The Australian dollar has fallen moderately to 72.9 US cents, 56.7 British pence and 63.6 euro cents.
Meanwhile, bitcoin fell below $US5,000 for the first time in over a year, slumping to a fresh 13-month low — as a broad sell-off in cryptocurrencies that reignited last week gathered momentum.
The failed APEC meeting at Papua New Guinea over the weekend was the trigger for the volatile trading on Wall Street.
Apple’s stock, once again, tumbled over reports that its iPhone production is slowing down.
Also affecting sentiment was uncertainty over Brexit and British Prime Minister Theresa May’s political future, as members of her party attempt to bring on a no-confidence motion.
iPhone and Zuckerberg pressures
Apple’s stock tumbled 3.6 per cent and was, once again, the biggest drag on the broader market.
The technology giant has cut production orders in recent weeks for its three newest iPhone models (XR, XS and XS Max), according to the Wall Street Journal (WSJ).
The iPhone maker’s stock, which has played a major role in powering a decade-long bull run, is down more than 20 per cent from its record high in October.
It follows a disappointing holiday-quarter sales forecast and weak outlook from several of its suppliers.
Shares of Apple suppliers were also hit, including Lumentum Holdings, Universal Display Corp, Cirrus Logic and Skyworks Solutions.
The rest of the FANG stocks — Facebook (-5pc), Amazon (-3.8pc), Netflix (-4.5pc) and Alphabet (Google’s parent company) (-3.6pc) — also sustained heavy falls.
“Without the FANG leadership, including Apple, the market is going to struggle,” said Peter Cecchini, chief market strategist at Cantor Fitzgerald.
Facebook chief executive Mark Zuckerberg has reportedly adopted a more aggressive managerial style.
Mr Zuckerberg told 50 of his top executives earlier this year that Facebook was at war and is under pressure from lawmakers, investors and users, according to another WSJ report.
This report comes after backlash from a New York Times article detailing how Facebook ignored and then tried to hide that Russia used the platform to disrupt the US election in 2016.
US-China trade tensions rise
Tensions ramped up between the world’s largest economies at the APEC summit, with US Vice-President Mike Pence bluntly warning that America will not back down from further tariffs on China if needs be.
Asia-Pacific leaders meeting in Port Moresby failed to agree on a communique for the first time in the conference’s history, with US-China trade worries at the forefront.
Trade-sensitive stocks Boeing and Caterpillar fell 4.5 and 3.1 per cent, respectively.
The Dow Jones index dropped 396 points, or 1.6 per cent, to 25,017 at 8:15am (AEDT).
The benchmark S&P 500 also fell sharply, down 1.7 per cent to 2,691.
The tech-heavy Nasdaq was hardest hit, losing 3 per cent to 7,028.