Building a nest egg by rebalancing a standard mix of stocks and bonds—the “set it and forget it” method of the past 40 years—is not going to work as well as it has in the past, The Wall Street Journal reported.

The drop in longer-term Treasury bonds’ values, combined with the expense of stocks, are causing investors to lower their expectations.

The summer of 2020 was the high point of “set it and forget it,” caused by the quickest return to a bull market in history and record low long-term Treasury yields, which bolstered bond funds. In that year, a classic stock-bond split consisting of 60 percent stocks on the S&P index and 40 percent 10-year Treasury notes (a 60/40 portfolio)  earned 15.3 percent.

Millions of new stock investors—young people stuck at home during the pandemic with extra savings who opened brokerage accounts, according to the Journal—took advantage of the huge federal debt, more than $21 trillion in 2020, and zero percent overnight interest rates that remained at that rate until 2022.

By January 2021, an index of unprofitable companies maintained by Goldman Sachs Group had rallied by nearly 300 percent in nine months, a sign that money had become too cheap. By last year, the massive budget deficits and zero percent interest rates had stoked the highest inflation in 40 years, forcing the Federal Reserve to raise interest rates.

Back in 1981, persistently high inflation led the Fed to raise overnight interest rates above 19 percent, a figure that descended over the next four decades. That gave rise to the “gospel” of the classic balanced portfolio: An investor who put $1,000 into a 60/40 portfolio at the end of 1981, even after adjusting for inflation, had $18,728 by the end of 2020, the Journal reported. The portfolio would have lost money in only five of those years.

“You have to have been working for more than 43 years, and thus be over 65, to have seen a prolonged period that was otherwise,” investor Howard Marks, the co-founder of Oaktree Capital Management, wrote in a recent note to clients, the Journal reported.

In the mid-1960s, stock valuations were at their most expensive level in decades based on a cyclically adjusted formula devised by Nobel Prize-winning economist Robert Shiller, with stocks being expensive and inflation lurking. Accordingly, a family setting aside $1,000 for their toddler’s education at the end of 1965 in a 60/40 portfolio ended up with only $785 in real terms by her senior year of high school in January 1982.

It looks almost the same today, as last year was one of the worst ever in real terms for a 60/40 portfolio.

According to the Journal, investors should probably lower their return expectations and go on the defense. That would still mean balancing a mix of safer and riskier investments, but the mix would be different. Because short-term Treasury bills are currently less volatile than-long-term bonds, they could make up a larger part of the mix.

In addition, the traditionally risky part of the 60/40 portfolio—stocks—may actually be safer, relatively speaking. They cratered in the inflationary 1970s, but they are more resilient to inflation than bonds.