South Korean stocks hit a new high on Wednesday, surpassing the 5,300 mark for the first time as strong investor optimism around AI-related shares led to strong buying activity.

The Korea Composite Stock Price Index or Kospi rose by 83.02 points, or 1.6%, to finish at 5,371.1. The Kosdaq also increased by 5.1 points, or 0.5%, to end at 1,149.43.

In economic news, South Korea's foreign reserves marginally declined to $425.9 billion in January from $428.1 billion as of the end of December, the Bank of Korea said Wednesday.

The country's official forex reserves consisted of securities amounting to $377.5 billion, deposits of $23.3 billion, special drawing rights of $15.9 billion, gold worth $4.8 billion, and the country's IMF position at $4.4 billion.

South Korea's forex reserve holdings ranked the ninth largest globally as of the end of December, the central bank said.

In corporate news, HD-Hyundai Marine Engine (KRX:071970) secured a ship engine supply contract from Jiangsu New Yangzi Shipbuilding, according to a Wednesday filing with the Korea Exchange.

The contract, valued at 45.2 billion won, is valid until Aug. 5, 2029.

Shares of HD-Hyundai Marine Engine rose nearly 3% at market close.

In other news, LG Energy Solution (KRX:373220) secured a contract to supply a total of 5GWh energy storage system (ESS) project from Hanwha Solutions (KRX:009830) US subsidiary Hanwha Solutions Q CELLS, according to a Wednesday release.

The contract covers lithium iron phosphate (LFP) batteries for energy storage systems made at the Holland, Michigan plant, with deliveries planned from 2028 to 2030 for Hanwha Q CELLS' US grid-scale ESS projects, the release said.

The financial aspects of the deal were undisclosed.

Shares of LG Energy Solution rose nearly 3% at market close while those of Hanwha Solutions jumped 30%.