There are more than one definition of foreign investors (nhà đầu tư nước ngoài) under Vietnamese law:

• Foreign investors are defined under the Investment Law to mean … “foreign organization or individual using capital in order to carry out an investment activity in Vietnam”. The definition under the Investment Law seems to suggest that only companies incorporated outside Vietnam can be regarded as foreign investors.
• However, in subsequent decisions of the Prime Minister (Decision 88/2009 and Decision 55/2009), foreign investors also include enterprises established in Vietnam with more than 49% of capital contributed by “foreign parties” (bên nước ngoài). It is not clear if the term “foreign parties” are the same as “foreign investors” in the Prime Minister’s decision.
• The Ministry of Finance on the other hand consider foreign investors to include “enterprises established in Vietnam with 100% foreign contributed capital”.
• The latest document (Decree 102/2001) does not provide a definition of foreign investors but provides that companies incorporated in Vietnam of which foreign investors own more than 49% will be subject to the same investment and business conditions as those  applicable to foreign investors.

In summary, there are overlapping and confusing definitions of “foreign investors” under Vietnamese law. However, it is reasonable to conclude that such term will cover, among others, companies incorporated outside of Vietnam and companies incorporated in Vietnam of which foreign investors own more than 49%.