Data Sources and Credits

The simulations are all made with the real historical data of the various assets.

The data used is mainly taken from:

  • Bogleheads forum – Simba’s backtesting spreadsheet (until 1972)
  • Market indexes, or Index Fund or ETF returns (from 1972 onwards)

The inspiration to build this website came from consulting a lot of material on the internet, but mainly we want to thank the sites listed below.

The Poor Swiss

Created by Baptiste Wicht, provides invaluable guides aimed at early retirement. There is also a simulator that allows you to check the success rate of any withdrawal rate. Unlike this website, a portfolio rebalancing is never implemented in the simulations, but otherwise the logic of the simulations (monthly withdrawal) is the same.

Portfolio Charts

Created by Tyler, is an authority on building lazy portfolios. Countless metrics are calculated for each portfolio, including SWRs and PWRs. Unlike this website, the indicated PWRs are calculated on the same worst period to which the SWRs refer, and the data sources start from 1972.

Early Retirement Now

Created by Karsten (Big ERN), is a real encyclopedia on early retirement. The website is full of articles and useful links: in particular, the author has created a google sheet that allows you to calculate all kinds of statistics concerning safe withdrawal rates. Furthermore, SWRs are calculated analytically and not iteratively (and we share this approach).