Abstract Low-energy multiple-collisional-excitation experiments have been performed on C 70 + and C 70 − at the ClusterTrap apparatus. The ions are stored in a Penning trap where they are excited via radial dipolar excitation before undergoing collisions with neutral argon atoms. The dominant decay mechanism for C 70 + (sequential loss of C 2-units) is compared with the dominant decay process of C 70 − (thermionic electron emission). A simple model based on the decay rates of the clusters is found to be in reasonable agreement with the experimental data obtained for the fragmentation process of the cationic fullerenes. The same model, when applied to the anions is observed to be in less agreement with the experimental results.