The immediate fallout from any sign of diminishing U.S. inflation would be further to boost expectations that the Fed will delay any slowing of its quantitative easing (QE) asset-buying program. Yellen has already fed this expectation at her confirmation hearing. Falling inflation would mean the QE money-printing might even be useful to ward off any deflation threat, on top of pumping up the economy. This, in turn, will provide some succor to emerging markets - particularly those with high current account deficits - that have seen their currencies clobbered as the prospect of U.S. stimulus ending has pulled cash out of their economies.
India, Indonesia and Turkey have been particularly hard hit this year.
Markit's flash PMI indexes are expected to underline the unevenness of economic recovery, particularly in the euro zone. Third-quarter gross domestic product released last week showed the euro zone barely growing with No. 2 economy France contracting and No. 1 Germany's pace of growth slowing. Analysts at Barclays described the euro zone as undergoing "a somewhat disappointing recovery".
The consensus forecast for the flash euro zone composite PMI, incorporating both manufacturing and services, is for a very slight rise to 52.0 from 51.9 a month earlier. That would indicate expansion and be the highest since the middle of 2011. But it is still below its long-term average. The U.S. economy is, on the face of it, in better shape. GDP grew at an annual 2.8 percent in the third quarter, albeit boosted by inventories.