South Korean shares closed lower on Tuesday because of heavy losses in technology stocks and higher bond yields. Shares of major market movers Samsung Electronics (KRX:005930) and SK Hynix (KRX:000660) fell over 1% and nearly 4% at market close.

Returning from a long holiday weekend, the Korea Composite Stock Price Index, or Kospi, decreased by 62.35 points, or about 0.9%, to close at 6,941.39. The Kosdaq rose by 26.63 points, or 3%, to close at 919.92.

U.S. Treasury yields climbed at the start of the week, with French and Spanish government bond yields also rising as investors weighed economic and political risks.

The 10‑year Treasury yield rose to 5.326% from 5.276% late Friday, while the 30‑year yield increased to 5.683% from 5.629%. The two‑year yield edged up to 4.841% from 4.823%. Both the 10‑year and 30‑year yields moved closer to multi-decade highs reached last week.

In economic news, the ASEAN+3 Macroeconomic Research Office (AMRO) expects South Korea's GDP to rise 3.3% in 2026, tripling from last year's growth of 1.1%.

The Singapore-based organization, however, expects the country's economic growth to cool down to 2.7% in 2027, according to its October update of the ASEAN+3 Regional Economic Outlook published Monday.

AMRO projects a similar trend with consumer prices. The organization expects South Korea's inflation rate to accelerate to 2.7% in 2026, then fall to 2.3% in 2027, still coming in slightly above 2025 levels.

In corporate news, Doosan Robotics (KRX:454910) was selected for two government-funded research and development projects focused on physical AI, with a combined budget of about 98.9 billion won, including 68.1 billion won in government funding, according to a Tuesday release.

One project will develop next-generation collaborative robots with on-device AI semiconductors for real-time perception, decision-making, and control. Commercialization of the robots as standard products is targeted from 2031, the release said.

The other project will develop AI-based robotic welding solutions with the help of vision systems, imitation learning, and digital twins for complex manufacturing processes, it said.

Shares of Doosan Robotics added over 2% at market close.