Most of the time this should not  8  BIS central bankers’ speeches  happen, as both aggregate demand and credit market shocks will tend to push the two policies in the same direction. Differential movements are more likely to arise in the face of supply disturbances. For instance, a beneficial supply shock will tend to push inflation below target, warranting a looser monetary policy, while it may also encourage a credit boom, warranting tighter macroprudential policies. But in any case, it is not clear that is such a problem. The instruments address different distortions, so one should expect them to move in different directions from time to time. Moreover, it is likely that the regulatory dials will be adjusted much less frequently than policy rates, so co-ordination should not be that significant an issue7. My concluding observations relate to the broader context within which macroprudential policies are conducted. Credit booms are times when everyone feels good and risks seem slight. Taking the credit punch bowl away before the party gets out of hand will be controversial, and banks and borrowers will be quick to claim “this time is different”. That is a good reason for delegation to a separate committee or agency with a longer perspective, much as we do with monetary policy. Even so, the pressures not to take action may be intense. Making macroprudential policies rule-based would be one response.
Introducing – or rather re-introducing – financial considerations to the analysis of macroeconomic fluctuations would also be returning the study of the business cycle to its historical roots. This task is already well under way in academia and I suspect the field of macroeconomics will look very different in a decade or so. We are, though, still in the foothills. But to give a broad-brush flavour of how financial intermediaries might affect things, we can look to the graphical extension of the New Keynesian model offered by Woodford (2010). The left-hand panel of Chart 6 shows the demand for funds from ultimate borrowers, LB, together with the total supply of loanable funds from savers, LS. The former is a decreasing function of the cost of borrowing, RB, while the latter is an increasing function of the return on savings, R. For simplicity, I shall take this to be the return on deposits and the same as the central bank’s policy rate. The marginal source of funds to intermediaries, however, is likely to be in the wholesale markets and, if unsecured, these will need to offer a higher return to compensate for the associated default risk. 4  BIS central bankers’ speeches  In the standard model with costless financial intermediation, the loanable funds market clears at A and the borrowing and saving rates are equal.