BU’s GPA requirements for their Economics PhD students:

GPA Requirements
All courses must be passed with a grade of B- or higher. The core average must be pi (3.1416) and an overall grade point average (GPA) of 3.0 for the M.A.P.E. and the Ph.D. must be attained in all courses taken after enrollment in the Graduate School at Boston University. At the end of each academic year, a student’s course grade average is reviewed. Failure to maintain satisfactory standing results in recommendation for termination from the Ph.D. program.

Awesome.