End-group analyses of the oligo- and polypropylenes produced with bis(phenoxy-imine)Zr and Hf complexes with methylaluminoxane (MAO) indicate that the polymerization is initiated by two consecutive 1,2-insertions and is terminated by a beta-H transfer following a 2,1-insertion. Our data indicate that chain propagation occurs with prevailing 1,2-regiochemistry but with considerable regioerrors, and with virtually no stereoselectivity.