It is impossible to define the typical investor in Vietnam because everyone can be one. There is in fact a multitude of diverse profiles but it is possible to classify them in three categories.
The first category is made of Vietnamese people who live abroad. They often have managed to get good jobs in countries where their parents (or themselves) immigrate years ago. They know their country well, they usually keep a string relationship with Vietnam and are fully aware of the potential of growth the country still has. They might not be finance experts or economists but they base their investment decision on what they see (growth in Vietnam is easy to notice when you look at the evolution of cars, construction of new buildings etc..) and feel about Vietnam.
The second category is made of non-Vietnamese investors who have Vietnamese family members (an husband, a wife, a brother in law..) or Vietnamese close friends.
Their investment are often inspired by their Vietnamese relation.
Finally, the third category of investors is made of investors who have no personal tie to the country but instead base their investment decision 100% on an analysis. These investors are willing to invest in Vietnam but can potentially invest in any other country. They are proper international investors and are often highly qualified with a strong understanding of finance and economic issues. They invest in Vietnam because they are fully aware of the potential returns they could earn. Their investments are most of the time long-term ones.