This study breaks new ground by combining three substantial databases of commercial policy change over the past decade to compute the shares of Commonwealth exports at risk from adverse policy changes and reforms by trading partners. The calculations undertaken for this study use the finest-grain trade data available globally, and the conservative methods employed imply that the resulting estimates almost certainly understate the scale of the threat to living standards. The study demonstrates that larger shares of Commonwealth member countries’ exports have been exposed to changes in other policies, undertaken by their trading partners, that have tilted the commercial playing field towards favoured, local firms.