The index remained in the red throughout the day and started dipping to the 1,250 range in the early afternoon before falling non-stop in the last hour of trading to end with a 40-point drop.
This is the largest loss in a day since Feb. 8, bringing the index down to its lowest since April 2.
Trading value on the Ho Chi Minh Stock Exchange (HoSE), on which the index is based, fell nearly 11 percent to VND20.66 trillion ($). The bourse was dominated by red with 365 tickers losing and 80 gaining.
In the VN30 basket, comprising the 30 largest capped stocks, only two tickers, MWG of electronics retail chain Mobile World and VCB of state-owned lender Vietcombank, saw their prices unchanged, while the rest ended in the red.
Four tickers plunged by 6.9 percent, comprising MSN of conglomerate Masan Group, SBT of sugar producer Thanh Thanh Cong – Bien Hoa JSC, SSI of leading brokerage SSI Securities Corporation and VRE of retail real estate arm Vincom Retail.
SBT has experienced eight consecutive unchanging and losing sessions, falling by 13 percent in the last two weeks.
SSI dropped to its lowest this month, while VRE fell to March 26 levels.
Other major losers include CTG of state-owned lender VietinBank, down 6.8 percent, and STB of Ho Chi Minh City-based lender Sacombank.
VHM of real estate giant Vinhomes fell 5.1 percent, while VIC of its parent company private conglomerate Vingroup dropped 3 percent. The two tickers contributed most to the VN-Index plunge, pulling it down by a total 8.7 points.
Foreign investors were net sellers for the sixth session in a row to the tune of VND133 billion.
The HNX-Index for stocks on the Hanoi Stock Exchange, home to mid and small caps, fell 3.18 percent, while the UPCoM-Index for the Unlisted Public Companies Market fell 2.42 points.