Shares tumbled on the Vietnamese stock market on September 9.

After successfully posting gains last week, the VN-Index on the HCM City Stock Exchange went down more than 2 percent to close at 470.16 points.

Such a decrease is often caused by negative rumours or potentially harmful policies. However, as of late September 9 afternoon, there was no such information.

Domestic media reported that the investigation agency under the Ministry of Public Security arrested the chief of the Vietnam Development Bank's Soc Trang branch and director of LienVietPostBank's Hau Giang branch on September 7. But these bank branches are small and the arrests will not significantly impact the market.

The VN30, tracking the bourse's top 30 shares, also retreated 2 percent to close at 524.17 points.

All 30 stocks posted slumps. Becamex Infrastructure Development (IJC) plunged to the floor price, while many other blue chips declined more than 3 percent, including insurer Bao Viet Holdings (BVH), Vietcombank (VCB), steel firm Hoa Sen Group (HSG) and logistics company Gemadept (GMD).

Trading value dropped 36.8 percent from September 6, reaching 802.8 billion VND (37.8 million USD) on a volume of 54.9 million shares.

On the Hanoi Stock Exchange, the benchmark HNX-Index fell 1.3 percent to 59.67 points.

The value and volume of trades decreased slightly over the previous session, totalling 126.9 billion VND (5.9 million USD) and 19.15 million shares.

Foreign investors remained net buyers on both bourses, but the value significantly dropped to 11.35 billion VND (535,300 USD).-VNA