US stocks nosedived on Thursday, with the Dow tumbling more than 1,300 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 as much as 5%. The S&P 500 ( ^GSPC ) dived roughly 4%, while the Dow Jones Industrial Average ( ^DJI ) tumbled more than 3.2%.

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 a 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 ( ^N225 ) 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.