Chiral Symmetry Breaking and Stability of the Magnetized Vacuum

The recent claim [arXiv:hep-th/0603070, arXiv:hep-th/0605020] that there exists in QED a maximum magnetic field of 10^{42} G, above which the magnetized vacuum becomes unstable with respect to the so-called “positronium collapse” is critically examined and unequivocally refuted.