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Is it time to forget what you learned about investing in bonds?

The stock market has had a wild ride this year, and more turbulence could lie ahead, what with a rancorous presidential election nearing and possibly more economic damage if a second COVID-19 wave hits.

But it might be the bond side of your portfolio where surprise risks lurk.

Bond yields have dropped so much in recent years, especially on government debt, that their income and diversification benefits are questioned.

U.S. Treasurys and other government bonds now yield less than what you can get from many dividend-paying stocks, and they might not cushion a portfolio from stock-market setbacks as you might expect. A traditional portfolio mix allocated to around 60% stocks and 40% bonds could prove disappointing.

"What’s the rationale for bonds when yields are close to zero or even negative?" asked Nicolas Rabener of Factor Research in a blog for the CFA Institute, an investment-professional organization. "It’s simply an asset class with no positive expected returns."

Bonds are less volatile than stocks, of course. But most of the arguments in favor of including bonds in a diversified portfolio, he noted, are based on the past four decades or so, when a lengthy, sustained decline in interest rates made them appealing. Bond prices rise when rates decline, boosting their returns. But prices fall when rates rise, which appears the more likely scenario going forward.

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Rethinking investment basics

The historic relationship between stocks and bonds is a fundamental building block of modern investment theory that helps shape decisions such as how to allocate investment dollars, Bank of America Securities noted in a report. But that relationship is changing, raising the question of whether the traditional investment mix of 60% stocks and 40% bonds is "dead," the report said.

The historic relationship between stocks and bonds is a fundamental building block of modern investment theory that helps shape decisions.
The historic relationship between stocks and bonds is a fundamental building block of modern investment theory that helps shape decisions.

Not everyone holds 60% of their investments in stocks (including various subcategories such as small companies or foreign stocks). Nor do they hold 40% in bonds including Treasurys, corporates, municipals, foreign debt and so on.

Rather, 60/40 is just one prominent rule of thumb. Another is holding a percentage equal to 100 minus your age in stocks, which would work out to 40% in stocks and 60% in bonds if you are age 60, for example. Regardless of the model, the idea is to include bonds with your stocks to dampen volatility and increase income.

But the 60/40 rule, among others, is being questioned now because bonds might not hold up their end of the bargain. Yes, stocks might be overvalued, but investors expect risks with them. They aren't so accustomed to dangers on the fixed-income side.