US and European stock markets have lost ground again as global political and economic uncertainty continues to haunt investors.
Despite their apparent recovery on Wednesday, leading US indexes fell nearly 2% in early Thursday trading, following similar losses in Europe.
Weak US consumer confidence data for December sparked the latest sell-off.
However, analysts cautioned that volatile share price movements were exacerbated by thin holiday trading.
At one point, the Dow Jones index dropped by more than 500 points or 1.8%, while the S&P 500 fell by 48 points or 2%.
The tech-heavy Nasdaq also sunk by more than 2% or 135.4 points, with losses led by Tesla and Amazon.
On Thursday, the Conference Board reported that US consumer confidence fell sharply in December. The index declined to 128.1 from 136.4, a bigger drop than expected.
Earlier, European markets slumped in their first post-Christmas trading session.
London’s FTSE 100 slid as the day progressed, ending 1.5% down, with UK shares at their lowest in over two years.
Frankfurt’s Dax was 2.8% lower, while the Cac 40 in Paris suffered a smaller fall, down just 1.1%.
Concerns about US-China trade tensions also resurfaced, with reports saying US President Donald Trump is considering an executive order banning the use of Chinese technology.
The US, Australia, Japan and New Zealand have restricted use of ZTE and Huawei equipment in 5G mobile networks, and the UK is now considering doing the same.
On 20 December, the US indicted two Chinese men accused of hacking into computer networks of Western companies and government agencies, and accused Beijing of cyber-spying.
Theo Leggett, business correspondent
Wednesday’s spectacular rally on Wall Street may have provided some welcome relief for investors after weeks of falling share prices, but the euphoria was short-lived.
The factors which have been weighing on share prices since early December have not gone away.
Political uncertainty in Washington, trade tensions between the US and China, rising US interest rates and President Trump’s belligerent attitude towards policymakers at the US central Bank, the Federal Reserve, have all played their part, while in the UK, uncertainty over the Brexit process is also causing concern.
Volatility on the markets during a holiday period is not unusual, because fewer trades are being made than normal.
However, many analysts believe that in the current climate, investors are facing a turbulent ride well into the New Year.