The KOSPI reversed an early dip to close at 6,808.21 (+0.97%) as Samsung Electronics (+1.75%) and SK Hynix (+0.60%) advanced on cheaper oil and lower US yields. The KOSDAQ ended flat, with Nvidia earnings, a Bank of Korea rate decision, and Jackson Hole all looming this week.
The KOSPI plunged as much as 4.3% on overnight US chip weakness before Samsung Electronics and SK Hynix powered an afternoon reversal, closing up 0.68% at 6,742.74. Foreign investors sold heavily into the dip while retail bought. Nvidia’s earnings loom Wednesday.
In Korea, a buyback lowers the share count for EPS purposes the moment the repurchased shares become treasury stock — but only cancellation makes that reduction permanent. Uncancelled shares can be resold or deployed for control, so the market prices a cancellation clause very differently from a bare repurchase pledge. Here is how to read the disclosures, the trust-contract loophole, and a checklist for judging any Korean buyback announcement.
Samsung Electronics’ record 110 trillion won shareholder-return plan fell short of market hopes, sending the stock down 8.7% and the KOSPI below 6,700. Rotation money lifted the KOSDAQ 1.4% as batteries and biotech rallied.
Seoul’s two markets went opposite ways: KOSPI recovered from a 1.35% opening drop to close up 0.88%, while KOSDAQ fell 4.63% and tripped its 32nd sidecar trading curb of 2026 as rising US yields hammered growth stocks.
A 2x daily-reset product does not double your holding-period return: after a +10% then -10% two-day swing, the underlying is down 1% but the 2x product is down 4%. Here is the reset mechanism, the decay math on volatile Korean names like Samsung Electronics and SK Hynix, and the FSC/KRX rules that govern these products.
The KOSPI jumped 5.89% to 6,852.58 after SK Hynix unveiled a record 40 trillion won buyback-and-cancellation plan. Foreign investors bought 1.7 trillion won of Seoul shares while the won hit its strongest level against the dollar in about 11 months.
Korea’s KOSPI closed down 5.80% at 6,471.17 after a US Treasury yield spike and a global semiconductor rout hit Samsung Electronics and SK Hynix. A sell-side sidecar fired at the open, retail investors bought the dip, and the won broke below 1,400.
The KOSPI surged past 7,200 intraday on a semiconductor rally, then an afternoon wave of profit-taking erased the entire gain, closing down 1.55% at 6,869.83. Foreign investors kept buying while locals sold, and the collapse of the US-Iran ceasefire added a fresh layer of risk.
The Bank of Korea Base Rate reaches Korean stocks through six channels: the won, foreign flows, valuations, bank margins, exporters, and retail leverage. As of August 2026, margin lending stood near 30.9 trillion won against 100.1 trillion won of investor deposits — here is how to read both around a rate decision.