In this paper, we investigate how, in a stylised theoretical framework, an increase in the degree of globalization - modelled as a deline in trade costs - affects the real natural rate of interest by impacting firms markups. Outlining a two- country dynamic general equilibrium model with endogenous elasticity of substitution between goods, we suggest two main propositions: 1) Globalization - via the impplied variation in markups - has a potentially significant impact on the natural rate of interest. 2) Simple, plausible markup dynamics may have contributed to explain the recent "conundrum" of world interest rates.