Bound-state β--decay is a rare radioactive process where the created electron is trapped in an atomic orbital instead of being emitted. It can be observed in highly ionized atoms in particular when normal beta-decay is energetically forbidden, but bound-state decay is still possible. In this work we present a systematic theoretical study on the bound-state β--decay of fully ionized atoms where key nuclear inputs include the nuclear shape factor (expressed through ft values) and the lepton phase-space volume function. We present a method to evaluate nuclear shape factor for fully forbidden β- transitions in neutral atoms, from the inverse electron capture process using the Takahashi–Yokoi model and account for the impact of electron capture to different atomic orbitals on the resulting half-lives. Decay rates for bound-state β--decays of nuclei 163Dy, 193Ir, 194Au, 202Tl, 205Tl, 215At, 222Rn, 243Am, and 246Bk are calculated, where the normal beta-decay is forbidden. In addition, we compute the bound-state β--decay rates for nuclei 187Re, 227Ac, and 228Ra, observing enhancements by factors of 102 to 104 relative to their neutral-atom counterparts. Our results show that the half-lives of certain bare nuclei are significantly shorter than those of the corresponding neutral atoms, identifying them as promising candidates for future experimental investigation. The theoretically predicted half-lives of the bound-state β--decay could provide valuable inputs for various astrophysical studies.