Expected multiplicity ratio (﹩\left\langle {f}_{\gt 1}/{f}_{1}\right\rangle ﹩ in Equation (2)) for different inclination dispersions drawn from a Fischer distribution and periods of outer nearest neighbor. The left panel shows that the inner planet is a USP planet (P_inner < 1 day). In the right panel, we set ﹩{P}_{\mathrm{inner}}\in [1,2]﹩ days. The inner planets are assumed to have one extra outer companion in the indicated period range. The shaded region indicates the observed ratio with Poisson error for our sample with M_s > 0.75 M_⊙, showing that the outer companions of USP planets are likely beyond ∼10 days.