Ratios of K$^{*\pm}$/K$^0_{\rm S}$ and K$^{*0}$/K$^0_{\rm S}$ yields in pp collisions at $\sqrt{s} = 13$ TeV as a function of the average charged-particle multiplicity density at midrapidity $\langle {\rm d}N/{\rm d}\eta \rangle_{|\eta|< 0.5}$. Bars represent statistical uncertainties, open boxes represent total systematic uncertainties, and shaded boxes are the systematic uncertainties uncorrelated with multiplicity. The measurements are also compared to predictions from the PYTHIA6, PYTHIA8, EPOS-LHC, and DIPSY event generators. The prediction from EPOS-LHC for K$^{*0}$/K$^0_{\rm S}$ ratio distribution reported in [30, 37$-$39] is also shown.