Inflation, Deflation, and Stock Market Returns

Inflation! Deflation!

Two words that strike fear into the hearts of investors.

Are such fears justified? Let’s take a look…

If we segment calendar year changes in the Consumer Price Index (CPI) into quintiles, we observe the following:

  • The lowest equity returns have occurred in deflationary (quintile 1) and inflationary (quintile 5) environments.
  • The highest equity returns have occurred in periods of low (quintile 2 & 3) to moderate (quintile 4) inflation.

Image of S&P 500 annualized total returns at various inflation levels from 1928 to 2017

Source Data for all tables herein: YCharts, BLS,

During years with the highest inflation (quintile 5):

  • Stocks generated the lowest nominal returns, 4% on average, with 56% of years posting a positive return. The real equity returns, at -3.5%, were also the lowest.
  • Many of the years represented in this quintile occurred during the 1970s (1970, 1973, 1974, 1975, 1976, 1977, 1978, and 1979) early 1980s (1980, 1981). Stagflation was the great concern of this period.
  • Many of the worst stock market returns in this quintile occurred during years in which the economy was in recession (1969, 1973-74, 1981, 1990).

Inflation Quintile 5 list from 1928 to 2017

During years with the lowest inflation (quintile 1):

  • Stocks generated an annualized return of 4.6% with 56% of years posting a positive return. The real equity returns, at 6.5%, were higher than the nominal returns due to the negative annualized CPI in this quintile.
  • Many of the years represented were during the Great Depression (1929-1932) and the subsequent decade (1938, 1939, 1940). Deflation was the great concern during this period.
  • Many of the worst stock market returns in this quintile occurred during years in which the economy was in recession (1929-1932, 1953, and 2008).

Inflation Quintile 1 list from 1928 to 2017

What’s left? The so-called “goldilocks” periods in which inflation was running neither too cold nor too hot (in a range between 1.2% and 4.7%). It was during these quintiles that stocks posted their best returns on both a nominal and real basis.

Inflation Quintile lists from 1928 to 2017

The “goldilocks” periods (quintiles 2-4) also contained fewer recessions and consequently a higher percentage of years in which stocks finished higher.

Image of various inflation levels of stocks from 1928 to 2017

Which quintile are we in today?

With the CPI up 2.1% over the past year, we are right on the border of quintile 2 and quintile 3. While fears of inflation seem to be picking up in recent weeks, we’re still much closer to a deflationary environment than an inflationary one. And things can change rather quickly: CPI was 4.1% in 2007 before the 2008 deflationary collapse.

Image of US CPI and rolling historical median from 1948 to 2018

Source Data: St. Louis Fed (FRED).

The Federal Reserve seems to be of this opinion as well, with the Effective Fed Funds Rate of 1.42% still below inflation and far below its historical average of 4.86%.

Effective Fed Funds Rate from 1954 to 2018 image

Source Data: St. Louis Fed (FRED).

Does that mean stocks can’t go down as long as inflation stays where it is?

No. While the “goldilocks” quintiles have historically shown higher returns and more positive years than inflationary/deflationary regimes, there are a number of exceptions. Most recently, stocks declined in 2000 (-9.2%), 2001 (-11.9%), and 2002 (22.1%) with CPI registering 3.4%, 1.6%, and 2.5% during those years. With the exact same inflation numbers in 1995 (2.5%), 1996 (3.4%), and 1998 (1.6%) stocks finished higher by 37.6%, 23%, and 28.6%.

Which should tell you that the level of inflation is only one of many factors influencing equity returns. Much more important to short-term returns is sentiment (how much investors are willing to pay for a given level of earnings) and to long-term returns is valuation (how much investors are paying today relative to history).

Even if you were able to predict the level of inflation next year with precision, it would be impossible to use that figure in predicting the return of the stock market.

Inflation! Deflation!

Perhaps there are more important things for investors to worry about.




Charlie Bilello is the Director of Research at Pension Partners, LLC, an investment advisor that manages mutual funds and separate accounts. He is the co-author of four award-winning research papers on market anomalies and investing. Mr. Bilello is responsible for strategy development, investment research and communicating the firm’s investment themes and portfolio positioning to clients. Prior to joining Pension Partners, he was the Managing Member of Momentum Global Advisors and previously held positions as a Credit, Equity and Hedge Fund Analyst at billion dollar alternative investment firms.

Mr. Bilello holds a J.D. and M.B.A. in Finance and Accounting from Fordham University and a B.A. in Economics from Binghamton University. Charlie holds a J.D. and M.B.A. in Finance and Accounting from Fordham University and a B.A. in Economics from Binghamton University. He is a Chartered Market Technician (CMT) and also holds the Certified Public Accountant (CPA) certificate.

In 2017, Charlie was named the StockTwits Person of the Year. He is a frequent contributor to Yahoo Finance and has been interviewed on CNBC, Bloomberg, and Fox Business.

You can follow Charlie on twitter here.


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The Standard & Poor’s 500, often abbreviated as the S&P 500, or just the S&P, is an American stock market index based on the market capitalizations of 500 large companies having common stock listed on the NYSE or NASDAQ.


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