In the last month, several colleges and universities, including the University of Texas system and the Massachusetts Institute of Technology, have announced programs to provide free tuition for undergraduate students from families who fall below a certain income threshold.

Here are some of the schools that cover tuition for students from lower-income families and what’s behind these announcements.

Is tuition really free?

Each school administers its free tuition program in its own way, but the end result is that the cost of tuition is covered by grants and scholarships. These are not loans that students need to pay back.

Schools usually say that to qualify, a family’s income must be below a set amount and they must have assets typical for that income. So a family that makes under $60,000 a year but has millions in the bank may not qualify.

Some schools are also changing how they evaluate assets. The University of Pennsylvania said in November that it would no longer consider the value of the family’s primary home among its assets starting in the next academic year.

Where is free tuition being offered based on family income?

More than a hundred schools, including state schools and selective private universities, explicitly offer free tuition based on family income.