Recent measurements of voltage fluctuations near the threshold of the Gunn instability in GaAs by Kabashima, Yamazaki, and Kawakubo yield a Gaussian distribution of fluctuations and an anomalous increase in the variance. These results confirm the qualitative predictions of the fluctuation–dissipation theory of molecular fluctuations. In this note, a quantitative calculation of the fluctuations below threshold is given. Only experimentally determined parameters are involved, and the results are in good agreement with experiment.