ASEAN Stocks: VN-Index, JCI, SET, PSEi and KLCI — 2026-09-20

Top developments

Vietnam: FTSE Upgrade Triggers Foreign Inflows

On September 18, 2026, foreign investors in Vietnam recorded a net buy of approximately 1.2 trillion VND, marking a sharp reversal from previous selling trends ahead of the official FTSE Russell upgrade. The VN-Index surged intraday to 1,837.58 points before closing with mixed results due to ETF rebalancing pressures, but the weekly trend shows a 1.14% recovery driven by strong foreign accumulation. This "buy the news" phase is critical as Vietnam officially joins the FTSE Emerging Market universe on September 21, potentially attracting billions in passive fund flows.

Indonesia: JCI Slides on Heavy Foreign Selling

Indonesia’s Jakarta Composite Index (JCI/IHSG) closed at 6,441 for the week ending September 18, marking a 1.53% decline as foreign investors net sold Rp1.79 trillion over the period. On September 18 alone, foreign outflows reached Rp1.14 trillion, with major banking stocks like BBCA and BMRI facing heavy selling pressure. This divergence contrasts sharply with Vietnam’s inflows, highlighting differing regional risk appetites and specific domestic concerns regarding transparency and valuation.

Thailand: SET Volatility Driven by Tech Sector and Fed Watch

Thailand’s SET Index experienced significant volatility, closing at 1,584.15 on September 18, up 0.81 points, after earlier declines triggered by selling in technology stocks like DELTA and KCE. Investors are adopting a cautious stance ahead of the US Federal Reserve’s upcoming decisions, with foreign investors showing mixed flows but overall net selling in recent sessions. The market remains sensitive to global tech sentiment, with local brokers noting that the index is consolidating between support levels of 1,573 and 1,584 points.

Philippines: PSEi Stagnates Amid Growth Concerns

The Philippine Stock Exchange Index (PSEi) continues to struggle, with analysts pointing to a lack of clear inflection points despite attempts to "buy the dip." Economic growth projections for the Philippines have been downgraded to 3.4% for 2026, lagging behind regional peers like Vietnam and Malaysia. Recent data from early September showed net foreign selling of ₱342.25 million, reflecting continued caution among international investors regarding the country's macroeconomic outlook.

Local view

Vietnamese media, including Báo Dân Trí and VnEconomy, are heavily focusing on the "golden opportunity" presented by the FTSE upgrade, with headlines emphasizing the massive 1.2 trillion VND foreign net buy on September 18 as a signal of confidence. In Indonesia, CNBC Indonesia and Sindonews report growing anxiety over the JCI’s inability to hold gains, citing persistent foreign outflows from blue-chip banking stocks as a drag on sentiment. Thai outlets like InfoQuest highlight the market's sensitivity to external factors, particularly the US Fed, while noting that local retail investors are stepping in to support the SET index during foreign sell-offs.

Context & numbers

• Vietnam VN-Index: Closed near 1,837 points on Sept 18; foreign net buy ~1.2 trillion VND (Sept 18); weekly gain 1.14%.
• Indonesia JCI (IHSG): Closed 6,441 (weekly close); down 1.53% week-on-week; foreign net sell Rp1.79 trillion (weekly).
• Thailand SET: Closed 1,584.15 (Sept 18); turnover 71.4 billion baht; foreign flows mixed with net selling in tech stocks.
• Philippines PSEi: Recent data (early Sept) shows foreign net selling of ~₱342 million; index hovering around 6,069 levels.
• Malaysia KLCI: No fresh daily close data available in the last 7 days from provided sources.

On the radar

• September 21, 2026: Official effective date of Vietnam’s FTSE Russell Emerging Market upgrade. Watch for continued passive fund inflows and potential volatility as index trackers execute their rebalancing trades.
• US Federal Reserve Meeting: Global markets, especially Thailand’s SET and Indonesia’s JCI, are highly sensitive to upcoming Fed rate signals, which could influence foreign capital allocation across ASEAN.
• MSCI Review for Indonesia: While not immediate, ongoing scrutiny of Indonesia’s market transparency by MSCI remains a background risk that could impact long-term foreign investor confidence.