South Korea's manufacturing PMI showed the sector expanded in September, with the survey's headline index increasing sharply to 50.7 from 48.3 in August. This is the first time the index has indicated expansion in the sector since the start of the year.

Survey respondents reported output, new orders and new export orders all rose in September after several months of declines, with respondents reporting improved demand from regional trading partners. Respondents also reported the biggest increase in payrolls in two years and continue to expect output to rise from current levels over the next twelve months. The survey shows a smaller increase in input costs but a bigger increase in selling prices.

The Purchasing Managers' Manufacturing Index (PMI) is based on monthly questionnaire surveys of selected companies which provide an advance indication of what is really happening in the private sector economy by tracking changes in variables such as output, new orders, stock levels, employment and prices across the manufacturing sectors.

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.

The Markit PMI manufacturing data give a detailed look at the manufacturing sector, how busy it is and where things are headed. Since the manufacturing sector is a major source of cyclical variability in the economy, this report has a big influence on the markets. And its sub-indexes provide a picture of orders, output, employment and prices.