HBCUs were founded to educate Black students at a time when Black students were generally barred from other institutions. The other two categories — historically Black colleges and universities and tribal colleges and universities — are designated as minority-serving institutions because of their historic mission to educate Black or Native American students. Predominantly Black Institutions (PBIs): Institutions where at least 40% of undergraduate students are Black Americans. Alaska Native and Native Hawaiian Serving Institutions (ANNHs): Institutions where a least 20% of undergraduate students are Alaska Native students or at least 10% of undergraduates are Native Hawaiian. Institutions where a least 20% of undergraduate students are Alaska Native students or at least 10% of undergraduates are Native Hawaiian.