The observed reactivity patterns of small MAO sheets towards anionization explain the relative intensities of anions detected during early-stage ESI-MS monitoring of Me3Al hydrolysis. This correlation becomes particularly clear when considering both ionization energies and neutral precursor stabilities in polar media. However, a quantitative prediction of intensity differences remains challenging, likely due to complex factors. Perhaps the most important factor is the actual mechanism for competitive hydrolysis vs. aggregation of the neutral MAO molecules formed.