[Korea Market Close] KOSPI Rebounds to 6,835 as Hair-Loss Treatment Stocks Surge on Corporate Buybacks

The KOSPI closed at 6,835.80 on September 1, 2026, +0.23% from the prior close. The market absorbed overnight news of renewed U.S.-Iran military clashes, with the index dipping more than 1% intraday before recovering. The day's biggest gainer, however, came from an unexpected corner: a hair-loss treatment developer.

KOSPI daily chart, Naver Finance

The KOSPI opened at 6,784.29 and fell to a session low of 6,732.47 (−1.28%) before reversing course. It rose to an intraday high of 6,857.35 in the morning, then retreated in the afternoon before finding support again to close at 6,835.80—a 125-point intraday range.

Overnight, U.S. forces struck two rocket-launch sites on Larark Island in Iran. Iran retaliated against U.S. military bases in Jordan and the UAE. Geopolitical risk over the Strait of Hormuz resurfaced. Global crude jumped; U.S. and European equities fell on the session. Seoul's market opened to the downside in tandem.

All three investor categories sold. The index rose anyway.

Foreign investors sold 486.7 billion won. Institutional investors sold 633.9 billion won. Retail investors sold 539.8 billion won. All three main participant classes posted net outflows. Yet the KOSPI climbed. The difference: other entities—a classification capturing corporate insiders, self-dealing vehicles, and buyback programs—purchased 1,665.7 billion won, extending their buying streak to 10 consecutive trading days.

Samsung Electronics (+0.38%) and SK Hynix (+1.14%) both rose, anchoring the index. Both are actively repurchasing their own shares. When corporate buyback support arrives on a day all three external investor categories are selling, the index can hold. Today proved the pattern again.

Investor net flows by category:

Compiled and charted by author

Oil drove refiners higher. Rising rates boosted insurers.

Crude's surge flowed into refiner equities. SK Innovation surged 7.81%. SK Gas (+3.07%) and S-Oil (+1.07%) also advanced. SK Innovation's rally also captured momentum from a major ESS (energy storage system) win by affiliate SK On in the U.S. The SK group as a whole strengthened: SK Company (the holding company) rose 7.52%, and SK Square gained 2.89%.

SK Innovation 3-month daily chart, Naver Finance

Insurance stocks also moved sharply. DB Insurance +6.35%, Hanwha Insurance +5.71%, Hyundai Marine +4.91%, Mirae Asset Life +4.18%. The 3-year Korean government bond yield rose 4.0 basis points to 3.878%. The 10-year yield climbed 5.8 basis points to 4.371%. Higher rates boost insurers' investment income expectations. DB Insurance also unveiled a corporate value plan: it is raising its shareholder payout ratio from 35% to 50%.

By sector, retail trade (+2.98%), insurance (+2.15%), and finance (+1.52%) led. Construction fell 3.50%. Among large-cap decliners: Hanwha Aerospace −3.99%, LG Energy Solution −2.91%, Hyundai Mobis −2.21%.

KOSDAQ diverges. Hair-loss stocks hit the daily limit.

KOSDAQ told a different story. It closed at 821.25, −1.56%. Foreign investors sold for a third consecutive day; institutional investors sold for a fifth. Retail buyers alone could not offset the outflow. Semiconductor materials, parts, and equipment stocks were particularly weak. ISC −7.32%, Fadu −3.96%, Tes −4.91%. Battery stocks also retreated: Ecopro −4.49%, Ecopro BM −3.81%.

KOSDAQ daily chart, Naver Finance

Yet KOSDAQ's biggest mover hit the daily limit: JW Pharmaceutical surged 30.00%. Modern Pharmaceutical (+29.94%), Samick Pharmaceuticals (+26.72%), and Bionia (+25.14%) jumped in tandem—all hair-loss treatment developers. Bloomberg reported in late August that Wall Street investors are now watching for emerging hair-loss treatment companies following the GLP-1 (obesity treatment) investment wave. The U.S. hereditary hair-loss population is estimated at roughly 50 million men and 30 million women.

JW Pharmaceutical 3-month daily chart, Naver Finance

A day rocked by geopolitical headlines, yet the best-performing stock drew from an entirely different thesis. Macro and micro themes move independently, and today underlined the point.

Peptron, meanwhile, fell 9.66%—one of KOSDAQ's heaviest losses on the day.

Peptron 3-month daily chart, Naver Finance

Korea-North Korea cooperation stocks move separately.

Inter-Korean cooperation plays also rallied independently. Good People +22.39%, Codez Combine +12.54%, JS Tina +9.61%. U.S. President Trump is signaling readiness to re-engage with North Korean leader Kim Jong Un. Press reports indicate the White House is preparing for a possible summit. South Korea's National Intelligence Service has also signaled: in a closed-door parliamentary intelligence committee meeting, it assessed that "a North Korea-U.S. summit is possible at any time."

One geopolitical risk (U.S.-Iran tensions) shook the broad market. A different geopolitical possibility (North Korea talks) lifted specific thematic stocks. Two competing narratives with opposite momentum traded in the same market on the same day.

Today's key figures

Index	Close	Change
KOSPI	6,835.80	+0.23%
KOSDAQ	821.25	−1.56%
KRW/USD	1,370.4 won	+2.4 won
3-Year Gov't Bond Yield	3.878%	+4.0 bp

The pattern of the KOSPI holding ground via corporate buyback support was noted in yesterday's close summary. The pattern has repeated several times this week. JW Pharmaceutical's surge is part of a broader hair-loss treatment theme; more context is available in today's stock-in-focus article.

Watch two developments tomorrow: whether U.S.-Iran tensions escalate further and crude climbs; and whether other entities' buying streak continues. Ten consecutive days is substantial. How much longer this support can sustain the index will determine the near-term bias.

This article is a factual summary to aid investment research and does not constitute a recommendation to buy or sell any security. All investment decisions and outcomes are the reader's responsibility.

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