Taipei Stocks: TAIEX, TSMC and Foreign Flows — 2026-09-21
Taiwan stocks staged a V-shaped week: after closing below 46,000 on Sept. 14 on AI-slowdown jitters, the TAIEX roared back with a 892-point surge on Sept. 18 powered by heavy foreign buying, and extended gains Monday, Sept. 21, closing at 47,718.84 as TSMC rebounded to NT$2,480. Institutional flows flipped decisively positive mid-week, and TAIFEX announced temporary margin requirement increases.
Taipei Stocks: TAIEX, TSMC and Foreign Flows — 2026-09-21
Top developments
TAIEX surges 538 points to 47,718, TSMC back at NT$2,480
Taiwan stocks extended their rebound on Monday, Sept. 21, with the TAIEX up 538.09 points (+1.14%) to close at 47,718.84, lifting TSMC NT$20 to NT$2,480. The rally followed a 2.78% surge in the Philadelphia Semiconductor Index, which had pushed Taiwanese equities sharply higher in early trading.
Friday's explosive rally reclaims 47,000 with NT$1.07 trillion turnover
On Sept. 18 the TAIEX surged 892.75 points, closing at the day's high of 47,180.75, as a rebound in US technology and semiconductor shares sparked buying in TSMC, MediaTek and Delta Electronics. Turnover exploded to NT$1.07 trillion, and FTSE index rebalancing triggered a late-auction burst of 22,247 lots in TSMC.
Foreign investors return en masse after early-week sell-off
The week opened badly: on Sept. 14 the TAIEX fell 322.33 points to 45,862.52, closing below the monthly line, with foreign investors selling NT$36.96 billion — TSMC faced four straight sessions of foreign selling ahead of its dividend (除息), while UMC saw turned to buying. The tide reversed by Sept. 18, when the three institutional categories collectively bought NT$116.587 billion, with foreign buying near NT$87 billion and futures shorts reduced.
TSMC momentum builds ahead of Oct. 14 earnings
TSMC shares rose 1.44% to TWD 2,460 on Sept. 18 with volume of 37.19 million shares, and its NYSE ADR closed at USD 417.72 on Sept. 16 after Q2 2026 revenue rose 36.0% year over year to USD 40.2 billion. Investors are watching the Oct. 14 earnings date, with full-year growth guided slightly above 40%.
Local view
Local analyst commentary is cautioning that TSMC's weighting — estimated at around 44% of the index — has made the TAIEX "highly distorted" and unrepresentative of the broader market, noting that on Sept. 17 the weighted index rose 0.96% while the TPEX (OTC) index fell 0.26% (vocus.cc analyst salon). Wantrich/Wei-Jhen quotes veteran analyst Hsiao Ming-han warning that with US, Japanese and Korean indices all still below their monthly and quarterly moving averages, Taiwan's outperformance is unusual and "the most dangerous moment" may be at hand.
Context & numbers
- TAIEX close Sept. 21: 47,718.84 (+538.09, +1.14%); Sept. 18: 47,180.75 (+892.75); Sept. 14: 45,862.52 (−322.33)
- TSMC: NT$2,480 on Sept. 21; NT$2,460 on Sept. 18; unchanged at NT$2,380 on Sept. 17 in thin turnover ahead of the Fed decision (investors expecting a rate hike)
- Institutional flows Sept. 18: three institutions net buy NT$116.587bn; dealers net buy NT$22.998bn per Yahoo aggregation (data as of 2026/09/18)
On the radar
- TAIFEX announced a temporary increase in futures margin requirements on Sept. 18 — details worth monitoring for leveraged positioning
- TSMC Q3 2026 earnings scheduled for Oct. 14, 2026, with full-year revenue growth guidance slightly above 40%
- The index was within roughly 490 points of its all-time high intraday on Sept. 21 — a test of the record is a near-term catalyst
- Korea's August 1–20 exports jumped 78.3% YoY with semiconductor exports up 259.4%, flagged by local media as supportive evidence for Taiwan's AI/semiconductor supply-chain demand
This content was collected, curated, and summarized entirely by AI — including how and what to gather. It may contain inaccuracies. Crew does not guarantee the accuracy of any information presented here. Always verify facts on your own before acting on them. Crew assumes no legal liability for any consequences arising from reliance on this content.
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