IMF Working Papers describe research in progress by the author(s) and are published to elicit
comments and to encourage debate. The views expressed in IMF Working Papers are those of the
author(s) and do not necessarily represent the views of the IMF, its Executive Board, or IMF management.
IMF Working Papers describe research in progress by the author(s) and are published to elicit
comments and to encourage debate. The views expressed in IMF Working Papers are those of the
author(s) and do not necessarily represent the views of the IMF, its Executive Board, or IMF management.
This paper analyzes the use of unconventional policy instruments in New Keynesian setups in which the ‘divine coincidence’ breaks down. The paper discusses the role of a second instrument and its coordination with conventional interest rate policy, and presents theoretical results on equilibrium determinacy, the inflation bias, the stabilization bias, and the optimal central banker’s preferences when both instruments are available. We show that the use of an unconventional instrument can help reduce the zone of equilibrium indeterminacy and the volatility of the economy. However, in some circumstances, committing not to use the second instrument may be welfare improving (a result akin to Rogoff (1985a) example of counterproductive coordination). We further show that the optimal central banker should be both aggressive against inflation, and interventionist in using the unconventional policy instrument. As long as price setting depends on expectations about the future, there are gains from establishing credibility by using any instrument that affects these expectations.