Billionaire Ronald Lauder, a powerful financial backer of the University of Pennsylvania, is threatening to cut off donations if the school doesn’t do more to fight antisemitism, CNN has learned.

The threat from Lauder, one of the heirs to the Estee Lauder cosmetics company, marks the latest fallout from donors and alumni alarmed by a Palestinian literary festival that was held on campus last month prior to the Hamas terror attacks on Israel.

Even before the Palestine Writes Literature Festival started, UPenn leaders acknowledged it would include speakers with a history of making antisemitic remarks.