Apple Plunges $57 Billion in Premarket Trading, Dragging Global Stocks After Shock Sales Warning Global stocks slid after a shock revenue-guidance downgrade from Apple and troubling comments about the economic impact of the U.S.-China trade war from CEO Tim Cook.

After a roller-coaster day of trading to start 2019, global markets were enduring more turbulence Thursday after Apple warned investors that sales were slowing in China, reigniting fears about a slowdown in the world's second-largest economy.

"While we anticipated some challenges in key emerging markets, we did not foresee the magnitude of the economic deceleration, particularly in Greater China," Apple said after the close of trading on Wednesday.

Apple plunged 8% in after-hours trading and was down 7.7% in US premarket trading as of 1:10 p.m. in London (8:10 a.m. in New York). The rest of the so-called FAANG stocks (Facebook, Amazon, Netflix, and Google) followed Apple lower, and the slump in tech shares dragged down global markets.

Apple's shock revenue-guidance downgrade, along with troubling comments from CEO Tim Cook about the economic impact of the US-China trade war, added to fears that had already gripped investors.

"The trade tensions between the United States and China put additional pressure on their economy," Cook said in an interview with CNBC on Wednesday.

Cook's words, as well as continuing fears around monetary-policy tightening from global central banks and a general slowdown in the world economy, have helped push markets downward on the second day of trading in 2019.

Here's the scoreboard:

• FAANG stocks slid, with Facebook down 1%, Amazon down 1.1%, Netflix down 1.4%, and Google down 1.6% in premarket trading.
• U.S. stocks looked set for a substantial drop Thursday following Cook's comments, which came after markets closed on Wednesday. Futures pointed to a fall of 1.8% in the tech-heavy Nasdaq, while both the S&P 500 and the Dow Jones Industrial Average were set to open 1.1% lower.
• In Asia, China's Shenzhen Composite ended 0.8% lower, while Japan's Nikkei 225 lost 0.3%.
• As European trading kicked off, shares also fell, with the Euro Stoxx 50 broad index down 0.65% and Germany's DAX down 0.9%.

Thursday's market moves extend a brutal start to the new year after 2018 ended on a sour note for markets. The S&P 500 fell 6.2% in 2018, booking its worst year since the financial crisis and worst December since the Great Depression.