South Korean shares closed sharply higher on Thursday, supported by strong gains by market-moving chipmakers Samsung Electronics (KRX:005930) and SK Hynix (KRX:000660), which added over 5% and 13%, respectively, at market close.

SK Hynix's solid jump in share price comes after it filed for a Nasdaq listing with the US Securities and Exchange Commission on Wednesday.

The benchmark Korea Composite Stock Price Index, or Kospi, rose 5.4%, or 459.28 points, to close at 8,930.3. The Kosdaq, however, declined by 2.4%, or 21.5 points, to end at 887.81.

In economic news, the composite business sentiment index in all industries in South Korea decreased 1.2 points to 97.7 in June from 98.9 in May, while the outlook for the next month fell by 2.4 points to 95.2, according to data released by the Bank of Korea on Thursday.

The seasonally adjusted composite business sentiment index for the manufacturing sector added 0.4 points to 101.2, while the outlook for the following month shed 2.1 points to 98.2, the central bank said.

For the non-manufacturing sector, the seasonally adjusted composite business sentiment index decreased 2.1 points to 95.4, while the outlook for the following month shed 2.7 points to 93.2.

Meanwhile, the economic sentiment index, a composite of the business survey and consumer survey indices, went down 0.7 points to 96.8.

In corporate news, SK Bioscience (KRX:302440) secured a supply contract of influenza vaccines from 2026 to 2027 from the Public Procurement Service of the Republic of Korea, according to a Thursday filing with the Korea Exchange.

The contract, valued at 23.9 billion won, is valid till June 30, 2027.

Shares of SK Bioscience jumped nearly 2% at market close.

In other news, Fitch Ratings assigned Korea Investment (KRX:071050) subsidiary Korea Investment & Securities a long-term credit rating of BBB with a stable outlook, according to a commentary released Wednesday.

The stable outlook reflects the rating agency's expectation that the brokerage, wealth management, proprietary trading, and investment banking services provider will maintain a balance sheet and financial profile in accordance with its current rating over the next one to two years.

Fitch Ratings will continue to monitor Korea Investment & Securities' evolving business model and risk profile, the release said.

Shares of Korea Investment Holdings rose nearly 5% at market close.