More than 1,600 alumni of Harvard University say that they will withhold donations to the school until Harvard takes urgent action to address antisemitism on campus, part of a wave of challenges to colleges across the county in addressing hate speech sparked by the Israel-Hamas war. High-profile billionaire alumni like Pershing Square founder Bill Ackman and former Victoria’s Secret CEO Leslie Wexner have already said that if Harvard doesn’t take steps to fix the problem they could face a donor exodus, but now the largest group yet of alumni — most of whom do not have billionaire status — are threatening to withdraw their donations. “We never thought that, at Harvard College, we would have to argue the point that terrorism against civilians demands immediate and unequivocal condemnation,” wrote members of the Harvard College Jewish Alumni Association (HCJAA) in an open letter to President Claudine Gay and Dean of Harvard College Rakesh Khurana. “We never thought we would have to argue for recognition of our own humanity.” The HCJAA was formed last month in the wake of the school’s response to the October 7 attacks on Israel. Organizers say it is the first Jewish alumni association in the history of the university. The group is asking for Harvard to recognize their alumni association as a formal special interest group, share concrete plans to ensure the protection of Jewish students on campus and to officially adopt the International Holocaust Remembrance Alliance definition of antisemitism. “We now have a movement of over 1,600 alumni who are calling for meaningful reforms on campus to ensure that every student is safe.” Rebecca Claire Brooks, a co-founder of the HCJAA, told CNN. “This is a broad and growing intergenerational movement of alumni from many different sectors and industries. Yes, some of them are very influential donors and some of them are sort of more normal-sized donors. But we’re speaking in one unified voice in response to this moment,” she said. Harvard President Gay wrote a letter to members of the larger Harvard community addressing the tensions on Thursday. “Harvard rejects all forms of hate, and we are committed to addressing them,” she wrote. “Let me reiterate what I and other Harvard leaders have said previously: Antisemitism has no place at Harvard.” The school, she said, has “started the process of examining how antisemitism manifests within our community” and will “implement a robust program of education and training for students, faculty, and staff on antisemitism broadly and at Harvard specifically.” The school is also “seeking to identify external partnerships that will allow Harvard to learn from and work with others on our strategy,” she said. Harvard officials referred CNN back to Gay’s letter when asked for comment. Philanthropy’s impact Philanthropy is the single largest contributor to revenue at Harvard, accounting for 45% of the university’s $5.8 billion in income last year. Philanthropic gifts accounted for 9% of the university’s operating budget last year and 36% of its $51 billion endowment amassed over decades. While a large chunk of university donations come from big gifts, small donations from alumni are becoming an increasingly important source of funding for higher education, according to the Council for Advancement and Support of Education (CASE). About 95% of donations received by universities in 2022 were smaller than $5,000. Universities like to tout the high number of donations they receive to show that they have an engaged alumni base, said CASE. And while large donations are often restricted to specific purposes, such as a new building or facility, universities have more discretion with how they use smaller donations. “I wanted to make it possible for people, regardless of their income, to express their disappointment, their dissatisfaction or heartbreak with university,” said Brooks. “This is an egalitarian grassroots movement where any donor, no matter their religion or age, no matter how much they would otherwise normally contribute, can participate in the pledge in sending a clear signal that this type of toxic campus culture is detrimental to everyone.” Brooks told CNN that a number of similar groups from other universities have contacted her to start similar campaigns on their own campuses. More than 300 Cooper Union alumni also recently threatened to end donations over the New York school’s response to anti-Israel protests. In a letter sent to the school earlier this month, they accused the administration of being “more concerned with avoiding a scandal than protecting its Jewish students.” A Cooper Union spokesperson told CNN that the school is investigating “all reports of antisemitism, islamophobia, and other forms of discrimination urgently, thoroughly, and impartially.” “The safety and security of our students, faculty, and staff are our top priority, and we take every instance of discrimination that is reported to us seriously,” the spokesperson said.