Michael Lewis’ latest book Going Infinite: The Rise and Fall of a New Tycoon is an entertaining account of the journey of Sam Bankman-Fried and his cryptocurrency trading firm FTX.  Lewis’ many critics wanted the story to be a deep dive into Sam’s criminal activity and fraud within the cryptocurrency industry, but that’s not the story Lewis is telling. Relative to social and business norms, Sam is an outlier of huge proportions.  So much so, that his meteoric rise in the cryptocurrency business world would have seemed impossible in advance.  This is the story Lewis told. However, Sam is currently on trial for (allegedly) swindling billions from traders and investors.  Those most interested in this story wanted to learn more details of the swindling. Some critics accuse Lewis of having been taken in by Sam.  I didn’t get this from the book.  Lewis did discuss Sam’s seeming transgressions, he just didn’t dwell on them because they weren’t central to the stor...

The origin of the so-called 4% rule is WIlliam Bengen’s 1994 journal paper Determining Withdrawal Rates Using Historical Data .  Experts often criticize this paper saying it doesn’t make sense to keep your retirement withdrawals the same in the face of a portfolio that is either running out of money or is growing wildly.  However, Bengen never said that retirees shouldn’t adjust their withdrawals.  In fact, Bengen discussed the conditions under which it made sense to increase or decrease withdrawals. Bengen imagined a retiree who withdrew some percentage of their portfolio in the first year of retirement, and adjusted this dollar amount by inflation for withdrawals in future years (ignoring the growth or decline of the portfolio).  He used this approach to find a safe starting percentage for the first year’s withdrawal, but he made it clear that real retirees should adjust their withdrawal amounts in some circumstances. In his thought experiment, Bengen had 51 retire...