From 1940 to 2019, Americans’ life expectancy rose by almost 16 years, while the share of the U.S. population 65 and older grew from 9.8% to 16.7%. The elderly have progressively more healthy years to work. Most important, increased life spans have meant that older Americans’ wealth portfolios have been able to compound for longer.

To illustrate, consider a 65-year-old today who has a portfolio of $1 million, fully invested in an S&P index fund, enabling him to hold off for years shifting assets into lower yielding bonds. Suppose he chooses to work an additional 10 years, expecting almost the same number of retirement years as a 65-year-old had in 1940, but all the while allowing the $1 million portfolio to compound for 10 years. If the S&P increases at its historical inflation-adjusted rate of 7.2%, his real wealth will grow to about $2 million—without any additional investments. The retiree will move from the top 12% of wealth holders to the top 6%. The person with $6 million at 65 will move from the top 3% to the top 1% at 75.

Source: Richard McKenzie, Americans are Living Longer and Prospering, Wall Street Journal.