We present theoretical results on the triple ionization of carbon mono
xide providing new insights for the understanding of the available exp
erimental data on the triple ionization cross section and the fragment
ation patterns of trications. A large number of electronic states are
shown to contribute. These are computed by a newly implemented Green's
function approach for the efficient ab initio calculation of very man
y triply ionized states needed in the theoretical investigations of mo
lecular multiple ionization processes.