South Korea triggers 'sidecar' trading halt, KOSPI slumps over 7%

SEOUL, Oct 15 (Reuters) - South Korea's bourse operator triggered a sell-side "sidecar" trading halt early Thursday as the benchmark KOSPI index plunged more than 5%, tracking a tech-led selloff on Wall Street, where sticky US inflation data fuelled more rate-hike bets.

The automatic five-minute suspension on program sell orders was triggered after steep losses in index futures, an abrupt cooling mechanism, as the KOSPI .KS11 was set for its seventh straight session of losses, its longest losing streak since September 2024.

The benchmark KOSPI .KS11 was down 450.02 points, or 7.49%, at 5,558.79 as of 01:35 GMT. Chipmaker Samsung Electronics 005930.KS fell 9.05%, while peer SK Hynix 000660.KS lost 11.06%.

The market "is struggling to find a new buyer" after buybacks have run their course at Samsung and SK Hynix, said Mixo Das, head of Korea equity strategy at J.P.Morgan in Hong Kong.

"Over the next few weeks, we expect that process to evolve. And we think the most volatile part of this flow discovery is likely behind us. On a six- to 12-month basis, we still think that all of these AI stocks will be substantially higher than where they currently stand."

Among other index heavyweights, battery maker LG Energy Solution 373220.KS slid 3.44%, while Hyundai Motor 005380.KS and sister automaker Kia Corp 000270.KS were down 3.99% and down 2.03%, respectively.

Of the 889 issues traded, 90 shares advanced while 768 declined.

Foreigners were net sellers of shares worth 355.6 billion won.

The won was quoted at 1,339.5 per dollar on the onshore settlement platform , up 0.21% from its previous close at 1,342.3.

In money and debt markets, December futures on three-year Treasury bonds gained 0.12 point to 103.00.

The most liquid three-year Korean Treasury bond yield fell 3.0 basis points to 3.855%, while the benchmark 10-year yield fell by 2.1 bps to 4.224%.