US stocks nosedived on Thursday, with the Dow tumbling more than 1,000 points as President Trump's surprisingly steep "Liberation Day" tariffs sent shockwaves through markets worldwide. The tech-heavy Nasdaq Composite (^IXIC) led the sell-off, plummeting over 4%. The S&P 500 (^GSPC) dove 3.1%, while the Dow Jones Industrial Average (^DJI) tumbled roughly 3%. Among megacap techs, Apple (AAPL) shares fell over 8% amid concerns about disruption to its supply chain. China, the source of key iPhone components, was hit with additional US tariffs that raised its overall rate to 54%. Nvidia (NVDA) and other chip stocks also tumbled thanks to similar concerns. The two-step approach to tariffs unveiled by Trump on Wednesday imposes a baseline rate of 10% on all US trading partners but applies extra duties to countries considered "bad actors" on trade — meaning they face much higher rates. The levies go into effect on April 5 and April 9, respectively. In total, some 185 counties are impacted by the tariffs, and the new duties set the effective US tariff rate at its highest level in over 100 years. Read more: The latest on Trump's tariffs Stocks around the world sold off as the likelihood of retaliation from trading partners fueled fears of full-on trade war and a severe hit to global growth. The pan-European benchmark Stoxx 600 (^STOXX) sank over 2%, while Japan's Nikkei 225 slumped 2.7% to its lowest level since August. Meanwhile, Wall Street is digging into the fallout for US sectors and companies. Shares in retailers Walmart (WMT), Target (TGT), and Nike (NKE) fell, with risks to supply from Asian manufacturing hubs in focus. LIVE 18 updates