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Markets & Semiconductors · Deep BriefSession of 28 Jul 2026

Asia-wide chip sell-off · one-page brief

Korea took the damage. Taiwan took the spillover.

On 28 July 2026 the TAIEX closed 2,030.83 points lower — the third-largest point drop in its history. Measured as a percentage it was the mildest fall of Asia's three big markets that day, and only the fourth-worst decline among the four largest point drops on record.

The Session in Four Numbers close · percentage · rank

  • 41,603.36TAIEX close, −2,030.83 pts
  • −4.65%Taiwan's decline — the mildest of the three
  • −11%KOSPI, into a circuit breaker
  • −13.5%SK Hynix, the epicentre

Where the Damage Landed Taiwan, by sector index

Sector indexMoveReading
Plastics 塑膠−8.30%Hardest hit — and unexplained by any chip narrative
TPEx 櫃買 (small/mid caps)−6.79%The AI supply-chain theme names, unwinding
Electronics 電子−5.11%Worse than the index; the weight that moved it
Semiconductors 半導體−4.42%In line with the index — not the epicentre
Financials 金融−1.92%Least affected of the majors
Telecoms 電信三雄+0.36 ~ +0.44%Two of the three closed higher — where the money went

What Follows 起 · 承 · 轉 · 合

BeatPageWhat it covers
摘要 Summary — this page1The session, the sectors, and why the headline number misleads
起 · 承 · 轉 Context & Pivot2What fell where · why memory · how to read a point drop
合 Resolution32026 in sequence · what would settle it · the open question

Bottom line

A crowded AI-memory trade unwound across Asia. The damage concentrated exactly where AI-demand assumptions were doing the most valuation work — memory names, small caps, MediaTek — and was absent where cash flow is present-tense: Taiwan's three telcos closed flat to higher. "Third-largest point drop in history" measures the index level, not the severity.

Source set: CNA (中央社), 28 Jul 2026. Context from AP-wire reprints, TradingKey, CNBC, Yahoo Finance, DigiTimes, TVBS, PChome/NowNews, SinoTrade, UDN. Percentages recomputed from points and closing levels, not copied.

起 — What Fell, and Where three markets, one trade

  • Epicentre · Korea

    KOSPI −11%

    6,012.68

    • Korea Exchange triggered a market-wide circuit breaker; trading halted 20 minutes.
    • Samsung Electronics −13.1%, SK Hynix −13.5%.
    • SK Hynix's US shares closed $143, below the $149 IPO price of its Wall Street debut earlier the same month.
    • This came after the index had already fallen roughly 30% over July.
  • Spillover · Taiwan & Japan

    TAIEX −4.65%

    41,603.36

    • Nikkei 225 −4.3% to 62,127.57; Hong Kong's Hang Seng actually closed up 0.41%.
    • Taiwan's electronics index −5.11%, semiconductors −4.42%, small-cap TPEx −6.79%.
    • Turnover NT$809.5bn; the close sat within ~38 points of the intraday low — no late bid.

承 — Why Memory, Specifically prose left · the split right

The trigger was not one event but a stack. Scepticism about the return on AI capital spending; Chinese competition, with ChangXin Memory Technologies named directly; and SK Hynix's own reported strategy shift through June–July — slowing its HBM4 ramp to redirect capacity into commodity DRAM, where shortage-driven margins had become more attractive. That last item is structural rather than a one-day event, and it is the one that re-rates the sector: it reframes memory makers from AI winners onto a commodity cycle. Overnight the Philadelphia Semiconductor Index had already fallen 2.2%.

  • 4 limit-downWinbond, Nanya, Macronix and PSMC all closed limit-down — the follower leg of a Korean move.
  • −2.98% vs −10%TSMC fell 2.98% to NT$2,280; MediaTek went limit-down. The closer to speculative AI content and further from committed foundry revenue, the harder the fall.
  • NT$809.5bnTurnover rose into the fall, and the index closed within ~38 points of the intraday low — capitulation volume, not a dip being bought.
  • +0.44% / +0.36%Taiwan Mobile and Chunghwa Telecom closed higher on stable cash flow and high yield — the rotation's destination, in the same session.

轉 — A Record Point Drop Is Not a Record Crash percentages recomputed from points and close

DatePointsCloseDecline (computed)As printed
2026/07/17−2,953.7143,304.74−6.39%−6.47%
2025/04/07−2,065.8719,232.35−9.70%−9.70%
2026/07/28−2,030.8341,603.36−4.65%−4.65%
2024/08/05−1,807.2119,830.88−8.35%−9.10%

Two rows of the published ranking do not reconcile with its own points and closing levels; the computed column is the one to trust. TAIEX has risen from five figures to the low 40,000s, so a 4.65% day now costs more points than a 9.70% day did fifteen months earlier.

合 — 2026, in Sequence the same index, five months

  1. 05-04TAIEX gains 1,778.51 points in one session — the largest single-day point gain on record — closing 40,705.
  2. 05-26All-time intraday high 44,097.63.
  3. 07-13A first memory wobble: global chip stocks slide as SK Hynix sells off after its Nasdaq debut, having roughly tripled over the year.
  4. 07-17Record crash: −2,953.71 points (−6.39%) to 43,304.74. Foreign investors sell a record NT$189bn in one day.
  5. 07-27Close of 43,634.19 — the record crash fully recovered, and 329 points above it.
  6. 07-28−2,030.83 to 41,603.36. More than five times that recovery given back in one session; ≈5.7% below the May high.
  • 44,097.63all-time intraday high, 26 May 2026
  • −5.7%Thursday's close below that high
  • NT$189bnrecord 1-day foreign net sell, 17 Jul
  • NT$500bnNational Stabilisation Fund capacity

If the Authorities Step In Taiwan's FSC toolkit

ToolMechanismSignal it sends
Short-sale curbsMargin requirement raised 90% → 130%First and lightest lever
Financing reliefCollateral broadened beyond cash to securities and tangible assetsAimed at forced-selling spirals
National Stabilisation FundUp to NT$500bn; last activated 8 Apr 2025 after the tariff crashRead as systemic, not a valuation correction

What Would Actually Settle It structure, not sentiment

  • Korean memory stabilising — the causal upstream. Taiwan's memory names are followers here, not leaders.
  • HBM4 versus commodity DRAM allocation. If SK Hynix is reallocating capacity into a shortage rather than responding to weaker HBM demand, this is a multiple re-rating, not a cycle turn.
  • Whether CXMT's progress is in shipped, qualified product or in announcements — that decides whether this is a 2026 earnings event or a 2028 structural one.
  • Earnings delivery from the small- and mid-cap AI supply chain, which Taishin Investment Advisory's Huang Wen-ching argues was priced for multi-year growth and stretched the index far from its moving averages (乖離).
  • Whether the July low holds. The 28 July close of 41,603.36 is the reference now — a second failure there would make the May-to-July advance the top of a range rather than a pause in a trend.
  • Regulatory response. Taiwan's FSC toolkit — short-sale margin from 90% to 130%, broadened financing collateral, and a National Stabilisation Fund of up to NT$500bn, last activated 8 Apr 2025 — would signal the authorities read this as systemic rather than as a valuation correction.

The unexplained figure

Taiwan's plastics index fell 8.30% — harder than semiconductors (−4.42%) and harder than the index itself. Nothing in the reporting explains why a traditional-industry sector led a session everyone agrees was about chips. Carried here as an open question rather than fitted to the story: it hints that indiscriminate deleveraging was also running.

Where it honestly lands

The direction is well corroborated: an AI-memory unwind, centred on Korea, spilling into Taiwan. The single clean cause is not established — sources emphasise different triggers, and anyone offering one is overclaiming.