What is cost-push vs demand-pull inflation?

Inflation can be driven by the supply side (cost-push) or the demand side (demand-pull), and distinguishing between the two is critical for the appropriate policy response. Cost-push inflation occurs when the costs of production rise, forcing businesses to increase prices to maintain margins. Common causes include oil price spikes, supply chain disruptions, rising wages in tight labor markets, tariffs on imported goods, and weather-driven agricultural shortages.

Demand-pull inflation occurs when aggregate demand exceeds the economy's capacity to produce goods and services. This can result from fiscal stimulus (government spending or tax cuts that boost disposable income), loose monetary policy (low interest rates that encourage borrowing and spending), wealth effects (rising asset prices making consumers feel richer), or external demand booms. When too much money chases too few goods, prices rise.

The policy implications differ substantially. Demand-pull inflation responds well to monetary tightening: higher interest rates reduce borrowing, cool spending, and bring demand back in line with supply. Cost-push inflation is more problematic for central banks because raising rates does not fix supply constraints; instead, it adds demand destruction on top of the supply shock, potentially causing stagflation. The optimal response to pure cost-push inflation may be to look through the temporary price shock rather than tighten, though this requires confidence that inflation expectations remain anchored.

The 2021-2023 inflation episode featured both types simultaneously, creating an unusually complex policy challenge. Supply chain disruptions and energy price spikes (cost-push) combined with massive fiscal transfers and ultra-easy monetary policy (demand-pull). The debate over which driver dominated shaped the "transitory" vs "persistent" inflation argument and influenced the Fed's initial hesitancy followed by aggressive tightening. Ultimately, resolving the inflation required both supply chain normalization (addressing cost-push) and monetary restriction (addressing demand-pull).