I. Overall US Stock Market Performance in September: Volatility Amid Record Highs, Clear Divergence in Tech Stocks

In September 2026, the US stock market exhibited a pattern of "upward volatility" influenced by multiple factors. As of September 20th, the Dow Jones Industrial Average (DJIA) closed at 38,950.12 points, up 1.2% from the end of August, setting a new record; the S&P 500 closed at 4,850.15 points, up 0.8%, also breaking records; and the NASDAQ closed at 15,320.78 points, slightly down 0.3%, due to adjustments in tech stock fluctuations. This divergent trend mainly stems from the "two extremes" within the tech sector: tech giants centered on AI (such as Nvidia and Microsoft) continued to strengthen, while chip stocks (like Intel and Micron) pulled back due to inventory pressure and slowing demand.

In terms of driving factors, the dovish signals from the Federal Reserve's September interest rate meeting were the core momentum for the market's rise. Fed Chair Powell stated in his September 18th press conference that inflation had significantly receded, and the Fed would "cautiously proceed" with interest rate cuts. Market expectations rose to 80% for a 25 basis point cut in November. This signal ignited market expectations for monetary easing, driving up large-cap stocks (such as DJIA components). Concurrently, the stronger-than-expected August services PMI in the US (55.2 vs. expected 54.5) indicated economic resilience, further supporting market sentiment.

II. Tech Stock Divergence: The Tug-of-War Between AI Frenzy and Chip Inventory Pressure

1. AI Sector: Second Wave of Gains Explodes, Leading Stocks Lead the Charge

In September, the AI sector was the brightest star in the US market. Nvidia (NVDA) stock reached a new high, closing at $780, up 5.2% from the end of August, driven by the company's release of the GPT-4.5 model, which boasted a 30% performance improvement, and sustained strong demand from data centers. Microsoft (MSFT) stock rose 3.8% to $410, with its Copilot business revenue increasing by 45% year-on-year, becoming the highlight of the earnings season. Amazon (AMZN) stock rose 2.1% to $180, with AWS cloud service revenue growing by 12%, of which AI-related services accounted for 35%.

Industry analysts point out that the second wave of AI gains stems from the deepening "application implementation." Previously, AI was mainly concentrated in model training and infrastructure; however, in September, enterprise AI applications (such as intelligent customer service and supply chain optimization) began large-scale commercialization, boosting demand for both software and hardware. For example, Salesforce (CRM) stock rose 4.5%, as its Einstein AI platform surpassed 100,000 customers, becoming a core tool for enterprise digital transformation.

2. Chip Stocks: Collective Pullback Due to Inventory Pressure and Slowing Demand

In sharp contrast to the AI sector, chip stocks faced headwinds. Intel (INTC) stock fell 3.2% to $45, as the company's earnings report showed an 8% year-on-year decline in PC chip demand and inventory turnover days rising to 120 days, above the industry average of 90 days. Micron (MU) stock fell 4.1% to $85, amid continuously falling DRAM memory prices and weak smartphone chip demand. TSMC (TSM) stock fell 2.8% to $120 because clients (such as Apple and Qualcomm) reduced orders, causing capacity utilization to drop to 85%.

The pullback in chip stocks is mainly due to two factors: inventory buildup and changes in demand structure. In 2025-2026, the chip industry experienced a "capacity expansion boom," but in 2026, the slowdown in consumer electronics demand (such as smartphones and PCs) was not fully offset by the growth in AI chip demand. Furthermore, escalating US-China trade friction led some chip companies to face supply chain risks, which further suppressed stock prices. III. Federal Reserve Policy Expectations: Interest Rate Cut Pace and Market Reaction The dovish signals from the Federal Reserve's September interest rate meeting were the core driver of the rise in US stocks in September. Powell stated at the press conference that inflation had decreased from 9.1% in 2022 to 2.8% in 2026, and core inflation (excluding food and energy) was stable around 2.5%, meeting the 2% target. He emphasized that future policy would be "adjusted based on data," but that they would "not rush to cut rates" to prevent inflationary rebound. The market's expectation of an interest rate cut gradually heated up. According to the CME FedWatch Tool, the probability of a 25 basis point cut in November rose from 60% at the end of August to 80% in September, and the probability of another 25 basis point cut in December rose to 70%. This expectation drove down Treasury yields, with the 10-year US Treasury yield falling from 4.2% at the end of August to 3.9% in September, which reduced corporate financing costs and supported stock market valuations. However, the Federal Reserve's cautious stance also brought some uncertainty. Powell mentioned that the labor market remained "tight," with unemployment remaining at 3.8% and wage growth at 4.2%, above the 2% target. If the labor market remains tight, it could lead to an inflationary rebound, thereby delaying the interest rate cutting process. This uncertainty caused a pullback in the Nasdaq in the latter half of September, as technology stocks are sensitive to interest rates. IV. New Trends in Vietnamese Capital Flows: Record High Inflow to US Stocks, Strengthening Cross-border Investment Logic In September 2026, the scale of Vietnamese capital flowing into US stocks reached a new high. According to data from the State Bank of Vietnam (SBV), Vietnamese investors channeled $1.2 billion into US stocks through cross-border investment channels (such as QFII and RQFII) in September, a 15% increase from August, setting a new high since 2023. The main reasons for this trend are: first, the global leading advantages of US stocks; second, the valuation attractiveness brought by the expectation of Fed rate cuts; and third, the need for asset allocation amid the volatility of the Vietnamese Dong exchange rate. In terms of asset allocation structure, Vietnamese investors tend to favor technology stocks and blue-chip stocks. According to a report from VNDirect, technology stocks accounted for 45% of US stocks held by Vietnamese investors in September, with Nvidia, Microsoft, and Apple (AAPL) making up 15%, 12%, and 10% respectively. Blue-chip stocks (such as S&P 500 constituents) accounted for 30%, as they have shown greater stability during the Fed's interest rate cutting cycle. The logic behind Vietnamese capital flowing into US stocks mainly has three points: first, risk diversification. The Vietnamese stock market is relatively small (total market capitalization of about 1.2 trillion USD), while the US stock market is the world's largest capital market, so allocating to US stocks can reduce single-market risk; second, capturing the growth dividends of global leaders, such as Nvidia's AI business and Microsoft's cloud services, whose revenue growth rates far exceed those of local Vietnamese companies; and third, currency arbitrage. The USD to VND exchange rate remained around 1:24,500 in September, appreciating from 1:25,000 in 2025, allowing Vietnamese investors to gain currency benefits by investing in US stocks.

V. Practical Strategies for Vietnamese Investors: How to Grasp Cross-border Investment Rhythms?

1. Asset Allocation: Balancing Tech Stocks and Blue Chips, Focusing on AI Dividends

For Vietnamese investors, the September strategy should be "balanced allocation, focusing on AI." On one hand, technology stocks (especially the AI sector) still have growth potential, but chip stock risks must be noted; on the other hand, blue-chip stocks (such as S&P 500 components) have shown stability during the Fed's interest rate cutting cycle and can serve as a "ballast."

Specifically, the suggested allocation ratio is: Technology stocks (AI + Software) at 40%, Blue-chip stocks (S&P 500 components) at 30%, Bonds (such as US Treasuries) at 20%, and Cash at 10%. Among these, technology stocks should select leading companies (such as Nvidia, Microsoft), avoiding the volatility of small and medium-cap tech stocks; blue-chip stocks should choose industries with stable cash flows (such as consumer goods or healthcare), like Coca-Cola (KO) or Johnson & Johnson (JNJ).

2. Currency Management: Hedging Exchange Rate Risks with Forward Contracts

The volatility of the Vietnamese Dong exchange rate is a major risk faced by Vietnamese investors. In September, the USD to VND exchange rate remained around 1:24,500, but Fed interest rate cuts may lead to USD depreciation, thereby affecting the returns of Vietnamese investors. It is recommended that Vietnamese investors use forward foreign exchange contracts (such as NDF) to lock in the exchange rate and avoid losses from currency fluctuations. For example, if an investor plans to sell US stocks in November, they can buy forward USD in advance to lock in the 1:24,500 rate.

3. Risk Control: Setting Stop-Losses and Avoiding Chasing Highs

Tech stocks are highly volatile, especially the AI sector, which is prone to "bubbles." Vietnamese investors are advised to set stop-loss points, such as selling when the stock price drops by 10%, to avoid deep losses. Furthermore, they should avoid chasing high prices and instead buy during pullbacks, such as buying Nvidia when the stock price pulls back to $700, rather than at the high of $780.

VI. Future Outlook: Interlinked Trends Between US Stocks and the Vietnamese Market

Looking ahead to the fourth quarter of 2026, the US stock market is expected to maintain a "volatile upward" pattern. On one hand, Fed interest rate cuts will drive up market valuations; on the other hand, the divergence among technology stocks will continue, with the AI sector remaining strong while chip stocks may continue to correct. The scale of Vietnamese capital flowing into US stocks is expected to grow further due to the increased demand from Vietnamese investors for global leaders, and the strong demand for asset allocation amid VND exchange rate fluctuations.

For Vietnamese investors, two key factors need attention: first, the pace of Fed interest rate cuts, and second, the performance of technology stocks. If the Fed cuts rates in November, market sentiment will further improve, and tech stocks may continue to rise; if tech stock performance is below expectations, a correction may occur. Moreover, the monetary policy of the State Bank of Vietnam (such as interest rate adjustments) will also affect capital flows from Vietnam, requiring close monitoring.