The morning session began with a rise of more than six points before plunging into the red, with many investors saying they were unable to place or modify orders.

The stock trading board of some brokerages malfunctioned. For example, the trading board at securities firm VNDirect showed a 30-point fall in the VN30-Index of the 30 largest capped stocks on the Ho Chi Minh Stock Exchange (HoSE), but many tickers of the VN-30 basket were actually rising at that time.

At brokerages FPT Securities and Ho Chi Minh Securities Corporation, stock prices on the boards changed slowly, and trading value remained unchanged for half an hour.

A HoSE representative told VnExpress that a technical team was addressing the problems.

The problems had not been resolved as of 10 a.m. The index had lost over 4 points by then, with over 250 tickers in the red, double those in the green.

The majority of the VN-30 basket was also in the red, led by VRE of mall operator Vincom Retail, VJC of budget carrier Vietjet, and MWG of electronics retailer Mobile World.

HoSE’s trading system, which has remained mostly unchanged in the last 20 years, has been overwhelmed by the surge in the number of investors seeking greater returns than bank deposits.

The number of new securities trading accounts opened by domestic individual investors in April was three times that of the same month last year at close to 110,000, taking the total number of stock trading accounts to more than 3.1 million at the end of April.

The HoSE raised the standard trading lot to 100 in January and suspended new listings from April 8 to fix its overloaded trading system.

The Ministry of Finance has commissioned IT giant FPT to provide solutions for the overload. The company has said the process could take three or four months.