  We report on a search for high-energy counterparts to fast radio bursts
(FRBs) with the Fermi Gamma-ray Burst Monitor (GBM), Fermi Large Area Telescope
(LAT), and the Neil Gehrels Swift Observatory Burst Alert Telescope (BAT). We
find no significant associations for any of the 23 FRBs in our sample, but
report upper limits to the high-energy fluence for each on timescales of 0.1,
1, 10, and 100 s. We report lower limits on the ratio of the radio to
high-energy fluence, $\frac{f_{r}}{f_{\gamma}}$, for timescales of 0.1 and 100
s. We discuss the implications of our non-detections on various proposed
progenitor models for FRBs, including analogs of giant pulses from the Crab
pulsar and hyperflares from magnetars. This work demonstrates the utility of
analyses of high-energy data for FRBs in tracking down the nature of these
elusive sources.
