A sudden sharp sell-off of blue chips on May 5 sent shares plunging on the HCM Stock Exchange, causing the VN-Index to close down by 1.5 percent to 479.29 points.

The value and volume of trades remained sluggish. Nearly 22 million shares changed hands during the session, generating a value of only 534.3 billion VND (25.1 million USD). Saigon Securities Inc (SSI) – the day's most-active share – was the sole stock to reach a volume of 1 million shares. SSI closed down 2.4 percent to 20,500 VND (0.98 USD) per share.

Six out of the 10 leading shares by capitalisation fell, with insurer Bao Viet Holdings (BVH) declining by 4.8 percent to 88,500 VND (4.23 USD) per share, while Masan Group (MSN) fell 4.7 percent to 123,000 VND (5.89 USD).

"The steep fall of BVH and MSN fueled broader profit-taking with other stocks, not only blue chips," said Hanoi-based broker Nguyen Quang Thuan, noting that while large-cap shares fell across-the-board by an average of 1.89 percent on May 5, penny stocks also declined by 1.24 percent and mid-caps by 0.8 percent.

Specific blue chips such as BVH or MSN had become almost the sole focus of the HCM City stock market in recent weeks, thanks to the strong accumulations by foreign investors, Thuan said. "Meanwhile, domestic capital hasn't improved due to economic concerns," he added.

Dang Anh, an analyst with financial website Stoxplus blamed looming electrical rate increases next month, quoting Deputy Minister of Industry and Trade Hoang Quoc Vuong as telling the newspaper Lao Dong (Labour) that rates might increase in June.

On the Hanoi market, the HNX-Index closed down 1.3 percent to 82.10 points, on a volume of 22.9 million shares. Kim Long Securities (KLS) topped trading on the northern market, with 1.6 million shares changing hands./.