The concentration dependences of 133Cs and 19F chemical shifts for aqueous solutions of cesiumperfluorooctanoate are analyzed by using a two-state model to ascertain the results in our previous studyon the same system which demonstrates micellar growth along two dimensions based on the analysis ofsmall-angle X-ray and neutron scattering. The distribution of counterions has also been calculated byusing a cell model combined with the Poisson−Boltzmann equation. The results are consistent with theincrease in the degree of counterion binding with increasing surfactant concentration, which may berelated to the two-dimensional growth of micelles.