Vietnamese shares declined on Monday morning as large-cap companies began to suffer from profit-taking.
The benchmark VN-Index on the Hồ Chí Minh Stock Exchange fell 0.49 per cent to close at 988.48 points.
The benchmark index gained a total of 1.1 per cent last week.
More than 75 million shares were traded on the southern bourse, worth VNĐ1.72 trillion (US$74 million).
Large-cap stocks fell as they were hit by increased selling pressure.
The large-cap VN30-Index was down 0.73 per cent to end at 881.36 points.
Twenty-one of the 30 largest stocks by market capitalisation and trading liquidity in the VN30 basket declined while only six increased.
Among the decliners were steel producer Hòa Phát (HPG), property firm Vincom Retail (VRE), retailer Mobile World (MWG), Coteccons Construction (CTD), Sacombank (STB) and Vietinbank (CTG).
Investors are looking ahead to the Fed meeting and the US-China trade talks this week, the results of which will have a big impact on the movement of global markets.
On the Hà Nội Stock Exchange, the HNX-Index lost 1.10 per cent to end at 105.23 points.
The northern market index fell a total of 0.62 per cent last week.
Only 15 million shares were traded on the northern bourse, worth VNĐ187 billion.
The afternoon trading session starts at 1pm.