The Dow Jones fell almost 2.8 to 22,686.22 points just days after it completed its worst year in a decade.
A total of $75 billion was wiped off the value of the technology group, which was the biggest company in the world and the first trillion-dollar group until November.
He said many companies have a lot of sales in China and will "be watching their earnings downgraded next year until we get a deal with China". "Therefore, Apple's rare profit warning is a red flag for market watchers".
Macquarie Research analysts, however, have a more grim view of Apple's services business.
"I think there are a heck of a lot of US companies that have a lot of sales in China that are basically going to be watching their earnings be downgraded next year". Cook blamed "economic deceleration" in emerging markets and decreased demand for iPhones as drivers for the unanticipated shortfall - particularly pointing to the slowdown of China's economy in the latter half of 2018.
Apple's chief executive Tim Cook has his work cut out in China this year: the iPhone maker faces the looming threat of a court-ordered sales ban, the uncertain outcome of trade war talks and the roll-out of a new 5G network, where it finds itself behind rivals like Huawei and Samsung.
President Trump's latest interchange with reporters included new stock commentary, on news dominating the tech sector this week: He's not anxious about a drop in Apple's (AAPL +3.7%) stock price. Analysts had been forecasting US$91.3 billion, according to data compiled by Bloomberg. The US stock market in 2018 posted its worst year in a decade.
But over the past three months, the tech giant's stock price has been in a free fall - and the firm blames China's economy.
After Apple's first revenue warning in almost 12 years, investors also dumped chipmakers and tech stocks and flocked to perceived safe havens like U.S. Treasuries and the Japanese yen.
It looks like 2019 will be an ugly year for Apple.
Battered by negative Apple news, United States stock indices dropped sharply on Thursday morning. Microsoft shed 3.7 percent to $97.40. Makers of phone parts also fell. The S&P 500 technology companies had their worst day since August 2011. Boeing, which sells many of its planes in China, declined 4 percent to $310.90.
The tech company's troubles send a message for companies doing business in China, or suppliers with customers that do business in China, that the effects of trade tensions and a slowing economy are rippling to consumers, curbing demand and spending. They're supplying devices that compete on quality at much more affordable prices, and have set up huge local manufacturing operations to avoid tariffs and keep costs down.
Markets overseas also stumbled. "The fact that Apple didn't raise the issue of price in its pre-announcement letter maybe a reflection of the fact that there is no easy solution to the problem". Hong Kong's Hang Seng rallied 1.2 percent to 25,356.22.
Oil prices edged higher. Delta sank 7.6 percent. Both were large moves. Best Buy Co. fell 3.8 per cent while Target Corp. slid 1.2 per cent. Silver rose 0.9 percent to $15.80 an ounce.