The index stayed in the red throughout the day and closed 20.55 points lower after gaining nearly 3 points Wednesday.
Most major Asian indexes, including the Nikkei 225 and Hang Seng Index, closed in the red after the Asian Development Bank said in a report that growth in developing Asia will likely be slower this year than previously thought as the war in Ukraine is expected to derail economic recovery in the region still reeling from the Covid-19 pandemic.
The VN30 basket, comprising the 30 largest capped stocks, saw 24 tickers in the red, led by VJC of budget airline Vietjet and VRE of retail real estate arm Vincom Retail, both with a 2.8 percent drop.
VJC is now lowest in a month, and VRE has hit a seven-day bottom.
PNJ of Phu Nhuan Jewelry lost 2.5 percent after reaching a new peak Wednesday.
MWG of electronics retail chain Mobile World closed 2.4 percent lower, while NVL of real estate developer Novaland Group dropped 2 percent.
Six blue chips gained, with POW of electricity producer Petrovietnam Power Corporation rising 1.5 percent and ACB of Asia Commercial Bank 1.2 percent.
Foreign investors were net sellers to the tune of VND526 billion, mainly selling VHM of real estate giant Vinhomes and HPG of steelmaker Hoa Phat Group.
The HNX-Index for stocks on the Hanoi Stock Exchange, home to mid and small caps, lost 1.17 percent, while the UPCoM-Index for the Unlisted Public Companies Market fell 0.88 percent.