We evaluate the effectiveness of portfolio mandates on equilibrium capital allocation. We show that the impact of mandates crucially depends on firms' demand elasticity of capital. In a production economy with constant returns to scale, firms' demand for capital is infinitely elastic, and mandates can significantly impact the allocation of capital across sectors despite having a negligible impact on the cost of capital. This is in sharp contrast to an endowment economy where inelastic demand for capital implies equilibrium price reactions to mandates, which significantly reduce their effectiveness. Within a canonical real-business-cycle model calibrated to match key asset-pricing and macroeconomic moments, we estimate that a significant portion of the mandate remains effective in shaping equilibrium capital allocation, even when there is little disparity in the cost of capital across sectors. Our analysis challenges the common practice of judging the effectiveness of portfolio mandates by their impact on firms' cost of capital.