Korean shares opened lower Thursday, after the previous session's sharp gains as investors weighed concerns over the profitability of artificial intelligence (AI) infrastructure investments. The benchmark Korea Composite Stock Price Index (KOSPI) fell 65.55 points, or 1.14 percent, to 5,670.11 at the opening bell, after jumping 3.29 percent in the previous session. Overnight, U.S. stocks closed mixed as AI-related shares rebounded following SpaceX's quarterly results. The Dow Jones Industrial Average rose 0.69 percent, while the S&P 500 gained 0.58 percent and the tech-heavy Nasdaq Composite advanced 1.05 percent. After delivering sound earnings, Meta Platforms boosted its bet on the AI sector.