Low-income students are the ones most affected by the college debt crisis. Moreover, a new report has revealed that wealthy universities may be making it more difficult for this demographic to pursue higher education.

According to The Washington Post, the top 4 percent of colleges and universities have a third of all endowment wealth in higher education. Majority of those 138 schools, though, expect low-income families to shell out more than 60 percent of their income to cover the cost of attendance.

The data is from a report by the Education Trust which was released on Thursday. These wealthy educational institutions held at least half-a-billion dollars in endowment assets last 2013.

Deemed as the "$500 million club," these colleges benefit so much from their endowments because there is no required spending threshold and the funds are exempted from tax. With this, the Education Trust noted that these wealthy universities should enroll more low-income students and make education more affordable.

For their part, these universities argued that their endowments are unlike savings accounts from which funds can easily be drawn down. The institutions also said that they are raising money to cover the financial need of low-income students.

"We know that a lot of these institutions are doing great things for low-income kids, reducing the price that they pay," Andrew Nichols, a co-author of the report and the director of higher education research at Education Trust, said. "We're just asking them to do more because they have the capacity to do more. To whom much is given, much is required."

Nichols, along with co-author José Luis Santos, examined the spending rates of universities with a minimum of $500 million in endowment funds. They concluded that many of these schools could help low-income students by providing more scholarships with their funds.

"Every dollar spent today means there will be fewer dollars to spend in the future," University of Pennsylvania spokesperson Stephen J. MacCarthy added. "We are charged with finding an appropriate balance. Saying that spending today has no impact on the future is simply not true."