This paper studies the imposition of position limits on commodity futures from the perspective of curbing excessive speculation and thus manipulation. We present a simple general equilibrium model in a static rational expectations framework and agent heterogeneity to illustrate that excessive speculation serves to enrich other agents at the expense of the speculator. Position limits, on the contrary, are not only superfluous, but also counter-productive, as they exacerbate market power and lead to a deterioration in efficiency. Position limits not only reduce social welfare but also cannot restrain market manipulation.

This paper studies pension fund design in the context of investment in the debt and equity of a firm. We employ a general equilibrium framework to demonstrate that: (i) the asset location ‘puzzle’ is purely a partial equilibrium phenomenon, conceived in a risk neutral setting, that disappears with the introduction of sufficient risk aversion; (ii) the inability of policy makers to manage an economy with multiple firms yields a mixed equilibrium, where bonds are observed in both taxable and tax-deferred accounts; and (iii) the Pareto-efficient pension plan comprises of a defined benefit plan.