Central banks have a primary goal of price stability. They pursue it using tools that include the interest they pay on reserves, the size and the composition of their balance sheet, and the dividends they distribute to the fiscal authority. We describe the economic theories that justify the central bank’s ability to control inflation and discuss their relative effectiveness in light of the historical record. We present alternative approaches as consistent with each other, as opposed to conflicting ideological camps. While interest-rate setting may often be superior, having both a monetarist pillar and fiscal support is essential, and at times pegging the exchange rate or monetizing the debt is inevitable.

Long-dated inflation swap contracts provide widely used estimates of expected inflation. We develop methods to estimate complementary tail probabilities for persistently very high or low inflation using inflation options prices. We show that three new adjustments to conventional methods are crucial: inflation, horizon, and risk. We find that: (a) U.S. deflation risk in 2011–2014 has been overstated, (b) ECB unconventional policies lowered deflation disaster probabilities, (c) inflation expectations deanchored in 2021–2022, (d) reanchored as policy tightened, (e) but the 2021–2024 disaster left scars, and (f) U.S. expectations are less sensitive to inflation realizations than in the eurozone.