A novel metal-free initiator, i.e, the salt of the tetrakis[tris(dimethylamino)phosphoranylidenamino]phosphonium (P-5(+)) cation with the 1,1-diphenylhexyl (DPH-) anion was prepared by cation metathesis. It initiates a very fast and controlled anionic polymerization of methyl methacrylate in THE Kinetic investigations between -20 and +20 degrees C using a flow tube reactor provide nearly linear first-order time-conversion plots with half-lives below 0.1 s, a linear dependence of the number-average degree of polymerization, and rather narrow molecular weight distributions ((M) over bar(w)/(M) over bar(n) approximate to 1.2). C-13 NMR measurements on a model of the active chain end (the P-5(+) salt of ethyl isobutyrate) in THF-d(8) show 15 and 25 ppm upfield shifts of the alpha-carbon compared to the dimers and tetramers of the lithium ester enolate, respectively, indicating a non-aggregated structure and an increased charge density on the alpha-carbon.