A Global Factor in National Inflation, 1995–2024: Principal Components, Random-Matrix Benchmarks, and Permutation Tests on 143 Economies

Using the World Bank WDI consumer-price inflation series (FP.CPI.TOTL.ZG; source update 8 October 2026) for a balanced panel of 143 economies over 1995–2024, I estimate a common inflation factor by principal components. The first component accounts for 35.7% of the variance of standardised, transformed inflation, and its time series correlates 0.98 with cross-country median inflation. A Marchenko–Pastur bound gives 10.1 as the largest eigenvalue expected without common structure; the observed value is 51.0. A circular-shift test that preserves each country's serial correlation puts the 99th percentile of the first-component share at 14.9%. The common factor is therefore not an artefact of persistence. Its share in rolling ten-year windows rose from 26–42% in 2005–2013 to 59% in 2015–2024. India's loading is weak (R² = 0.09), against a cross-country median of 0.34.