Shares tumbled yesterday on the nation's two stock exchanges, halting several increasing sessions.

The reduction in petrol price by VND500 per litre prior to Monday's session was not sufficient for businesses to reduce their product prices, said Bao Viet Securities Co analyst Pham Tien Dung in a note.

"Especially when prices of raw materials such as kerosene and diesel, which account for a great proportion of price structure, remain unchanged, it will not make a big change to November's consumer price index," he said. Meanwhile, he predicted CPI this month would inch up 0.5 per cent.

"As the National Assembly meeting has not ended, the market will continue to lack policy information," he added.

The medium-term downtrend was unlikely to be reversed, Dung said, adding "some rallying will not be sustainable."

The VN-Index on the HCM City Stock Exchange went down 0.87 per cent to 385.22 points, although advancers outnumbered decliners.

Trading value fell by around VND200 billion (US$9.4 million) compared to Monday's level, ending at VND322 billion ($15.3 million) with 28.5 million shares changing hands.

Over two-thirds of the blue chips tracked by the VN30 retreated, while only two stocks added value – Kinh Do Confectionery (KDC) and Tu Liem Urban Development (NTL). The VN30 slid 1.19 per cent to 455.08 points.

The most influential stocks on the HCM City market suffered heavy losses. Vietinbank (CTG) dipped 3.7 per cent, while property developer Hoang Anh Gia Lai (HAG), Eximbank (EIB) and Vietcombank (VCB) also fell between 1.3-1.9 per cent.

On the Ha Noi Stock Exchange, the HNX-Index failed to retain yesterday's gains, declining 0.25 per cent to stand at 52.39 points.

As trading volume dropped to nearly 36.7 million shares, market value also decreased, totalling VND214.6 billion ($10.2 million).

At the close of yesterday's session, the HNX30 – representing the northern bourse's top shares – also shed 0.23 per cent to finish at 95.87 points.

Foreign investors still concluded yesterday as buyers on both stock exchanges by a margin of VND12.2 billion ($580,900).