[Dongchun Weekly] May Week 5 — KOSPI Rockets 8% to Record While KOSDAQ Sinks 7%, Crypto Bleeds
Hey, Dongchun here.
Here is the Korean stock market weekly recap for the week ending May 31, 2026 — KOSPI, KOSDAQ, foreign investor flow, sector moves, and what is on deck for next week.
The only thing that mattered this week was the split: KOSPI rocketed roughly 8% to a record 8,476.15 while KOSDAQ collapsed about 7% in the same five sessions. The driver was a memory super-cycle and AI momentum lifting large caps only, fueled by a 19% monthly oil crash that pushed US 10-year yields down to 4.45%. Watch the May US jobs report on June 5 — it is the single variable that can reprice the entire rate-cut path heading into the June FOMC.
KOSPI and Korean Markets: The Week in Numbers
This week was decisively risk-on for equities but risk-off for crypto, and the single biggest driver was a 19% May oil collapse that fed disinflation into a memory and AI-led rally. It extended the S&P 500 to a ninth straight weekly gain.
US breadth was broader than it looked — Russell 2000 rose about 2% in line with the Nasdaq's 2.4%, so this was not a pure mega-cap squeeze. The participation of small caps alongside record highs argues for sustainability rather than a narrow blow-off.
Korea diverged violently from itself rather than from the US. KOSPI surged about 8% to a record on memory strength while KOSDAQ sank about 7% on biotech collapse, and EWY closed near $205.63 (up roughly 30% over 30 days), signaling strong foreign appetite for Korean large caps even as foreigners net sold on the cash market.
The macro variable that mattered most was the 10-year yield falling to 4.45% on the oil-driven disinflation read. Heading into next week, a hot May payroll print is the one thing that could reverse that yield relief.
Table 1 — Weekly index performance:
| Index | Week Open | Week Close | Weekly % | Note |
|---|---|---|---|---|
| S&P 500 | 7,473.47 | 7,580.06 | +1.43% | 9th straight weekly gain, record |
| Nasdaq | 26,343.97 | 26,972.62 | +2.39% | Record, +8% in May |
| Dow Jones | 50,579.70 | 50,668.97 | +0.18% | Fresh records, Thu close basis |
| Russell 2000 | 2,869.23 | 2,936.57 | +2.35% | Small caps participate, Thu basis |
| KOSPI | 7,847.71 | 8,476.15 | +8.01% | All-time high |
| KOSDAQ | 1,161.13 | 1,074.80 | -7.43% | Extreme divergence from KOSPI |
Table 2 — Macro Pulse:
| Indicator | Start of Week | End of Week | Weekly Change | Market Read |
|---|---|---|---|---|
| US 10Y Yield | 4.56% | 4.45% | -11bp | Oil-driven disinflation, equity-friendly |
| DXY | 99.24 | 98.99 | -0.25% | Soft dollar, supportive for KRW |
| VIX (weekly high) | 17.01 | ~15.7 | Calm | Stayed below 20 all week |
| EWY | n/a | 205.63 | Strong | +30% over 30 days, foreign appetite |
3 Korean Stock Market Themes This Week
Theme 1: Memory super-cycle reignites
On May 26 Micron surged 19.3% to become the first memory maker above a $1 trillion market cap after UBS tripled its target to $1,625 and confirmed HBM is sold out through 2026. SOX jumped 5.53%, its biggest single-session move of May. The catalyst transmitted almost directly into SK Hynix +9.31% and Samsung Electronics +2.68%, powering KOSPI's record run.
This theme carries into next week as memory pricing and HBM order data remain the key Korea transmission channel.
Theme 2: Oil collapses 19% in May
US-Iran ceasefire progress and Strait of Hormuz normalization hopes drove Brent down roughly 19% in May, its worst month since the Covid pandemic, with WTI near $88. The disinflation read pulled the US 10-year yield to 4.45%, supporting growth and semiconductor multiples.
Some peace headlines were later disputed late in the week, leaving the negotiation as a live variable into next week.
Theme 3: KOSPI record masks foreign selling
KOSPI printed records on May 27 (8,228.70) and again May 29 (+3.55% to 8,476.15), yet foreigners net sold heavily — minus 448 billion KRW on May 27 and minus 1.64 trillion KRW on May 28, concentrated in Samsung Electronics. Institutions and retail carried the index higher instead.
KOSDAQ fell three straight sessions on biotech collapse, so the large-cap/small-cap split is the structural variable to watch next week.
Weekend Catch-up: Korean Market News
Oil confirmed a roughly 20% drop from 2026 highs, with Brent ending May at $92.56. The US and Iran reportedly mostly agreed to a 60-day ceasefire memorandum, though analysts caution Hormuz reopening will be only partial. Monday's Korea open could see refining-margin and airline/shipping cost effects.
Crypto risk aversion deepened over the weekend. US spot bitcoin ETFs logged a record nine-day outflow streak of about $2.8 billion, the longest since launch. The Fear & Greed Index recovered to 33 (Fear) on May 30 after touching 22 (Extreme Fear) on May 28 — a clear split from equities' record run.
Space stocks tumbled on a May 29 Blue Origin rocket test failure. Satellite leader ASTS plunged 18.5% in a single session, retracing sharply from its all-time high. Korean satellite and aerospace names face negative sentiment at Monday's open.
Korean Sectors and Foreign Investor Flow
The strongest US sector this week was semiconductors, with Micron's $1 trillion milestone and a 5%+ weekly SOX gain leading the tape. AI software joined as Snowflake jumped 36.5% on May 28, its best day ever. This transmitted directly into SK Hynix (000660), which spiked 9.31% in a single session and anchored KOSPI's record.
The weakest US sector was energy as crude fell about 19% in May, dragging refiners and E&P names. In Korea, KOSDAQ biotech (Alteogen, Samchundang Pharm) collapsed and led the index down roughly 7% on the week.
Foreign investors were net sellers on KOSPI overall, concentrated in Samsung Electronics (005930), while institutions absorbed via SK Hynix and semis. The sector with the most follow-through potential into next week is memory/HBM, with ESS-battery as the secondary AI-derived theme after LG Energy Solution's +15.25% on the DTE deal.
| Sector | US Weekly | Direction | Korea Linked | Korea Weekly | Watch Stock |
|---|---|---|---|---|---|
| Semiconductors | SOX ~+5% | ▲ | Samsung (005930), SK Hynix (000660) | Strong | SK Hynix |
| Big Tech / AI | Nasdaq +2.4% | ▲ | NAVER (035420), Kakao (035720) | Mixed | NAVER |
| Energy | Oil -19% (May) | ▼ | S-Oil (010950), GS Holdings (078930) | Weak | Refiners |
| Financials | Flat | ◐ | KB (105560), Shinhan (055550) | Flat | Banks |
| EV / Battery | Mixed | ◐ | LG Energy (373220), Samsung SDI (006400) | Single-name spike | LG Energy Solution |
Kimchi Premium and Crypto in Korea
Bitcoin's weekly narrative was driven by ETF flows, not price alone. US spot bitcoin ETFs bled for nine straight sessions (~$2.8 billion), with roughly $1.42 billion of weekly fund outflows making it one of 2026's worst outflow weeks. BTC slid from about $78,000 to roughly $74,000, a weekly decline near 5%.
Ethereum and Solana underperformed alongside Bitcoin. ETH held the low $2,000s amid continued ETF outflows, while SOL fell about 6.78% to $81.37. BTC dominance climbed toward 60%, showing capital favored Bitcoin over alts in the risk-off move.
Kimchi Premium stayed compressed under roughly 1% recently, signaling soft local retail demand rather than the buying pressure seen in past rallies. Won-strength limits and regulatory friction kept the spread narrow.
Fear & Greed sat at 33 (Fear) on May 30 after a May 28 low of 22 (Extreme Fear), and total crypto market cap shrank to roughly $2.5 trillion. The one-line signal for next week: crypto risk-off is the clean counterpoint to equity records, and an end to ETF outflows is the first turn signal.
| Coin | Week Open | Week Close | Weekly % | Key Driver |
|---|---|---|---|---|
| BTC | ~$78,000 | ~$74,000 | ~-5% | Record 9-day ETF outflow ($2.8B) |
| ETH | ~$2,150 | ~$2,050 | ~-5% | Continued ETH ETF outflows |
| SOL | ~$87.3 | $81.37 | -6.78% | Risk-off, leverage unwind |
Kimchi Premium: under ~1% (compressed) as of late May 2026 Fear & Greed: 33 — Fear (May 30, weekly low 22 Extreme Fear)
This Week's KOSPI Prediction Scorecard
This week's directional calls on KOSPI mostly landed but consistently underestimated the magnitude — roughly 3 of 7 daily calls were clean hits, with the bullish bias correct but too timid. The repeated error was treating foreign flow as the index's swing factor when institutions and retail actually drove the record run.
The single best prediction was the Wednesday AM call for a gap-up toward new highs, which delivered an all-time closing high with SK Hynix +9.31%. The semiconductor transmission thesis from SOX worked almost exactly as written.
The biggest miss was Thursday PM's bearish setup calling for a gap-down and an 8,100 support test; instead KOSPI surged 3.55% to a record 8,476.15 on Friday. The lesson: in a memory-led tape, foreign selling did not cap the index because domestic buyers fully absorbed it.
| Day | Post | Key Prediction | Actual Result | Verdict |
|---|---|---|---|---|
| Tue | AM | Gap-up toward KOSPI 7,900, foreign buy signal | 8,047 +2.55%, foreigners +64.1B KRW | ✅ |
| Tue | PM | Flat/mild gap-up, foreign 2nd buy day | 8,228 +2.25%, 2nd buy day failed | △ |
| Wed | AM | Gap-up, semis volatility, test 7,900 | Record close 8,228, SK Hynix +9.31% | ✅ |
| Wed | PM | Nvidia earnings as single variable | Nvidia already reported May 20, misread | ❌ |
| Thu | AM | Flat open, cyclical rotation | -0.53%, foreigners -1.64T, no rotation | ❌ |
| Thu | PM | Mild gap-down, test 8,100 support | Friday +3.55% to record 8,476 | ❌ |
| Fri | AM | Gap-up, test 8,300 | 8,476.15 +3.55%, cleared 8,300 | ✅ |
Next Week's Korean Stock Market Playbook
The single most important variable next week is the May US jobs report on June 5. With PCE just printed at a near 3-year high of 3.8%, a hot payroll number could push the rate-cut timeline later and threaten the yield relief that powered this week's rally — it outweighs every other catalyst on the calendar.
US direction is Cautious-to-Neutral: nine straight weekly gains and record highs raise short-term overheating risk even with intact breadth. KOSPI is at all-time highs where foreign flow decides the next leg — a shift from net selling to buying opens a path to hold 8,500, while continued selling sets up an 8,300 support test as the bear condition.
The Monday open indicator to watch is foreign net flow in Samsung Electronics in the first 30 minutes — the cleanest leading tell for Korea's direction. The underappreciated risk is that KOSDAQ's 7% weekly collapse spreads into KOSPI mid-caps; the underappreciated opportunity is that an end to bitcoin ETF outflows could quickly flip crypto sentiment back to risk-on.
| Date | Event | Consensus / Expected | Market Impact |
|---|---|---|---|
| Jun 1 (Mon) | US ISM Manufacturing PMI (May) / Korea May trade data | Manufacturing check | Cyclicals, chip exports |
| Jun 3 (Wed) | US ADP, JOLTS, ISM Services PMI | Labor/services pulse | Rate-cut expectations |
| Jun 5 (Fri) | US May jobs report (NFP, unemployment) | Top variable of the week | Repricing the rate path |
| Jun 16-17 | FOMC (week after next) | Policy decision pending | Pre-positioning volatility |
A record-high index sitting next to a 7% small-cap wipeout and a crypto bleed is not a contradiction — it is a market that has decided AI cash flow is the only story worth paying up for, and everything else can wait.
So — what shape is next week taking?
That's the weekly wrap for 2026-05-31. Trade safe.
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