Apple Inc.'s (AAPL) shock revenue warning sent ripples around world financial markets Wednesday as investors piled into safe haven assets such as the Japanese yen amid renewed concerns for the health of the global economy.

The yen, a traditional flight-to-safety assets in Asia trading owing to the size of Japan's U.S. dollar holdings and the depth and liquidity of its currency market, was marked 2.4% higher against the greenback at 106.43 in early Tokyo trade, after hitting a March 2018 low of 105.23, following the Apple warning. 

Early indications from U.S. equity futures prices suggest the Dow Jones Industrial Average will open around 310 points lower from Wednesday's close when markets resume trading Thursday, while those tied to the S&P 500 indicate a 32 point pullback. Nasdaq Composite futures are guiding to a 147 point slide for the tech-focused index. 

Apple Inc. (AAPL) shares fell sharply in after-hours trading Wednesday after the world's biggest tech company cut its current quarter revenue forecasts thanks in part to slowing sales in China.

In a letter to investors published after the close of trading, Apple CEO Tim Cook said revenue for the three months ending in December would come in around $84 billion, notably shy of the Street consensus of around $94 billion and the company's own previous guidance of between $89 billion and $93 billion.

"While we anticipated some challenges in key emerging markets, we did not foresee the magnitude of the economic deceleration, particularly in Greater China," Cook said. "In fact, most of our revenue shortfall to our guidance, and over 100 percent of our year-over-year worldwide revenue decline, occurred in Greater China across iPhone, Mac and iPad."

Cook also told CNBC television that the revenue slowdown was "100% from iPhone" and "primarily in greater China."

"It's clear that the (Chinese) economy began to slow there for the second half and what I believe to be the case is the trade tensions between the United States and China put additional pressure on their economy."

A key private reading of manufacturing activity in China, the Caixin-Markit PMI, slipped below the 50 level that separates growth from contraction for the first time in 19 months, according to data published Wednesday, as similar activity gauges around the region showed associated weakness over the month of December.

Apple shares fell more than 7.4% in after-hours trading following the release, and changed hands at $146.10, the lowest since July 12, 2017 and a move that extends the stock's three-month loss to around 35.5%.

Stocks in Apple's global supply chain were also notably weaker in early overnight trading, with Taiwan Semiconductor Holdings (TSM) falling 3.12%, Skyworks Solutions (SWKS) down 5.8% and Lumentum Holdings (LITE) down 8.2% 

Cook pinned the weaker iPhone demand in China on several factors, including a slowing economy worsened by "rising trade tensions with the United States." Cook also cited high prices tied to the strength of the U.S. dollar, fewer carrier subsidies and customers taking advantage of reduced battery replacements in the softened demand for new iPhones.