- None of the UHE neutrinos detected thus far by ICECUBE came from identifiable GRBs. It is noted here that, because the GRB luminosity function is top heavy, this limits the fraction of GRB energy that goes into neutrinos (in the detectability range of ICECUBE) to a small fraction (≲0.15) of the GRB photon energy, but does not yet constrain any scenario that converts baryonic outflow from GRB to UHE neutrinos. © 2015. The American Astronomical Society. All rights reserved..