Investors often think of diversification as a free lunch—it allows them to maintain returns while reducing risk. But most people only get part of diversification right, and that can hurt them later in life.
With traditional diversification, people spread money around different kinds of investments to mitigate risk. That approach misses a key opportunity: “diversifying” how you invest over time.
Most people start investing with a small amount of money, because that is all they can afford, and ramp it up as their earnings grow. But investing so much later in life unnecessarily puts people at greater risk when they are close to retirement. They end up with far greater exposure to stock-market risk in their 50s and 60s than in their 20s and 30s, even if they are buying diversified mutual funds.
We propose a different method: People ought to borrow money to make their initial investments larger, so that they can invest closer to the same amount every year over their lifetime. Think of investing $2 a decade steadily for three decades, instead of $1 for the first, $2 for the next and $3 for the third.
…Sound risky? Consider that young people do the same thing with housing when they borrow money to buy a house they live in for decades—and there the leverage often involves borrowing $9 for every $1 of equity. We propose borrowing only $1 for each $1 invested. Limiting ourselves to 2:1 leverage means we don’t hit a perfectly even market exposure over time, but gets us closer to that ideal.
Most people won’t do this because unlike a home-mortgage it’s a non-standard idea. It could be standardized, however, with retirement planning products. Regardless, I agree with Ayres and Nalebuff that young people should be 100% in equities. Of course, the equity-basket should be diversified, national and internationally, and young people should follow a buy and hold strategy while being very aggressive on the equity-debt mix. Also, if, as you get older, you expect to make a bequest you should continue to be aggressive on the portion of your portfolio you expect be passed on to your beneficaries.