In this speech, FRB Governer Lael Brainard suggested the following approach to monetary policy at the Effective Lower Bound:
.....I have been interested in exploring approaches that expand the space for targeting interest rates in a more continuous fashion as an extension of our conventional policy space and in a way that reinforces forward guidance on the policy rate. In particular, there may be advantages to an approach that caps interest rates on Treasury securities at the short-to-medium range of the maturity spectrum—yield curve caps—in tandem with forward guidance that conditions liftoff from the ELB on employment and inflation outcomes.....
She goes on to say:
To be specific, once the policy rate declines to the ELB, this approach would smoothly move to capping interest rates on the short-to-medium segment of the yield curve. The yield curve ceilings would transmit additional accommodation through the longer rates that are relevant for households and businesses in a manner that is more continuous than quantitative asset purchases. Moreover, if the horizon on the interest rate caps is set so as to reinforce forward guidance on the policy rate, doing so would augment the credibility of the yield curve caps and thereby diminish concerns about an open-ended balance sheet commitment. In addition, once the targeted outcome is achieved, and the caps expire, any securities that were acquired under the program would roll off organically, unwinding the policy smoothly and predictably. This is important, as it could potentially avoid some of the tantrum dynamics that have led to premature steepening at the long end of the yield curve in several jurisdictions.
I understand that this approach is different to traditional forward guidance in terms of time horizons. While Brainard does provide some elaboration as above, I am not entirely sure I understand all the policy implications, other than augmenting traditional forward guidance and quantitative easing. This NYT article says it is an activist move, for reasons that are not entirely clear to me.