The ratio of the atomic electric dipole moment (EDM) to a possible electron EDM has been calculated for the ground states of Cs, Xe and Hg, including to all orders the diagrams that involve only single excitations, while neglecting correlation effects, which require the simultaneous excitation of two or more electrons. The alkali atoms are known to have large enhancement factors and as a test of the procedure, a calculation was performed for the Cs ground state. The lowest experimental limit for an atomic EDM, so far has been established for the ground state of Xe, which is a closed-shell system, where the simple mechanisms for producing an atomic EDM from an electronic one are not available, but the interaction with the nuclear magnetic moment may still give an atomic EDM, which is here found to be about 10−3 of the electron EDM. For the heavier atom Hg, the effect is an order of magnitude larger.