In-medium subthreshold K¯N scattering amplitudes calculated within a chirally motivated meson–baryon coupled-channel model are used self consistently to confront K− atom data across the periodic table. Substantially deeper K− nuclear potentials are obtained compared to the shallow potentials derived in some approaches from threshold K¯N amplitudes, with ReVK−chiral=−(85±5) MeV at nuclear matter density. When K¯NN contributions are incorporated phenomenologically, a very deep K− nuclear potential results, ReVK−chiral+phen.=−(180±5) MeV, in agreement with density dependent potentials obtained in purely phenomenological fits to the data. Self consistent dynamical calculations of K−–nuclear quasibound states generated by VK−chiral are reported and discussed.