From Dimensional Fund Advisors

U.S. consumer prices were up by 5.4% for the year ending June 2021, the largest annual increase since August 2008.[1] Naturally, inflation is at the center of attention for many U.S. investors.

Inflation Outpaced

Exhibit 1 shows average real returns (that is, returns net of inflation) to different asset classes in years with high (above-median) inflation from 1927 to 2020. We consider a total of 23 U.S. assets that span bonds, stocks, industries, and equity premiums. Over this period, inflation averaged 5.5% per year in high-inflation years. While average real returns were mostly lower in years with high inflation compared to years with low inflation, the exhibit shows that all assets except one-month T-bills had positive average real returns in high-inflation years.

The analysis over 1927–2020 is useful because it covers periods with double-digit U.S. inflation (like the 1940s and ’70s) as well as periods with deflation (like the Great Depression, 1929–32). But we find similar results over the most recent 30-year period (1991–2020), when U.S. inflation was relatively mild and stable. Over this period, we also expand our analysis to non-USD bonds, developed- and emerging-market equities, real estate investment trusts (REITs), and commodities. Overall, outpacing inflation over the long term has been the rule rather than the exception among the assets we study.

Exhibit 1: Keeping It Real

Average annual real returns in years with above-median U.S. inflation, 1927–2020

Inflation Hedged

Despite the reassuring findings presented above, emphasizing growth assets that have historically outpaced inflation may not be appropriate for everyone. If you’re highly sensitive to inflation and have a low tolerance for market risk, you’ll likely want some exposure to inflation-indexed securities (such as TIPS and inflation swaps), and with good reason: They are designed to provide inflation protection. While stocks from certain industries, REITs, commodities, and value stocks are sometimes considered “inflation-sensitive” assets, the data provide little support that they are good inflation hedges.

Nominal asset prices already embed the market’s expectation of inflation. So inflation concerns are really about the negative impact of unexpected inflation on the real value of your invested wealth. An asset is therefore most useful as an inflation hedge when its nominal returns move closely with unexpected inflation. In the paper, we find mostly weak correlations between nominal returns and unexpected inflation. For the few exceptions where the correlations are reliable, such as for energy stocks and commodities over 1991–2020, the assets’ nominal returns have been around 20 times as volatile as inflation, and more than half of their nominal-return variation has been unrelated to inflation. Exhibit 2 illustrates this by showing how the annual nominal returns to energy stocks and commodities differ dramatically from the annual realizations of inflation. If the goal is to reduce the variability of future purchasing power, it is questionable that hedging with something so volatile will effectively achieve that.

Exhibit 2. One of These Things Isn’t Like the Others

Annual US inflation along with nominal returns to energy stocks and commodities, 1991–2020

Inflation Deflated

What will next month’s inflation reading be? How will it compare to market expectations? Is the rise in inflation temporary or long-lived? Nobody has a crystal ball. Fortunately, we don’t need a crystal ball to address inflation in our portfolios. The data suggest that simply staying invested helps outpace inflation over the long term. And for those of us who are particularly sensitive to unexpected inflation, the protection offered by inflation-indexed securities still appears to be the most effective.