The European Central Bank published Working Paper No 3138 by Luca Fosso presenting a trend-cycle vector autoregression framework to separate permanent (trend) and transitory (business-cycle) drivers of US macroeconomic fluctuations for policy analysis. The paper is published as research and does not represent the views of the ECB. The approach replaces deterministic long-run components used in standard structural VARs with time-varying stochastic trends and imposes theory-guided long-run comovement restrictions consistent with a New Keynesian framework and a Fisher relationship. Using quarterly US data from 1960Q1–2023Q4 on output, consumption, inflation, one-year-ahead inflation expectations, the three-month Treasury yield and commodity prices, the model produces gap measures and shock decompositions; it reproduces stylised facts such as lower trend growth since the 2000s and a secular decline in the real natural rate since the late 1990s. For the post-pandemic episode, the paper finds inflation was mostly cyclical with no evidence of trend inflation drifting away from a 2% target, and attributes the bulk of the inflation surge to demand shocks, with supply shocks important but largely confined to early recovery and the period around Russia’s 2022 invasion of Ukraine; accommodative monetary policy contributes to the surge and tightening contributes to disinflation. A real-time exercise suggests that adding inflation expectations reduces uncertainty and limits subsequent revisions to trend inflation estimates after 1982. A counterfactual specification that forces deterministic trends materially changes conclusions, producing persistently negative post-2008 output gaps and shifting the post-pandemic inflation surge towards supply-driven explanations.