The neutral rate, written r* and pronounced r-star, is the interest rate that neither stimulates nor restrains the economy: the level at which monetary policy is doing nothing. It cannot be observed, only estimated, yet it anchors everything a central bank does. Whether a 4 per cent policy rate is tight or loose depends entirely on whether neutral is 2.5 per cent or 4 per cent, and that single disagreement explains much of the modern rates debate.
Why it matters
Central banks steer by the gap between the policy rate and neutral. Policy above r* should slow demand and inflation; below it, stimulate. When the Fed says policy is restrictive, it is making a claim about r*. If neutral has risen, because of larger fiscal deficits, an investment boom in AI infrastructure, or deglobalisation, then a rate that looks restrictive by pre-2020 standards may barely be braking the economy at all. That is one reading of why growth kept surprising through the mid-2020s hiking cycles.
Why nobody agrees on it
Estimates come from models, and the models disagree with each other and with themselves over time. The longer-run dot in the Fed’s projections is the committee’s own estimate, and it has drifted upward as members conceded the post-crisis era of ultra-low neutral may have ended. The honest answer is a range, roughly 2.5 to 4 per cent nominal in the current debate, which is an enormous span when markets price policy moves in quarter points.
What to watch
The longer-run dot in each Summary of Economic Projections, speeches that mention the neutral or natural rate, and the economy’s behaviour itself: if rates stay high and growth does not slow, the market gradually reprices r* upward, lifting long yields through the term premium and expectations channels together. R-star moves slowly, but when consensus about it shifts, everything priced off the risk-free curve shifts with it.