Fama/French Data Library

The library is the reference source for the Fama/French factors, alongside hundreds of univariate, bivariate and three-way portfolios sorted on size, book-to-market, operating profitability, investment, E/P, CF/P, dividend yield and prior returns; the five-factor and momentum series are published for the US and for seven developed and emerging regions. Every dataset is a zip of CSV and TXT files under a stable /ftp/ path and downloads with a single unauthenticated GET; pandas-datareader’s FamaFrenchReader targets exactly those URLs.

Rights: the page carries the line “Copyright Eugene F. Fama and Kenneth R. French” and nothing else — no terms of use, no license grant, no redistribution permission. Treat it as all rights reserved by default and link to the source rather than mirroring the files. The series are derived from CRSP and Compustat, so downstream commercial use may also implicate those vendors’ terms.

Two practical notes. The files are legacy-shaped: multi-line preambles and several stacked tables per file, with annual sections following monthly ones, so a naive read_csv fails — which is why the pandas-datareader wrapper matters. And from the January 2025 release the library switched from CRSP’s Legacy (FIZ) format to Stock and Indexes Flat File Format 2.0 (CIZ), changing monthly returns from month-to-month holding period returns with dividends reinvested at month-end to compounded daily returns with dividends reinvested on their ex-dates; series pulled before and after that release are not strictly comparable, and Legacy-format history is offered separately. Coverage advances every month — the dates above are the 202606 CRSP vintage, checked 2026-08-17.