A bedrock of long-term investing, a portfolio split 60/40 between equities and high-quality bonds, is set for its worst monthly slide since the market meltdown in the early days of the pandemic.
Both equities and bond prices have fallen sharply this month as markets price in a faster pace of interest-rate tightening during 2022 from the Federal Reserve.
The central bank's hawkish pivot from mid-December intensified after last week's policy meeting, with leading Wall Street economists calling for at least five and possibly as many as seven quarter-point rate hikes this year.
The Bloomberg 60/40 index has lost 5.4% in January, reflecting a decline of 6.75% for large cap equities and a loss of 2.1% for the Bloomberg U.S. Aggregate bond index.
That's the worst showing since a slump of 7.7% in March 2020, when pandemic lockdowns plunged the economy into a brief recession.
Investors believe much rests with how far the Fed tightens policy and to what degree the pace of inflation, economic growth and corporate earnings slows during the coming interest-rate hiking cycle.
Elevated inflation may force the Fed to become more aggressive and spur higher market volatility that could erode the performance of diversified portfolios for an extended period.
"We could be looking at stagflationary environment where both equities and bonds fall as a result of persistent inflation and low growth," said Nancy Davis, chief investment officer at Quadratic Capital Management.
Investors owning a long term mix of equities and bonds only need to look back to 2018 for how Fed tightening can spark negative returns.
The 60/40 strategy suffered a decline of 2.3% in 2018, only its second annual loss since the Bloomberg index was established in 2007. The other was during the credit-market crisis of 2008.