South Korea's gross domestic investment ratio has reached a five-year high thanks to expanding facility investment in the information technology sector including semiconductors.

According to Bank of Korea on Saturday, the ratio posted 31-point-five percent in the second quarter, the highest since Q2 of 2012.

The gross domestic investment ratio is an indicator of domestic firms' investment such as in facilities or construction at home. The figure shows an opposite trend from the overseas investment ratio.

In the April to June period, domestic facility investment grew 17-point-three percent year-on-year.

Investments in machinery such as those for manufacturing chips grew 26-point-seven percent on-year, which led the overall expansion in facility investment.

Investment in transport equipment edged down by half a percent from last year's second quarter but grew eight-point-seven percent compared to this year's first quarter with investment increases particularly in aircraft and autos.

For the entire first half of 2017, facility investment jumped 15-point-nine percent year-on-year.

With domestic facility investment posting gains, the overseas investment ratio recorded four-point-two percent in the second quarter, the lowest since two-point-nine percent in 2012.