"By employing leverage to gain more exposure to stocks when young, individuals can achieve better diversification across time. Using stock data going back to 1871 we show that early leverage combined with reduced equity exposure when older can reduce lifetime portfolio risk"

You can pretty easily go buy an ETF that offers twice the daily return of the S&P 500 index. As we have discussed, holding a daily 2x S&P ETF for 30 years probably will not give you twice the 30-year performance of the S&P: These funds rebalance every day, creating “volatility drag” that can reduce returns. But, you know, maybe? The 10-year total return of the ProShares 2x S&P 500 fund is about 18.3% per year; the equivalent for an unlevered S&P 500 fund is about 12.4%: You’re not exactly getting 2x exposure, but you’re getting more than 1x.

This is extremely not investing advice but I am passing it along because these ETFs are all plastered with warnings saying “this is intended to be held for one day and will get real weird after that,” and putting them in a 401(k) to hold for decades is among the more counterintuitive things that my readers have found to do with their personal accounts.