The Korean stock market wrapped up the week's trading amid volatility. On the 21st, the last trading day of the week, the KOSPI and KOSDAQ moved in opposite directions, clearly highlighting the temperature gap between the two markets.

The KOSPI closed at 6,912.95, up 60.37 points (0.88%) from the previous trading day. In contrast, the KOSDAQ finished trading at 801.94, down a steep 38.95 points (4.63%). The difference in the two indexes' daily performance reached 5.51 percentage points.

◆ KOSPI Rebound Led by Samsung Electronics and SK Hynix

Judging by the early-session mood alone, the KOSPI was far from reassuring. The index opened lower at 6,759.95, starting the day below the 6,800 level, but then reversed course as large-cap semiconductor stocks such as Samsung Electronics and SK Hynix gained strength. It climbed as high as 6,954.12 intraday before entering the weekend having recovered the 6,900 level.

Looking at individual stocks, Samsung Electronics closed up 3.87% from the previous session at 281,500 won, while SK Hynix also rose 2.31% to 1.73 million won. Samsung Electronics preferred shares also surged 8.26%. The rally centered on large-cap semiconductor stocks helped fuel the KOSPI's rebound.

◆ KOSDAQ Triggers Sell-Side Sidecar... Top Market-Cap Stocks Weaken Across the Board

The mood on the KOSDAQ was different. The index fell more than 4%, retreating to just above the 800 level, and even triggered a sell-side sidecar during the session. Compared with the KOSPI, which recouped all of its early losses and turned upward, the gap in felt temperature was even starker.

In particular, the KOSDAQ's top market-cap stocks showed weakness in unison. Alteogen closed down 5.74% at 320,000 won, while EcoPro and EcoPro BM fell 7.26% and 7.45%, respectively. ABL Bio dropped 8.85%, and semiconductor equipment stocks such as Jusung Engineering and Wonik IPS could not escape the weakness either.

Ultimately, the market on the 21st produced conditions difficult to describe simply as 'KOSPI up, KOSDAQ down.' On the KOSPI, some large-cap, top market-cap stocks pulled the index higher, while on the KOSDAQ, selling pressure concentrated on major stocks in bio, secondary batteries, and semiconductor equipment, widening the index's decline.

◆ A Week of Alternating Sell-Side and Buy-Side Sidecars

Widening the view to this week, the volatility of the domestic market becomes clear. On the 19th, the KOSPI plunged more than 5%, triggering a sell-side sidecar. The very next day, the 20th, the mood reversed sharply as the KOSPI surpassed the 6,900 level intraday, triggering a buy-side sidecar, with the market's direction flipping in just one day. Then on the 21st, the KOSPI held the 6,900 level, but the KOSDAQ saw a sell-side sidecar triggered again. This week, sell-side and buy-side sidecars appeared in succession on the domestic market, underscoring how much market swings have widened.

Accordingly, in the new week, it will be necessary to watch not only the direction of the indexes but also whether differentiation among individual stocks within the market continues. In particular, whether the strength of the large-cap semiconductor stocks that underpinned the KOSPI will persist, and whether the KOSDAQ, pushed back to just above the 800 level, will succeed in rebounding, are cited as key points to watch.

◆ U.S. July PCE and Q2 GDP Preliminary Figures Scheduled for Release on the 26th

Overseas variables are also waiting in the wings. On the 26th, U.S. indicators related to July personal consumption expenditures (PCE) and preliminary second-quarter gross domestic product (GDP) figures are scheduled for release. As these are indicators that can gauge both prices and the economic trend simultaneously, the results could affect global financial markets' interest rate outlook and investment sentiment. Particularly given that daily swings in the domestic market have recently widened sharply, the movements of overseas stock markets and bond yields around the release of U.S. economic indicators are also noteworthy.

After a week in which sell-side and buy-side sidecars alternated, the KOSPI recovered the 6,900 level while the KOSDAQ stands at a point where its defense of the 800 level is being tested. Attention is focused on whether the two divergent markets will look in the same direction again in the new week, or whether the differentiated market trend will continue.