The VN-Index rose by 0.31 per cent at 9.50am to 456.38 points, tracking the Dow Jones' steady performance.
The trading volume on the HCM City Stock Exchange was low as 29 million shares changed hands by 9.50am for a total value of VND738.4 billion (US$37.8 million).
About 110 stocks rose yesterday, while 76 declined in value. A number of blue chips stocks declined, including STB by 0.1 per cent, FPT by 3 per cent and DPM by 0.2 per cent.
Stocks with the highest gains were mostly small caps, such as DIC by 1.1 per cent, GTT by 0.5 per cent and PHT by 0.7 per cent.
In Ha Noi the HNX-Index rose by 1.33 per cent to close at 130.10 points.
About 29.3 million shares changed hands generating a turnover of VND662.1 billion ($33.9 million). Advancers outnumbered decliners by 102 to 82.
Phan Anh Tu, who heads the brokerage department at a HCM City-based securities' firm, said institutional investors who took advantage of the positive market sentiment were responsible for the rally on the country's bourses.
"The profit-taking before Viet Nam's national day is likely to begin today," Tu said. He said a strong performance by the Dow Jones last night and confidence among domestic investors would boost the country's stock exchanges.
Local media outlets report that Fitch Ratings downgraded the creditworthiness of Vietcombank and Asia Commercial Bank from D to D/E.
VCB fell 0.7 per cent and ACB rose 0.1 per cent.
To be updated