The final composite is expected unrevised from the flash at 51.9 in the final report for December and down from 52.8 in November. The final services index is expected unrevised from the flash at 52.6 in the final report for December and down from 53.6 in November.

The Composite Purchasing Managers' Index (PMI) provides an estimate of private sector output for the preceding month by combining information obtained from surveys of the manufacturing and service sectors of the economy. Results are synthesised into a single index which can range between zero and 100. A reading above (below) 50 signals rising (falling) output versus the previous month and the closer to 100 (zero) the faster is output growing (contracting). The report also contains the final estimate of the services PMI. The data are provided by S&P Global using a representative sample of around 5,000 manufacturing and services companies, the former including Germany, France, Italy, Spain, the Netherlands, Austria, the Republic of Ireland and Greece and the latter Germany, France, Italy, Spain and the Republic of Ireland.

Investors need to keep their fingers on the pulse of the economy because it dictates how various types of investments will perform. By tracking economic data such as the purchasing managers' manufacturing indexes, investors will know what the economic backdrop is for the various markets. The stock market likes to see healthy economic growth because that translates to higher corporate profits. The bond market prefers less rapid growth and is extremely sensitive to whether the economy is growing too quickly and causing potential inflationary pressures.