  Supersymmetric contribution to the CP asymmetry of B_d \to \phi K_S is
re-examined. It is emphasized that our analysis takes into account the recently
found constraint from the mercury electric dipole moment, in addition to the
well-known constraint from the branching ratio of b \to s \gamma. We show that,
despite these constraints, the CP asymmetry can considerably deviate from the
Standard Model prediction, if the CP-odd flavor mixing comes from left-handed
squarks. Alignment mechanism of sfermion masses and mixing may imprint the
required flavor mixing at high energy scale.
