Pie charts summarizing the (a) 3352 RMSTAR M dwarf primaries and (b) 305 RMSTAR M dwarf companions, colored by the number of GDR3 parameters pointing to hidden multiplicity—RUWE, IPDfmp, RV error, and NSS. 71.8% of RMSTAR primaries have no companion indicator flags, while the remaining 28.2% have one or more indicators. Two stars, rms 1519-1245 and rms 0754-2920, have all four. Of the known wide companions, 54.5% have no companion indicator, while the remaining 45.5% have one or more indicators.