Datapoints with errorbars represent the rotational velocity measured at the outermost HI radius, V_out,HI = V(R_out,HI), for six example galaxies. The galaxies are ordered from top left to bottom right in order of increasing R_out,HI. In each panel, the dotted and dashed lines correspond to the RCs of the most massive halo that is compatible with the observed datapoint within 1σ, assuming an NFW and DC14 profile respectively. The horizontal mark denotes the value of the linewidth-derived V_rot,HI for each galaxy.