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Trump often touts the time he spent at Wharton, and the letter noted that those who signed it are "outraged that an affiliation with our school is being used to legitimize prejudice and intolerance."
The letter continued: "Although we do not aim to make any political endorsements with this letter, we do express our unequivocal stance against the xenophobia, sexism, racism, and other forms of bigotry that you have actively and implicitly endorsed in your campaign."
The letter slammed Trump for bragging about his Wharton degree while espousing beliefs that those who signed the letter say are incompatible with Wharton values.
"Your discriminatory statements are incompatible with the values that we are taught and we teach at Wharton, and we express our unwavering commitment to an open and inclusive American society," the letter said.
Trump transferred into the Wharton School after two years at Fordham University in New York, and he graduated with a bachelor's degree in economics in 1968.
The University of Pennsylvania's student newspaper noted in an article last year that "despite Trump's repeated mention of Wharton, his own classmates hardly remember him."
The Associated Press has also noted Trump's complicated relationship with Wharton, pointing out that Trump holds an undergraduate degree from the school, not a graduate degree from Wharton's prestigious MBA program.