South Korea’s state-run pension fund has sharply expanded its stock holdings in the country’s biggest four business groups for the past five years, with its sway over the conglomerates also growing, data showed Tuesday.

The National Pension Service, the country’s largest institutional investor, held 42.55 trillion won ($38.31 billion) worth of shares of the top 4 business groups ― Samsung, LG, SK and Hyundai Motor ― at the end of 2012, a huge increase from 11.46 trillion won at the end of 2007, according to the data compiled by its fund management division.

The top four groups accounted for 58 percent of the NPS’s combined stock investment at the end of last year, also a jump from 34.6 percent at the end of 2007, according to the data.

The combined market cap of the country’s top 10 business groups surged to 759 trillion won at the end of 2012, from 301 trillion won at the end of 2008 with their portion jumping to 60.1 percent from 48.3 percent over the cited period, separate data from the Korea Exchange showed.

The pension fund had its largest exposure of 22.06 trillion won to Samsung Group at the end of last year, accounting for 30.1 percent of the institutional investor’s total stock investment.

The NPS owned shares of Hyundai Motor Group affiliates valued at 10.9 trillion won at the end of last year. The comparable figures for LG and SK groups were 4.89 trillion won and 4.69 trillion won, respectively, the data showed. (Yonhap News)