After briefly reversing the losses they suffered in early morning trading, US stocks dived back down again and experienced their biggest one-day fall in four years.
Read more: Black Monday: Equities bloodbath continues on US markets as Dow Jones and S&P 500 plummet
At close, Nasdaq was down 3.8 per cent at 4,526, while the Dow Jones Industrial Average and S&P 500 finished the day 3.6 per cent lower and 3.9 per cent lower, respectively.
According to Reuters, it's the biggest overall decline since 2011, and has pushed the S&P 500 and Nasdaq into correction territory.
The day has been volatile for US stocks – halfway through trading there were signs that US markets, unlike European markets, would end the day mostly unscathed by the panic surrounding China's economic slowdown.
The Shanghai Composite Index plummeted 8.5 per cent first thing on Monday, precipitating a global sell-off of stocks. In London, a total of £72bn had been wiped off the FTSE 100 by the end of trading, while €400bn (£294bn) was lost on the FTSEurofirst 300 index.
But the US exchanges seemed to regain investor confidence in the early afternoon,having plunged more than five per cent at the start of the day. Apple's stock climbed up to yesterday's closing value after tumbling 13 per cent in the morning, while Alibaba, GM and GE each went through a fall-and-rise of over 10 per cent.
But later in the afternoon they took a turn for the worse again, steadily declining until half an hour before the closing bell, when stocks shot up and then back down again in the space of 30 minutes.
A big plunge for US oil
Oil traded on the West Texas Intermediate fell to a new post-financial-crisis low this morning, trading at just $38.13 a barrel – a 5.7 per cent decline from yesterday.
Some improvement was made in early afternoon, but the value fell back down again towards the end of the day and closed 3.9 per cent lower.
Concerns have been growing that China is going through an economic slowdown, with fears exacerbated by last week's surprise devaluation of the yuan. This morning's fall on the Shanghai index was its biggest since February 2007.