threat over Greenland

US stock futures tumbled on Tuesday, signaling a rocky return to trading as President Trump escalated trade tensions with Europe over Greenland, reviving tariff fears just as earnings season picks up pace. Dow Jones Industrial Average futures (YM=F) pulled back 1.3%, pointing to a drop of over 600 points when markets reopen from Monday's holiday shutdown. S&P 500 futures (ES=F) fell 1.4%, while Nasdaq 100 futures (NQ=F) sank 1.7% on the heels of a losing week for Wall Street stocks. .Markets are grappli ...