How to report GPA, if minimum letter grade credits not reached? How would a graduate student, at the University of California, Santa Cruz, report their GPA, on fellowship applications, if they have not yet accrued enough letter grade credits? 

UCSC seems to not report a formal GPA until the student takes 25 credits of letter grade classes. This excludes credits received from pass / fail classes, which count toward graduation but not toward the 25 credit letter grade GPA threshold.
It seems the National Defense Science and Engineering Graduate (NDSEG) Fellowship states:


  What GPA do I enter for my school if I just started attending? You can
  enter 0.0 as your GPA – reviewers will understand that you have not
  yet received a GPA for that school and will not view it negatively.
  Link: https://ndseg.asee.org/faq/academic_background_section


Will follow-up if I receive any formal statement from the UCSC Office of the Registrar.