A meeting between OPEC members Saudi Arabia and Venezuela with Russia and Mexico resulted in no deal to curb output against a 30 percent slump in prices since June, dragging Brent down before it rebounded on Wednesday as Saudi Arabia's oil minister said the oil market would stabilise.
Shares of PetroVietNam Gas, Vietnam's biggest firm by market value, fell 4.57 percent to end at 94,000 dong ($4.39), a level unseen since late May, and other energy shares also dropped, including Petrovietnam Drilling & Well Services Corp with a 3.49 percent decline.
Most Vietnamese equities fell slightly, while Saigon Securities Incorp, Vietnam's top brokerage by market share, bucked the trend to close up 0.68 percent with volume nearing a two-month high, Reuters data showed.
SSI shares may be sought by two major exchange-traded funds db x-trackers FTSE Vietnam and Market Vectors Vietnam during their restructuring in December, said analyst Uyen Nguyen of ACB Securities in a note to clients on Wednesday.