Left image illustrates the mass ratio distribution computed for the currently known VLM binary systems, based on the online VLM Binaries Archive ( http://www.vlmbinaries.org) as of 2009 July. Spectroscopic binaries without known mass ratios were excluded. The distribution shows clear evidence of a peak near unity. The shaded bins represent the systems with age estimates ⩽10 Myr, which have on average larger separations compared to the older binary systems. The right image displays the comparison of mass ratio distributions for G stars, early-M stars and ultracool dwarfs, as adopted from Allen (2007). The mass ratio appears to increase with decreasing mass of the primary.