The Dow Jones Industrial Average fell by around 500 points, or 2%, early in Tuesday trading, having dropped 400 points the day before.
A torrid session on Monday saw more than $130bn in market value wiped off the so-called FAANG stocks - Facebook, Amazon, Apple, Netflix and Google owner Alphabet.
That came after a report in the Wall Street Journal claimed Apple had cut production on all three of its iPhone models launched in September - adding to worries about its sales growth.
The sell-off marks the latest period of volatility for the New York market and Tuesday's trading saw the Dow fall back to its level at the start of 2018.
In London, the FTSE 100 was down by 1% on Tuesday while stock indices in France and Germany slid nearly 2%.