September 2026 is a rather special time for the Vietnamese stock market when many supporting factors appear together, but the level of impact will not be uniform.
Interest rates are still one of the factors that have the greatest impact on the trend of the stock market. Meanwhile, the story of market upgrades will be a supporting factor and catalyst, especially for foreign capital and large-cap stock groups.
Investors expect the State Bank to maintain growth support policies, while encouraging banks to reduce lending interest rates for priority sectors. However, the room for easing is no longer too large because mobilization costs and liquidity pressure are still high.
This shows that lending interest rates may be reduced selectively, but it is difficult to form a strong interest rate reduction cycle on a large scale. Therefore, the diễn biến of exchange rates, interbank interest rates and liquidity regulation activities of the State Bank will directly affect the psychology as well as the scale of leverage use of investors.
In the context that the general level of interest rates is still relatively high and the possibility of interest rates remaining flat in September, the room for cash flow into the stock market to increase sharply may not be really clear.
However, if interest rates do not show further significant upward pressure, this is still a condition for investor sentiment to maintain stability. On that basis, investors expect the market to continue the positive trend and record a slight increase compared to August 2026, although the developments will be difficult to agree on a large scale.
The focus of September is the fact that the Vietnamese stock market enters a key upgrade phase from September 21, 2026. According to forecasts, foreign capital may disburse about 150 million USD in the initial phase. This is not only a supporting factor for cash flow, but can also improve investor sentiment and expectations for stocks that meet the criteria of foreign funds.
This factor may not be enough to determine the general trend of VN-Index, but it will contribute to promoting differentiation between stock groups. Cash flow is likely to focus on large-cap enterprises with high liquidity and well meeting the criteria of foreign institutional investors. Therefore, instead of a simultaneous increase, the market may witness a clearer circulation and selection of cash flow.
September may be a relatively "easy" period for short-term investors, but there is not enough basis to expect a "super wave". However, after nearly 10 months of adjustment, many stocks have discounted 20–30%, creating enough attractive space to attract new cash flow.
The positive scenario is that VN-Index has the opportunity to maintain a new uptrend in September, but this will be an uptrend accompanied by differentiation and strong fluctuations, instead of the entire market going up together. Matched order liquidity is only around 16,000 billion VND in some sessions, showing that cash flow has not really exploded. Therefore, the index may increase thanks to pillar stocks, while the rest circulates quickly according to each story.
Large-cap stocks still play an important role, in which VIC, VHM and VRE may continue to be "buffers" to help VN-Index maintain stability in the 1,800-1,950 point area. However, the focus of cash flow may gradually shift to leading stocks that have undergone a deep correction process and are having attractive valuations. Investors should not chase after strong gains but should take advantage of retests of the 1,800 point area to restructure their portfolios.
Opportunities in September may focus on leading stocks, groups directly benefiting from upgrades and the ability to attract foreign capital, as well as businesses associated with the story of restructuring and divestment of state capital.The market may therefore witness the process of reallocating cash flow from stocks that have increased sharply to businesses with low base prices and still room for revaluation.
