Analysts believe the US Federal Reserve will slow the rate of its monthly asset purchases from the current $85 billion (£64bn) a month as members respond to signs of gathering momentum in the US economy.
The forecast cut of $10bn (£7.5bn) in quantitative easing (QE) on Wednesday will represent the first shift in the direction of policy since the Federal Reserve last raised interest rates in 2006.
The prospect of tapering has caused volatility in markets ever since Federal Reserve chairman Ben Bernanke suggested in May that asset purchases might be slowed later in the year.
However, it is likely that investors have now factored in the prospect of a shift in US monetary policy, although there is still a chance it may be delayed beyond this week's meeting.
The Syria crisis and the ongoing battle over extending the US debt ceiling have added to uncertainty over when the Federal Reserve will act on QE tapering.
The central bank has already said it will not raise interest rates until unemployment drops to 6.5%.
The jobless rate is now 7.3% but there are signs of economic improvement after the US grew at 2.5% in the second quarter.