South Korea's top 100 large-cap companies have seen their surplus cash more than double over the past year as they are reluctant to invest amid the economy's prolonged sluggishness, data showed Wednesday.

According to the data by market tracker CEO Score, the leading companies had a combined surplus cash flow of 55.2 trillion won ($46.2 billion) as of the end of September, up 118 percent from a year earlier.

Cash flow refers to the cash that flows into and out of a company, while a surplus cash flow is the cash that exceeds the money required to cover its operating expenses.

The jump in their surplus cash flow was attributed to a combination of increased operating profit and a tumble in capital spending, despite near-stagnant sales growth.

In the first nine months of this year, the firms' combined sales inched up 1.4 percent on-year to 999.8 trillion won, but their operating income jumped 16.7 percent to 64.6 trillion won. In contrast, their capital expenditures plunged 21.4 percent to 67.3 trillion won.

Among the 100 large caps, chemicals and auto parts maker KCC Corp. posted the highest growth rate with its surplus cash flow skyrocketing 449 percent on-year to 141.5 billion won.

World's top smartphone maker Samsung Electronics Co. saw its surplus cash flow increase by the largest amount of 6.1 trillion won over the cited period, trailed by steel giant POSCO with 5.1 trillion won and leading automaker Hyundai Motor Co. with 4.8 trillion won.

As of end-September, Samsung Electronics had the largest surplus cash flow of 15.5 trillion won, with 14 companies holding 1 trillion won or more, according to the data. (Yonhap)