Thomas said all donors were able to select how the money should be used.
"It may be on scholarships for students, special projects such as restoration of heritage buildings, or particular parts of Massey, such as the Wildbase wildlife hospital.
"In this case the donor asked that the gift be invested in a way that supports postgraduate scholarships."
Postgraduate qualifications include master's and doctorate degrees.
Thomas said it was particularly useful having the extra help for their postgraduate students.
"Postgraduate students often don't qualify for Government allowances and many then struggle with the demands of working to support themselves while studying.
"For them, the financial support of a scholarship allows them to reach their potential.
"[It] is sometimes the difference between being able to study or not."
The $3.4m lump sum is going straight to the foundation's endowment fund, currently worth about $30 million.
That means the donation will be useful for many years to come, as the money can be invested and only its profits will be spent.