South Korean stocks opened lower Wednesday, as investors were cautious ahead of an upcoming speech by US Federal Reserve Chair Jerome Powell, which may offer clues on the future direction of interest rate hikes.

The benchmark Korea Composite Stock Price Index slid 11.68 points, or 0.48 percent, to 2,421.71 in the first 15 minutes of trading.

Powell is scheduled to speak on the economic outlook at a Brookings Institution session later this week, at which he will likely give a guideline on when the US central bank will start to scale back the size of the rate hike.

The Fed has raised the interest rate by 75 basis points four times in its aggressive monetary tightening aimed at reining in the decades-high inflation.

Analysts have largely priced in for the Fed's scale-down of the rate hike to 50 basis points in the next December policy meeting.

The S&P 500 and tech-rich Nasdaq on Wall Street closed lower Tuesday ahead of Powell's speech.

In Seoul, major stocks fell across the board. Market heavyweight Samsung Electronics fell 0.3 percent and leading battery maker LG Energy Solution dipped nearly 1.5 percent.

Platform giant Kakao was also down 1 percent and chemical producer Posco Chemical sank 3.6 percent.

Big banking firms gathered ground, with KB Financial rising 0.8 percent and Shinhan Financial gaining 0.5 percent.

The local currency was trading at 1,328.50 won against the US dollar as of 9:15 a.m., down 1.9 won from Tuesday's close. (Yonhap)