In the past week, the VN-Index still anchored in the 1,900 point zone, but the next increasing sessions still repeated the index increasing model mainly thanks to a few large-cap stocks.
The strong impact of the Vingroup stock group is still an issue that many investors are interested in. In April, the increase of VN-Index mainly came from this group, when VIC and VHM contributed 129 points and 27 points respectively in the total increase of 179.6 points of the index. If excluding the Vingroup group, VN-Index is almost sideways, only increasing by 0.6%. In the early months of May, VIC and VHM continued to be the main drivers helping VN-Index surpass 1,900 points and set a new historical peak at 1,225 points.
The "mismatched" diễn biến of VN-Index in the past time has caused many investors to lose money even though the general index continuously went up. Many opinions worry that the market may enter the end of the upward wave or the distribution phase, when the index is mainly supported by some large-cap stocks, while the market breadth is not positive, short-term cash flow circulates and is not strong enough to spread.
In the opposite direction, there is also a view that the Vingroup group maintains the index momentum and stable psychology is still more positive than the scenario VIC, VHM decreased sharply. At that time, negative pressure may spread throughout the market, causing the loss level of many accounts to be deeper.
Financial analyst, Dr. Nguyen Duy Phuong - Director of Investment Analysis Division of DG Capital - said that the phenomenon of large-cap stocks strongly impacting the index is not only happening in Vietnam but is also common in many markets around the world.
According to him, if you closely observe the Vietnamese stock market in the past time, cash flow is not only concentrated in the Vingroup group but still appears in many separate industry groups. In April and early May, some bank stocks recorded significant increases, and the oil and gas group is also becoming the focus in the destination of cash flow.
This shows that cash flow has not withdrawn from the market but is rapidly circulating between industry groups with their own stories. Investors need to adapt to this movement characteristic, monitor the movement of cash flow according to each stock group instead of just looking at the general index," said Dr. Nguyen Duy Phuong.
Many experts believe that this is not a period to expect a strong breakthrough, but to test the durability of the historical peak that has been set.
VNDIRECT Securities Company offers the scenario with the highest probability for the market in May, which is VN-Index continuing to accumulate in the range of 1,820 - 1,910 points to create a foundation for a new upward trend in the third quarter of 2026. The market is said to need more consensus from foreign capital flows and more positive signals about inflation as well as liquidity of the banking system before forming a strong breakthrough.
In a more positive scenario, VNDIRECT said that VN-Index still has the potential to surpass the peak in May if the large-cap stock group continues to play a leading role. However, the "green shell red heart" phenomenon may recur when cash flow has not spread strongly to midcap and smallcap groups.
SSI Research experts especially note that May is usually a period of lack of supporting information. In that context, the significant increase in margin lending balance may be a factor to monitor. It is estimated that by the end of March 2026, margin balance reached about 424 trillion VND, an increase of 50% compared to the same period. Although the margin/equity ratio is still in control (about 102%), the margin ratio on free-float capitalization has increased to 13.4%, showing that the level of leverage is increasing.
SSI Research forecasts that profit growth may slow down in the coming quarters, due to the impact of high cost of capital, volatile fuel prices and high comparisons from the previous year. This may limit the market's room for increase and cause volatility to increase in the short term.
However, deep corrections, if they appear, may open up opportunities to accumulate stocks with attractive valuations for long-term investors. In the context of liquidity tending to decline in May, cash flow is likely to turn to mid-cap stocks with good fundamentals and clear profit prospects.
