Shares tumbled on both national stock exchanges during September 3's session even when HSBC Vietnam announced the country's Purchasing Managers' Index (PMI) in August rallied to its highest level in four months.

On the Ho Chi Minh Stock Exchange, the VN-Index pared earlier gains to lose 0.11 percent, reaching 472.17 points.

Trading was sluggish, fetching only 86.7 percent of the previous session’s figure at 640.9 billion VND (30.2 million USD) and 29.2 million shares.

The VN30, tracking the 30 largest stocks, slid more than 0.6 percent to 527.92 points. Only three of the top 30 shares advanced, including PetroVietnam Low Pressure Gas Distribution (PGD) up 0.7 percent, Vinamilk (VNM) up 2.3 percent and Vinh Son-Song Hinh Hydro-power Co (VSH) up 1.5 percent.

On the Hanoi Stock Exchange, the HNX-Index finished the session at 60.65 points, 0.9 percent lower than the previous session on August 30. The value of trades plunged over 40 percent to just 81.98 billion VND (3.8 million USD) as 11.5 million shares changed hands.

The HNX30, representing the northern bourse's top 30 shares, also retreated 1.3 percent to 110.89 points. Foreign investors were net sellers in HCM City on the day by a margin of 29.13 billion VND (1.3 million USD) while they concluded as net buyers in Hanoi by a meagre value of 330.34 million VND (15,500 USD).-VNA