Number of satellites M_V < −7.5 mag around nearby MW-like galaxies as a function of density contrast-weighted mass ﹩{M}_{{\rm{h}}}^{k{{\rm{\Theta }}}_{5}}{M}_{\odot }﹩, where M_h is the kinematically derived halo mass, and Θ₅ is the tidal index from the five closest neighbors. The best-fit slope is 10.19 and the best-fit weight is k = 0.77. The colors display Θ₅ on its own for the sample. The Pearson correlation is r = 0.889 (∼4.6σ). The included galaxies are M31, NGC 1023, NGC 253, NGC 2683, NGC 2903, NGC 3031, NGC 3115, NGC 4258, NGC 4594, NGC 4631, NGC 4736, NGC 5055, NGC 5236, M101, NGC 628, and NGC 891. NGC 2903 may be an outlier, with a relatively isolated environment but a high tidal index. M101 fits well in the trend.