About 640 existing projects had their capital adjusted up by a total of nearly US$5 billion, up 2.3 percent year on year.
Capital contributions and share purchases by foreign investors fell 43.4 percent to US$2.81 billion.
Foreign investment was poured into 18 sectors, with processing and manufacturing absorbing the largest amount, with US$9.3 billion, or 48.4 percent of the total FDI inflow in the 8-month period.
Power generation and distribution followed with nearly US$5.5 billion, while real estate attracted US$1.6 billion and wholesale and retail sales US$734 million.
Of 92 countries and territories investing in Vietnam during the period, Singapore took the lead with more than US$6.2 billion, followed by Japan with more than US$3.2 billion and the Republic of Korea (RoK) with US$2.4 billion.
The Mekong Delta province of Long An led in attracting FDI with over US$3.6 billion, Ho Chi Minh City came second with about US$2.2 billion, and its neighbouring province of Binh Duong was third with US$1.7 billion.