All University employees are subject to Office of the President's Policy on Acceptance or Offering of Gifts and Gratuities by University Employees that states in part:

It is the policy of the University of California that its officers and employees shall comply with the provisions of state and federal law governing the acceptance of gifts and gratuities. In addition to compliance with the requirements of law, University officers and employees must avoid the appearance of favoritism in all of their dealings on behalf of the University. All University officers and employees are expected to act with integrity and good judgment and to recognize that the acceptance of personal gifts from those doing business or seeking to do business with the University, even when lawful, may give rise to legitimate concerns about favoritism depending on the circumstances.

Gifts include meals, tickets, travel, and discounts given by vendor reps for personal items unrelated to the University business. The term gift or gratuity does not include information materials such as books, reports, pamphlets, calendars, periodicals, or other unsolicited promotional material.

For further details, visit:
https://policy.ucop.edu/doc/1200366
https://www.policy.ucsb.edu/files/docs/policies/gifts-accept-offer.pdf