Observed spectrum of HIP 65426 b (coloured squares) compared to the best-fit spectral model from the BT-Settl grid, with T_eff = 1618 K, log g = 3.78 and R = 1.17 R_J. The horizontal error bars show the width of the SPHERE and NACO filters, and the grey squares show the predicted flux calculated using the filter transmission curves. Several models drawn from the MCMC posterior distributions are also shown in grey.