Vietnamese stocks tumbled on October 22 after the previous session's gains, following a further increase of 0.57 percent in Hanoi's consumer price index in October due to a major hike in food prices.

On the Ho Chi Minh City Stock Exchange, the VN-Index lost 0.2 percent to close at 500.57 points. The index has been fluctuating at around 500 points for four consecutive sessions, showing that pressure to sell remains high.

Bao Viet Securities Co analyst Nguyen Xuan Binh said in a note that the resistance of 503-505 points was a major challenge to the index. Speculative stocks had lost their attraction after a period of gains, he added.

"However, if the VN-Index can succeed at its resistance level, investors may want to hold on to shares for medium-term profit."

The VN30, composed of the city's 30 largest stocks in terms of capitalisation and liquidity, also shed 0.17 percent to close at 560.36 points.

Most blue chips retreated, and only Ho Chi Minh City Infrastructure Investment (CII), steelmaker Hia Pht (HPG), PetroVietnam General Services (PET), Refrigeration Electric Engineering (REE), Sacombank (STB), property giant Vingroup (VIC) and Vinh Son-Song Hinh Hydropower (VSH) posted gains.

Trading value declined by 33 percent compared to October 21, reaching 1 trillion VND (47.1 million USD) on a volume of around 75 million shares.

On the Hanoi Stock Exchange, the HNX-Index slid almost 0.5 percent to 61.66 points on a total turnover of 254.1 billion VND (5.5 million USD), dropping 31.7 percent over the previous session.

The HNX30, tracking the northern exchange's 30 big-hitters, also fell more than 0.8 percent to stand at 114.99 points.

Foreign investors continued to be net buyers on both bourses, with a combined margin of 23.2 billion VND (1.1 million USD).-VNA