predicated by focusing only on macroeconomic stability. As illustrated by the left-hand panel ofFigure 7, assuming that the weight attached to macroeconomic and financial stability is the same,average lending interest rates would fall by less than in the flex-rates case. Therefore, under thisregime, our model is consistent with Taylor’s argument in the sense that it suggests keeping in-terest rates higher than the flex-rate case to avoid excessive borrowing and large asset price in-creases, and to reduce the probability of a crisis if the economy is hit by a negative shock in thefuture.The results are different when the policy-maker has two separate instruments to address financialand macroeconomic friction. As noted above, this is equivalent to the case in which there are twoseparate and independent policy authorities, such as a central bank with the objective of price sta-bility and a financial regulator with the objective of financial stability. As we discussed above, inthis case, the policy-maker can achieve efficiency with two independent policy actions, regardlessof the sign of the shock. Therefore, once the excess borrowing generated by the financial frictionis addressed with a macro-prudential tool, it is optimal for the central bank to lower interest ratesin order to address interest rate stickiness and restore the flex-rates allocation. As a matter of fact,the right-hand panel of Figure 7 displays how the average lending rate under this regime (dashedline) is effectively equal to the one prevailing under the flexible interest rates (solid line).In the United States, institutional responsibility for financial stability is shared among a multiplic-ity of agencies. Therefore, for Taylor’s contention to be justified within our model, we wouldhave to observe an effective regulatory clampdown on mortgage lending during the period inwhich monetary policy was unusually lax by the standard of the Taylor rule. As we shall see be-low, the regulatory effort to contain mortgage lending during the period 2003-06 was at best inef-fective, if not absent altogether. The evidence we report, therefore, provides support for the ideathat regulation (or, more exactly, the lack thereof) was a key factor in determining the magnitudeof the boom-bust cycle experienced by the U.S. housing market rather than monetary policyperse.Since the Glass-Steagall Act of 1932, U.S. depository institutions (e.g., banks, thrifts, creditunions, savings and loans, etc.) have been regulated by different federal agencies.17In contrast,non-depository mortgage originators have enjoyed much more freedom even when they weresubsidiaries of bank holding companies (see Engel and McCoy, 2011, Demyanyk and Loutskina,2012). Moreover, as it is well known, the rise of securitization was accompanied by a shift in