Two-dimensional upper limits on the frequency of black hole companions to solar-type stars as a function of orbital period and black hole mass, f_BH(M₂, P_orb). The existence of orbital periods close to 1 day is more tightly constrained than the existence of periods close to 3 days. Dark companions with masses M₂ < 3 M_⊙ are less tightly constrained than more massive companions, but above this limit the dependence on companion mass is weak.