The US S&P 500 has recorded its longest stretch of declines since the financial crisis in 2008.
That marks its eight day on the trot of drops - falling 0.4 per cent thanks to a drop in Facebook shares and ongoing uncertainty over the upcoming US presidential election, causing investors to dial back the risk.
The narrowing polls and falling oil prices have drowned out recent positive data signalling growth in the US economy, pushing the index down.
Elsewhere, the Nasdaq also fell for the eighth straight day, down 0.9 per cent to 5,058.41.
The Dow Jones finished 0.2 per cent lower at 17,930.67. All three started the day higher, but fell back later on.
While the S&P 500 has now fallen 2.9 per cent since 25 October, that's much less steep than the 23 per cent drop the index suffered in October 2008 for its last eight-session losing streak. That included the signing of the $700bn financial rescue package, weeks after the collapse of Lehman Brothers Holdings.
It's also not as bad as the Brexit slump, when the index fell 5.3 per cent over two sessions after the UK vote to leave the European Union in June. None of the eight sessions included a drop greater than one per cent, while Halloween's fall was less than a point in the index.
Some analysts have said the drop is more a sign of caution than fear, particularly after investors were given a shock in June, prompting a sharp sell-off.
But US shares are suffering as Hillary Clinton's lead in the US presidential election has been looking less assured in the polls.
On Wall Street, Facebook was down six per cent after it reported weaker than expected figures overnight and warned advertising growth would slow next year.
Fitbit was also out of puff - it was one of the heaviest fallers on Thursday, dropping 34 per cent - after a weak earnings forecast.
But not everyone was feeling blue: media giant 21st Century Fox bucked the trend with shares soaring seven per cent on the back of better than anticipated earnings.