The S&P Global South Korea manufacturing PMI shows a strong rebound in activity in May after two consecutive months of contraction in the sector, with the survey's headline index increasing to a two-year high of 51.6 from 49.4 in April. In addition to stronger current conditions, respondents also remain confident about the outlook.

Survey respondents reported the strongest increase in output in nearly three years, reflecting solid growth in both new orders and new export orders. Respondents have also reported an increase in payrolls after a previous decline and continue to expect output growth over the next twelve months. The survey shows a bigger increase in input costs but a slightly smaller increase in selling prices in May.

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.