May was the third month in a row in which more than 100,000 accounts were opened. There were 3.2 million retail accounts and nearly 12,000 belonging to organizations.

The invasion of the market by new investors took the total trading value on the Ho Chi Minh Stock Exchange (HoSE), Hanoi Stock Exchange, and Unlisted Public Companies Market to over VND531 trillion ($23 billion) in May.

HoSE accounted for VND448.5 trillion, a 19 percent increase from the previous month.

The boom has created pressure on the HoSE trading board, which had to shut down for the first time ever on Tuesday after the morning session as a surge in transactions threatened to overwhelm it.