48 CFR 3.101-2: 3.101-2 Solicitation and acceptance of gratuities by Government personnel.

As a rule, no Government employee may solicit or accept, directly or indirectly, any gratuity, gift, favor, entertainment, loan, or anything of monetary value from anyone who (a) has or is seeking to obtain Government business with the employee's agency, (b) conducts activities that are regulated by the employee's agency, or (c) has interests that may be substantially affected by the performance or nonperformance of the employee's official duties. Certain limited exceptions are authorized in agency regulations.