Fears that a massive programme of stimulus for the world's largest economy was about to be eased off have been thrown into confusion after disappointing US job figures were published.
The US has been nursed back to recovery from the financial crisis by the country's Federal Reserve pumping out billions of dollars every month in a form of asset purchases known as quantitative easing.
But fears that the improving health of the American economy would soon lead the Fed to begin tapering off the money flow have haunted markets over the summer and rippled out to provoke currency crises in emerging economies.
Expectations were high that this would be announced at a key meeting of the US central bank in less than two weeks.
New jobs figures from the US were seen as providing the last major economic data release before the event, at the end of a summer of speculation during which markets have been reacting feverishly to any apparent clues about its outcome.
However, the latest release only added more uncertainty. It showed the US added a below-expectation 169,000 jobs in August while revisions to July figures showed they improved by less than previously thought. Hiring has slowed since the start of 2013.
Meanwhile, the unemployment rate dropped to 7.3%, the lowest for five years, but this was as a result of the fact that more Americans stopped looking for work and no longer counted as unemployed.
It meant that the proportion of those working or looking for work was at its lowest level for 35 years.
The data set off a whirlwind of topsy-turvy market activity, with leading share indices on Wall Street and in the City climbing as fears over tapering seemed to fade.
But such is the anxiety over the Fed's thinking that reported comments by one policymaker that he might be persuaded to support starting to ease off stimulus sent stocks back down again.
The market movements ripple out to the real world beyond the US, with fears of tapering pushing up yields on Government bonds - rates which ultimately determine some borrowing costs for businesses and households.
Jitters over an end to stimulus have also provoked sharp movement in currencies such as the rupee, which has plunged recently as anxious investors start to pull out of emerging economies in favour of the greenback.
Analyst opinion was divided over what effect the latest data would have on the Fed's decision later this month.
Craig Erlam of Alpari said fluctuating interpretations of the figures sparked mayhem in the financial markets, adding that it would be "difficult to justify tapering" in the light of the disappointing data.
However Rob Carnell, of ING Bank, said the US labour market report on balance "did enough to keep a September taper in play".