Figure 6EFFICIENTALLOCATION WITHBOTHFRICTIONS: NEGATIVESHOCK TO THEINTERESTRATE. On the horizontal axis is the maximum size of the endowment shock (e). The thin lines withtriangle and square markers display the equilibrium after a negative shock hits the risk-free rate underflex-rates and sticky rates, respectively; the dashed line displays the efficient allocation with two policyinstruments. A subsidy is in place to remove the distortionary effect of monopolistic competition.D THETRADE-OFF: ADDRESSINGBOTHFRICTIONS WITHONEINSTRUMENTLet us now consider the case in which both frictions are present in the model but the interest rateis the only instrument at the policy-maker’s disposal.Before proceeding it is useful to recall that, in our model, the financial friction results in moreborrowing than socially desirable in period 0 when the collateral constraint has a positive prob-ability to bind in period 1, regardless of the sign of the shock. In contrast, the macroeconomicfriction generates either more or less borrowing than socially desirable depending on whether theeconomy is hit by a positive or a negative shock. It is thus evident that, if the policy-maker hasonly one instrument, she/he may face a trade off in the face of negative shocks when the economyrequires interventions in opposite direction.Consider a positive shock to the risk-free interest rate. As we showed before, both the macroe-conomic and the financial friction result in higher borrowing in period 0 relative to the sociallyefficient allocation. To address the macroeconomic friction, the policy-maker can raise interestrates by the factory= (1m)u=m>0, as implied by equation (18); and, to address the financia