Earnings of major South Korean companies are expected to improve this year, but discrepancies between industries are likely to widen, a local credit rating firm said on Monday.

The 'NICE Sales Index', which is calculated based on the 2026 sales estimates of 78 companies, came to 163.3 this year, up 5.6 percent from the previous year's figure, NICE Investors Service Co. said in its report, reports Yonhap news agency.

The NICE Industry Operating Profit Index, which uses earnings before interest and tax (EBIT) estimates for the companies, came to 10 percent, up 7.8 per cent from a year earlier.

The credit rating agency said robust growth of local chipmakers, power suppliers and electronics producers is expected to lead overall growth, amid the United States' effort to exclude China from taking part in its artificial intelligence supply chain.

But industries that are key to the U.S. economy, such as automobiles, could come under downward pressure, it added.

"Sectors, such as cars, could see their demand in the U.S. weaken and competition worsen, amid rising trade barriers and fading effects from pre-tax demands," the agency said in the report.

Meanwhile, South Korean stocks extended gains late on Monday morning on the back of a rally in semiconductor and other tech stocks.

The benchmark Korea Composite Stock Price Index (KOSPI) added 112 points, or 2.6 percent, to 4,421.63 as of 11:20 a.m.

The KOSPI opened higher to trade at over 4,400 for the first time despite a mixed close on Wall Street.

On Friday (U.S. time), the Dow Jones Industrial Average rose 0.66 percent to 48,382.39 points, while the tech-heavy Nasdaq Composite fell 0.03 per cent to 23,235.63.

Foreigners bought a net 872 billion won (US$602 million) worth of local stocks, offsetting institutions' and individuals' selling of 318.16 billion won and 550.9 billion won, respectively.