WHAT’S THE MOST important idea in personal finance? It’s hard to single out just one, but over the years, I’ve found the following dozen ideas to be among the most useful.
Whether it’s on TV or online, there’s never any shortage of market prognosticators. Especially during a bull market, everyone seems to have an opinion on where things are headed. The reality, though, is that people can only guess about how the economy, the market or any individual investment will perform. Convincing as they might sound, no one has a crystal ball. That’s why, when it comes to investing, I suggest taking an evidence-based approach, one that relies as much as possible on data and research rather than on the simple stories, anecdotes and sayings that are so prevalent among market commentators.
What does the data tell us? Among the most significant research in recent years is the work of Hendrik Bessembinder. In looking at the historical returns of stocks, he found that just a tiny fraction—only 4%—have accounted for the vast majority of the market’s gains over and above what Treasury bills paid, and the median stock actually delivered a negative return. This is one of the key reasons I recommend index funds rather than picking individual stocks or investing in an actively-managed fund. Identifying that 4% is almost impossibly difficult. But if you invest in a broad-based index fund, you’ll have a high likelihood of owning the next Apple or Nvidia.
Be careful not to miss the forest for the trees. The most important driver of investment risk and return for most people, most of the time, is asset allocation. In other words, the dollars you have in stocks vs. in bonds or in cash will almost always be the most consequential decision. It’s easy to lose sight of that, though, because so much of the investment commentary from day to day focuses on details like small differences in fund expenses or small differences in bond yields. To be sure, details can be important, but only after considering the big picture.
Another challenge in investing is that certain rules of thumb gain so much popularity that they end up being seen as rules rather than just guidelines. For example, some say that the percentage of a portfolio allocated to bonds should be equal to an investor’s age. To me, that’s illogical. Consider Bill Gates. He’s 70 years old, but it stands to reason that he shouldn’t have the same asset allocation as any other 70-year-old. Rules of thumb are useful as points of reference, but we shouldn’t lose sight of the fact that everyone’s situation is different, and our investments should reflect that. More to the point, don’t worry if you’re doing something different from the next person.
Buy insurance, but only to protect against losses you couldn’t absorb on your own. What does this mean in practice? In many cases, it’s possible to significantly cut insurance premiums by increasing deductibles. For example, if you have a seven-figure net worth, you might consider raising the deductible on your homeowner’s insurance to $5,000 or $10,000 or even more. Similarly, you might re-evaluate your life insurance as your net worth grows. You’ll likely become “self-insured” at some point, and then you could reduce or drop that coverage.
Personal finance is quantitative, but we should never make decisions based only on the numbers. For example, a common question is how much cash to keep on hand. While we could work out an optimal number on a calculator, that shouldn’t be the final answer. You should also consider what would provide you with peace of mind. That is equally important.
Be wary of the psychological pitfall known as recency bias. This is the tendency to extrapolate from recent experience and to downplay the possibility that things might change. The most famous example? In the late-1920s, when the stock market was booming, Yale University economist Irving Fisher declared that the stock market had reached a “permanently high plateau.” Just nine days later, the market crashed, ultimately dropping 89% from its peak.
Avoid high fees. The research firm Morningstar once wrote, “If there’s anything in the whole world of mutual funds that you can take to the bank, it’s that expense ratios help you make better decisions. In every single time period and data point tested, low-cost funds beat high-cost funds.”
Keep things simple. Most importantly, I would be wary of investments that aren’t easily understood. Not only can this help keep investment costs down, but it also makes it much easier to monitor your financial picture. Legendary fund manager Peter Lynch said it best: “Never invest in any idea you can’t illustrate with a crayon.”
Avoid “interesting” investments. So far this year, Wall Street has introduced more than 1,000 new exchange-traded funds (ETFs). How many of these are worth your attention? My guess is you could probably count them on one hand. More than 80% of these new funds are actively-managed, and more than 30% employ leverage. And there are more to come. Fund companies recently filed paperwork to create ETFs that will track the performance of major league sports teams. They won’t actually own shares in the teams; instead, they’re expected to rise and fall in response to each team’s wins and losses.
For years, I’ve argued that bitcoin isn’t a valid investment. Even though it’s gone way up since I first made that argument, I still feel the same way, and for the same reason: because it lacks intrinsic value. Unlike stocks or bonds, it doesn’t generate any dividends or interest. Bitcoin’s price is not anchored to anything measurable or tangible, and that’s why, in my opinion, its price is so volatile.
When it comes to investment risk, investors’ attention usually turns to the stock market. That makes sense, but as we’ve seen this year, bonds are not without risk. And unfortunately, the total-bond market index, which is often seen as the simplest, set-it-and-forget-it option, is one that carries quite a bit of risk. If you’re choosing bond investments, my recommendation is to pay attention to a metric known as duration. This tells you how sensitive a bond, or bond fund, will be to interest rate changes. In my view, investors should hold a sizable portion of their bond investments in a fund, or in individual bonds, with a duration of less than two years.
Adam M. Grossman is the founder of Mayport, a fixed-fee wealth management firm. Sign up for Adam’s Daily Ideas email, follow him on X @AdamMGrossmanand check out his earlier articles.
Thanks, Adam. Now if each one of these could be the beginning of a lecture to every high school student, we’d have a lot more financially savvy adults. I would mention compounding and investing early, too.
Adam M. Grossman is the founder of Mayport, a fixed-fee wealth management firm. Sign up for Adam’s Daily Ideas email, follow him on X @AdamMGrossman and check out his earlier articles.
Thanks, Adam. Now if each one of these could be the beginning of a lecture to every high school student, we’d have a lot more financially savvy adults. I would mention compounding and investing early, too.
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