Seoul spent Wednesday doing something it has not managed much this month: closing quietly higher, without a scare in either direction. The KOSPI opened lower, drifted through a choppy morning as Wall Street's overnight chip selloff filtered through, and then found a floor as the wave of foreign selling that has defined the past week finally lost force. The index finished at 6,808.21, up 65.47 points (0.97%), back above the 6,800 line it lost on Monday.
The number that mattered was not the index. It was the flow. Foreign investors have sold Korean semiconductor shares aggressively for a week — more than 6 trillion won worth by local tallies, including nearly 4 trillion won of net selling in a single session on Tuesday. On Wednesday that selling all but stopped.
The short version: The KOSPI rose 0.97% to 6,808.21 as a week-long foreign selling wave abruptly thinned out and institutions stepped in. Samsung Electronics and SK hynix both closed higher on buyback flows, the won firmed to 1,384.8, and everyone is now waiting on two things: Nvidia's earnings and Thursday's Bank of Korea decision.
| Close | Change | |
|---|---|---|
| KOSPI | 6,808.21 | +0.97% |
| KOSDAQ | 826.87 | −0.03% |
| KRW/USD | 1,384.8 | won +1.3 won |
| Samsung Electronics | 261,500 won | +1.75% |
| SK hynix | 1,688,000 won | +0.60% |
Index and FX levels as of the 15:30 KST close; the won is quoted at the 15:30 fixing.
What moved the market
The session opened on the wrong foot despite a friendly overnight. New York had closed higher on Tuesday, 25 August — the S&P 500 up about 0.3% to 7,677.28, the Dow up a similar 0.3% to 53,579.94, the Nasdaq up roughly 0.6% — but Seoul still opened down 0.23% at 6,727.25. The drag was specific rather than general: memory-chip sentiment has been poor since Monday's US session, when Micron fell 5.8% and Broadcom 2.6%, and that was the move that triggered Tuesday's 4% intraday plunge in Seoul. Broad US strength does not help a market where roughly a third of index capitalisation sits in two memory companies.
What changed during the Korean session was supply and demand rather than news. Institutions were net buyers of about 760 billion won on the main board, according to Yonhap's tally, with local brokerages, private funds and pension money all adding. Foreign investors and retail investors were net sellers of a combined 2.36 trillion won — but the composition matters more than the total. Retail took profits into the rally once 6,800 was reclaimed. Foreign selling, which had been running in the trillions, shrank to a fraction of that by the close, with several local desks putting the day's foreign net sale in the low hundreds of billions of won.
Two corporate buyback programmes provided the other leg of support. SK hynix has been repurchasing roughly 650,000 of its own shares since last Thursday, and Samsung Electronics began buying this week following its record shareholder-return announcement. Buyback flows are mechanical, price-insensitive demand, and in a market where the marginal seller has been a foreign index fund, that matters.
Turnover was moderate: 323.3 million shares worth 22.38 trillion won (about $16.2 billion). Advancers beat decliners 584 to 273 — a broader session than the index move alone suggests.
The KOSDAQ did not join in, closing effectively flat at 826.87, down 0.28 points. Small-cap battery and component names lagged, and foreigners and institutions were both net sellers there.
Sector by sector
Semiconductors ended higher but without conviction. Samsung Electronics added 1.75% to 261,500 won; SK hynix rose 0.60% to 1,688,000 won. Both gains came late in the session. The caution is understandable — Nvidia's upcoming results are the single biggest scheduled event for the AI supply chain, and Korean memory is the most direct listed proxy for it outside Taiwan.
There is also an unresolved overhang under Samsung specifically. Short-selling in the stock ran at 8.81% of turnover on Monday, more than three times its annual average, after investors judged that a dividend-weighted shareholder return package fell short of the buyback-and-cancellation programme they had hoped for. That positioning has not cleared.
Nuclear power and electrical equipment were the day's standouts. Doosan Enerbility rose 4.46% to 84,300 won and HD Hyundai Electric closed near 690,000 won, both helped by reports that Washington has floated a joint Korean stake in Westinghouse Electric, the US nuclear firm now held by a Canadian private equity owner. Korea's power-equipment complex has been one of the year's more durable non-semiconductor themes, tied to global data-centre electricity demand.
Autos were the clear laggard. Kia fell 2.59% to 131,400 won and Hyundai Motor also closed lower. Batteries and materials were mixed rather than weak: LG Energy Solution finished unchanged at 349,500 won, POSCO Holdings slipped 1.20% to 328,000 won. Defence gave back a little, with Hanwha Aerospace down 1.36% to 1,087,000 won. Financials were quiet — KB Financial up 0.12%.
The won and the macro picture
The won strengthened modestly, closing at 1,384.8 per dollar, 1.3 won firmer than Tuesday. It opened stronger still, at 1,381.8, before settling into the mid-1,380s as the dollar traded soft and equity outflow pressure eased. The link is direct: foreign equity selling means dollars leaving, so a day when foreigners stop selling is usually a day when the won stops sliding.
The currency's recovery this year has been substantial. The Federation of Korean Industries put the second-quarter average at 1,501.9 won against an August average of 1,417.0 — a move large enough to change corporate planning assumptions, and it showed up in sentiment data. The FKI's September Business Survey Index came in at 102.0, above the neutral 100 line for the first time in six months. More notably, manufacturing (101.7) and non-manufacturing (102.4) were both above 100 simultaneously for the first time since October 2021. Pharmaceuticals, wood and furniture, textiles and retail all read strongly, though construction (97.6) and hospitality (92.3) stayed below the line — the recovery is not evenly distributed.
The immediate macro event is Thursday's Bank of Korea rate decision, and the market is genuinely split on it. The BOK raised its policy rate to 2.75% in July, its first increase in three and a half years. A Reuters poll of economists found a slim majority expecting a further move to 3.00%; a Korea Financial Investment Association survey of 100 bond-market professionals found 79 expecting a hold — a sharp reversal from last month, when 66% had forecast a hike. The arguments cut both ways: core inflation at 2.6% and second-quarter GDP growth of 0.6% quarter-on-quarter, three times the BOK's own forecast, argue for tightening; a firmer won, July's inflation slowdown and the equity market's recent volatility argue for waiting.
One structural risk worth flagging: margin loan balances have swollen by more than 5 trillion won this month to 32.63 trillion won. That is leverage sitting under a market that has moved 4% or more intraday twice in two weeks. It amplifies moves in both directions.
What to watch next
Nvidia's earnings are the near-term binary for Korean memory, and Seoul has spent the week positioning around them. Guidance on AI infrastructure spending will set the tone for Samsung and SK hynix more reliably than anything domestic.
The Bank of Korea decision on Thursday is a genuine coin-flip between 2.75% and 3.00%, and the accompanying language on household debt and the won will matter as much as the number.
Foreign flows are the thing to track through the rest of the week. One session of reduced selling is not a reversal. If foreigners turn net buyers of semiconductors, the 6,800 level looks like a base; if Tuesday's pace resumes, it does not.
Beyond that: the SK hynix union has rejected a share-heavy bonus package and returned to negotiation, SK Innovation's absorption of its separator unit SKIET takes effect on 1 January, and the Chuseok holiday demand cycle is beginning to show up in retail sentiment data.
Wednesday was not a resolution. It was a pause in the selling long enough for domestic buyers to reclaim a round number. Whether that holds depends on a US earnings call and a Korean rate vote, both of which land in the next twenty-four hours.
This is market information, not investment advice.
