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Market statistics

S&P 500 returns by month, 1928 to today

September loses more than a percent in the average year — no other month loses even a tenth of that — and December wins most often. Whether that is a pattern or ninety-eight coin flips arranged into twelve buckets is the question the page is really about.

98 years per month · data through 28 Aug 2026

19282025

Strongest month
July
+1.69% average
Weakest month
September
-1.13% average
Most reliable
December
up 72.4% of years
Months averaging negative
2 of 12
Feb, Sep

Average return by month

  • January+1.21%
  • February-0.10%
  • March+0.48%
  • April+1.26%
  • May+0.08%
  • June+0.80%
  • July+1.69%
  • August+0.68%
  • September-1.13%
  • October+0.56%
  • November+1.01%
  • December+1.27%

Share of years the month finished positive

  • January62%
  • February52%
  • March61%
  • April65%
  • May60%
  • June57%
  • July61%
  • August58%
  • September45%
  • October59%
  • November62%
  • December72%
Every month, aggregated over full years. The compound column is what a portfolio invested only in that month of every year would have earned per holding.
MonthAverageMedianCompoundPositiveBestWorst
January+1.21%+1.56%+1.10%62.2%+13.2%-8.6%
February-0.10%+0.27%-0.19%52.0%+11.4%-18.4%
March+0.48%+1.11%+0.34%61.2%+11.7%-25.0%
April+1.26%+0.94%+1.09%65.3%+33.9%-20.3%
May+0.08%+1.07%-0.10%60.2%+23.1%-24.0%
June+0.80%+0.48%+0.68%57.1%+24.7%-16.5%
July+1.69%+1.76%+1.54%61.2%+36.1%-11.5%
August+0.68%+0.88%+0.52%58.2%+39.1%-14.6%
September-1.13%-0.35%-1.31%44.9%+14.4%-29.9%
October+0.56%+1.18%+0.37%59.2%+16.3%-21.8%
November+1.01%+1.65%+0.88%62.2%+12.0%-13.4%
December+1.27%+1.49%+1.20%72.4%+11.2%-14.5%
Every month of every year, newest first. Blank cells are months the published history does not reach.
YearJanFebMarAprMayJunJulAugSepOctNovDec
2026+1.4%-0.9%-5.1%+10.4%+5.2%-1.1%-0.1%+3.0%
2025+2.7%-1.4%-5.8%-0.8%+6.2%+5.0%+2.2%+1.9%+3.5%+2.3%+0.1%-0.1%
2024+1.6%+5.2%+3.1%-4.2%+4.8%+3.5%+1.1%+2.3%+2.0%-1.0%+5.7%-2.5%
2023+6.2%-2.6%+3.5%+1.5%+0.3%+6.5%+3.1%-1.8%-4.9%-2.2%+8.9%+4.4%
2022-5.3%-3.1%+3.6%-8.8%0.0%-8.4%+9.1%-4.2%-9.3%+8.0%+5.4%-5.9%
2021-1.1%+2.6%+4.2%+5.2%+0.6%+2.2%+2.3%+2.9%-4.8%+6.9%-0.8%+4.4%
2020-0.2%-8.4%-12.5%+12.7%+4.5%+1.8%+5.5%+7.0%-3.9%-2.8%+10.8%+3.7%
2019+7.9%+3.0%+1.8%+3.9%-6.6%+6.9%+1.3%-1.8%+1.7%+2.0%+3.4%+2.9%
2018+5.6%-3.9%-2.7%+0.3%+2.2%+0.5%+3.6%+3.0%+0.4%-6.9%+1.8%-9.2%
2017+1.8%+3.7%0.0%+0.9%+1.2%+0.5%+1.9%+0.1%+1.9%+2.2%+2.8%+1.0%
2016-5.1%-0.4%+6.6%+0.3%+1.5%+0.1%+3.6%-0.1%-0.1%-1.9%+3.4%+1.8%
2015-3.1%+5.5%-1.7%+0.9%+1.1%-2.1%+2.0%-6.3%-2.6%+8.3%+0.1%-1.8%
2014-3.6%+4.3%+0.7%+0.6%+2.1%+1.9%-1.5%+3.8%-1.6%+2.3%+2.5%-0.4%
2013+5.0%+1.1%+3.6%+1.8%+2.1%-1.5%+5.0%-3.1%+3.0%+4.5%+2.8%+2.4%
2012+4.4%+4.1%+3.1%-0.8%-6.3%+4.0%+1.3%+2.0%+2.4%-2.0%+0.3%+0.7%
2011+2.3%+3.2%-0.1%+2.9%-1.4%-1.8%-2.2%-5.7%-7.2%+10.8%-0.5%+0.9%
2010-3.7%+2.9%+5.9%+1.5%-8.2%-5.4%+6.9%-4.7%+8.8%+3.7%-0.2%+6.5%
2009-8.6%-11.0%+8.5%+9.4%+5.3%0.0%+7.4%+3.4%+3.6%-2.0%+5.7%+1.8%
2008-6.1%-3.5%-0.6%+4.8%+1.1%-8.6%-1.0%+1.2%-9.1%-16.9%-7.5%+0.8%
2007+1.4%-2.2%+1.0%+4.3%+3.3%-1.8%-3.2%+1.3%+3.6%+1.5%-4.4%-0.9%
2006+2.6%+0.1%+1.1%+1.2%-3.1%0.0%+0.5%+2.1%+2.5%+3.2%+1.7%+1.3%
2005-2.5%+1.9%-1.9%-2.0%+3.0%0.0%+3.6%-1.1%+0.7%-1.8%+3.5%-0.1%
2004+1.7%+1.2%-1.6%-1.7%+1.2%+1.8%-3.4%+0.2%+0.9%+1.4%+3.9%+3.3%
2003-2.7%-1.7%+0.8%+8.1%+5.1%+1.1%+1.6%+1.8%-1.2%+5.5%+0.7%+5.1%
2002-1.6%-2.1%+3.7%-6.1%-0.9%-7.3%-7.9%+0.5%-11.0%+8.6%+5.7%-6.0%
2001+3.5%-9.2%-6.4%+7.7%+0.5%-2.5%-1.1%-6.4%-8.2%+1.8%+7.5%+0.8%
2000-5.1%-2.0%+9.7%-3.1%-2.2%+2.4%-1.6%+6.1%-5.4%-0.5%-8.0%+0.4%
1999+4.1%-3.2%+3.9%+3.8%-2.5%+5.4%-3.2%-0.6%-2.9%+6.3%+1.9%+5.8%
1998+1.0%+7.0%+5.0%+0.9%-1.9%+3.9%-1.2%-14.6%+6.2%+8.0%+5.9%+5.6%
1997+6.1%+0.6%-4.3%+5.8%+5.9%+4.4%+7.8%-5.8%+5.3%-3.5%+4.5%+1.6%
1996+3.3%+0.7%+0.8%+1.3%+2.3%+0.2%-4.6%+1.9%+5.4%+2.6%+7.3%-2.2%
1995+2.4%+3.6%+2.7%+2.8%+3.6%+2.1%+3.2%0.0%+4.0%-0.5%+4.1%+1.7%
1994+3.3%-3.0%-4.6%+1.2%+1.2%-2.7%+3.2%+3.8%-2.7%+2.1%-4.0%+1.2%
1993+0.7%+1.1%+1.9%-2.5%+2.3%+0.1%-0.5%+3.4%-1.0%+1.9%-1.3%+1.0%
1992-2.0%+1.0%-2.2%+2.8%+0.1%-1.7%+3.9%-2.4%+0.9%+0.2%+3.0%+1.0%
1991+4.2%+6.7%+2.2%0.0%+3.9%-4.8%+4.5%+2.0%-1.9%+1.2%-4.4%+11.2%
1990-6.9%+0.9%+2.4%-2.7%+9.2%-0.9%-0.5%-9.4%-5.1%-0.7%+6.0%+2.5%
1989+7.1%-2.9%+2.1%+5.0%+3.5%-0.8%+8.8%+1.6%-0.7%-2.5%+1.7%+2.1%
1988+4.0%+4.2%-3.3%+0.9%+0.3%+4.3%-0.5%-3.9%+4.0%+2.6%-1.9%+1.5%
1987+13.2%+3.7%+2.6%-1.2%+0.6%+4.8%+4.8%+3.5%-2.4%-21.8%-8.5%+7.3%
1986+0.2%+7.2%+5.3%-1.4%+5.0%+1.4%-5.9%+7.1%-8.5%+5.5%+2.2%-2.8%
1985+7.4%+0.9%-0.3%-0.5%+5.4%+1.2%-0.5%-1.2%-3.5%+4.3%+6.5%+4.5%
1984-0.9%-3.9%+1.4%+0.6%-5.9%+1.8%-1.7%+10.6%-0.4%0.0%-1.5%+2.2%
1983+3.3%+1.9%+3.3%+7.5%-1.2%+3.2%-3.0%+1.1%+1.0%-1.5%+1.7%-0.9%
1982-1.8%-6.1%-1.0%+4.0%-3.9%-2.0%-2.3%+11.6%+0.8%+11.0%+3.6%+1.5%
1981-4.6%+1.3%+3.6%-2.4%-0.2%-1.0%-0.2%-6.2%-5.4%+4.9%+3.7%-3.0%
1980+5.8%-0.4%-10.2%+4.1%+4.7%+2.7%+6.5%+0.6%+2.5%+1.6%+10.2%-3.4%
1979+4.0%-3.7%+5.5%+0.2%-2.6%+3.9%+0.9%+5.3%0.0%-6.9%+4.3%+1.7%
1978-6.2%-2.5%+2.5%+8.5%+0.4%-1.8%+5.4%+2.6%-0.7%-9.2%+1.7%+1.5%
1977-5.1%-2.2%-1.4%0.0%-2.4%+4.5%-1.6%-2.1%-0.3%-4.3%+2.7%+0.3%
1976+11.8%-1.1%+3.1%-1.1%-1.4%+4.1%-0.8%-0.5%+2.3%-2.2%-0.8%+5.3%
1975+12.3%+6.0%+2.2%+4.7%+4.4%+4.4%-6.8%-2.1%-3.5%+6.2%+2.5%-1.2%
1974-1.0%-0.4%-2.3%-3.9%-3.4%-1.5%-7.8%-9.0%-11.9%+16.3%-5.3%-2.0%
1973-1.7%-3.8%-0.1%-4.1%-1.9%-0.7%+3.8%-3.7%+4.0%-0.1%-11.4%+1.7%
1972+1.8%+2.5%+0.6%+0.4%+1.7%-2.2%+0.2%+3.5%-0.5%+0.9%+4.6%+1.2%
1971+4.1%+0.9%+3.7%+3.6%-4.2%-0.9%-3.2%+3.6%-0.7%-4.2%-0.3%+8.6%
1970-7.7%+5.3%+0.2%-9.1%-6.1%-5.0%+7.3%+4.5%+3.4%-1.3%+4.7%+5.7%
1969-0.8%-4.7%+3.4%+2.2%-0.2%-5.6%-6.0%+4.0%-2.5%+4.3%-3.4%-1.9%
1968-4.4%-3.1%+0.9%+8.1%+1.3%+0.9%-1.9%+1.2%+3.9%+0.7%+4.8%-4.2%
1967+7.8%+0.2%+3.9%+4.2%-5.2%+1.8%+4.5%-1.2%+3.3%-3.5%+0.8%+2.6%
1966+0.5%-1.8%-2.2%+2.1%-5.4%-1.6%-1.4%-7.8%-0.7%+4.8%+0.3%-0.2%
1965+3.3%-0.2%-1.5%+3.4%-0.8%-4.9%+1.3%+2.3%+3.2%+2.7%-0.9%+0.9%
1964+2.7%+1.0%+1.5%+0.6%+1.2%+1.6%+1.8%-1.6%+2.9%+0.8%-0.5%+0.4%
1963+4.9%-2.9%+3.6%+4.9%+1.4%-2.0%-0.4%+4.9%-1.1%+3.2%-1.1%+2.4%
1962-3.8%+1.6%-0.6%-6.2%-8.6%-8.2%+6.4%+1.5%-4.8%+0.4%+10.2%+1.4%
1961+6.3%+2.7%+2.6%+0.4%+1.9%-2.9%+3.3%+2.0%-2.0%+2.8%+3.9%+0.3%
1960-7.2%+0.9%-1.4%-1.8%+2.7%+2.0%-2.5%+2.6%-6.0%-0.2%+4.0%+4.6%
1959+0.4%-0.1%+0.1%+3.9%+1.9%-0.4%+3.5%-1.5%-4.6%+1.1%+1.3%+2.8%
1958+4.3%-2.1%+3.1%+3.2%+1.5%+2.6%+4.3%+1.2%+4.8%+2.5%+2.2%+5.2%
1957-4.2%-3.3%+2.0%+3.7%+3.7%-0.1%+1.1%-5.6%-6.2%-3.2%+1.6%-4.2%
1956-3.7%+3.5%+6.9%-0.2%-6.6%+3.9%+5.2%-3.8%-5.9%+2.0%-1.1%+3.5%
1955+1.8%+0.4%-0.5%+3.8%-0.1%+8.2%+6.1%-0.8%+1.1%-3.1%+7.5%-0.1%
1954+5.1%+0.3%+3.0%+4.9%+3.3%+0.1%+5.7%-3.4%+8.3%-2.0%+8.1%+5.1%
1953-0.7%-1.8%-2.4%-2.7%-0.3%-1.6%+2.5%-5.8%+0.1%+5.1%+0.9%+0.2%
1952+1.6%-3.7%+4.8%-4.3%+2.3%+4.6%+1.8%-1.5%-2.0%-0.1%+4.7%+3.6%
1951+6.0%+0.7%-1.5%+4.4%-4.1%-2.6%+6.9%+3.9%-0.1%-1.4%-0.3%+3.9%
1950+1.6%+1.0%+0.4%+3.9%+4.6%-5.8%+0.9%+3.3%+5.6%+0.4%-0.1%+4.7%
1949+0.1%-3.9%+3.0%-2.3%-3.5%-0.2%+6.2%+1.2%+2.4%+3.0%+0.1%+4.6%
1948-4.1%-5.1%+8.3%+2.7%+7.8%+0.3%-5.3%+0.8%-3.0%+6.5%-10.6%+3.1%
1947+2.4%-1.5%-1.7%-3.9%-0.9%+5.3%+3.6%-2.8%-1.4%+2.1%-2.9%+2.1%
1946+7.0%-7.0%+4.4%+4.0%+2.2%-3.9%-2.6%-7.3%-10.2%-0.8%-1.1%+4.2%
1945+1.4%+6.2%-4.8%+9.0%+1.2%-0.9%-1.4%+5.8%+3.5%+3.7%+3.2%+1.0%
1944+1.5%-0.3%+1.7%-1.3%+4.0%+5.1%-2.1%+0.9%-0.6%+0.3%+0.4%+3.5%
1943+6.9%+5.1%+5.6%+0.1%+4.0%+2.5%-4.1%-0.4%+2.4%-1.4%-7.5%+5.9%
1942+1.8%-2.9%-6.8%-4.4%+6.4%+1.8%+3.1%+0.7%+2.7%+5.8%-0.8%+5.2%
1941-4.8%-1.5%+0.4%-6.5%+0.8%+5.0%+5.5%-1.1%-0.8%-6.9%-4.0%-4.7%
1940-3.3%+0.7%+0.4%+0.1%-24.0%+7.7%+3.1%+2.0%+1.5%+3.9%-4.6%+0.1%
1939-6.4%+3.3%-13.5%-0.5%+6.1%-6.4%+10.9%-7.1%+14.4%+0.3%-4.9%+2.1%
1938+1.3%+6.1%-25.0%+15.1%-5.2%+24.7%+6.7%-2.2%+1.5%+7.6%-3.3%+3.2%
1937+3.4%+1.6%-0.8%-8.3%-1.0%-5.3%+8.9%-4.4%-14.2%-10.3%-10.0%-5.0%
1936+6.6%+2.0%+2.2%-7.7%+4.6%+3.1%+6.8%+0.9%+0.1%+7.6%+0.3%-0.6%
1935-4.2%-4.0%-3.3%+9.8%+3.2%+6.9%+8.2%+1.4%+3.1%+7.5%+3.9%+3.8%
1934+12.0%-3.7%-1.3%-1.5%-8.1%+2.1%-11.5%+5.4%-0.8%-3.0%+8.3%-0.4%
1933+0.3%-18.4%+3.4%+33.9%+23.1%+13.2%-8.8%+11.5%-12.4%-7.8%+10.3%+0.9%
1932-2.2%+4.4%-11.8%-20.3%-23.3%-0.9%+36.1%+39.1%-3.7%-13.9%-5.9%+5.7%
1931+5.5%+11.4%-7.4%-9.6%-13.7%+13.9%-7.4%+1.0%-29.9%+7.4%-8.9%-14.5%
1930+6.3%+2.2%+3.7%+3.1%-1.7%-16.5%+3.7%+0.8%-13.0%-8.9%-3.3%-6.4%
1929+5.7%-0.6%-0.2%+1.6%-4.3%+10.4%+5.4%+9.8%-4.9%-19.9%-13.4%+2.5%
1928-0.5%-1.8%+11.7%+2.4%+1.3%-4.3%+1.5%+7.4%+1.3%+2.6%+12.0%+0.3%

Price returns from daily closing levels. Index price returns exclude dividends. Full provenance, method and a citation line are in Sources and method below.

Is any of this a pattern?

September is the weakest month in the whole record, at -1.13%, and it finishes positive in only 45% of years — one of only two months whose long-run average is negative (February and September), and by a distance the worst of them. December finishes up most often, in 72%. Those are the two facts this table is quoted for, and both are correctly computed from ninety-eight years of closes.

Now the harder question. Each month has about ninety-eight observations, which sounds like a lot and is not: with twelve buckets and that much noise, one of them being the worst is guaranteed, and the interesting question is whether it is the same one for a reason. No mechanism has ever been established for September. The effect has been documented in the literature for decades, which means anyone who could trade it profitably has had a very long time to do so — and an anomaly that survives being published is unusual.

The matrix underneath is the honest way to check. Read down the September column and you will find the 1930s, 2001, 2002 and 2008 doing most of the work, with plenty of ordinary Septembers in between. A handful of catastrophes in one bucket is a different claim from a persistent monthly tendency, and only the full column can tell you which you are looking at.

Where seasonality is genuinely useful is as a check on your own reasoning. If you find yourself explaining a quiet September as evidence of something, the table is a reminder that most Septembers are unremarkable and the average is being carried by a few that were not.

Questions people ask about this

Is the September effect real?
It is real in this dataset: September has the lowest average calendar return of any month by a wide margin and finishes positive less often than any other. Whether it is predictive is a different question. Ninety-eight observations per month is not many, no mechanism has ever been established, and the effect is well known enough that anyone who could trade it already has.
Does 'sell in May and go away' show up here?
Partly. The May-to-October half of the year has been weaker than November-to-April in this record, but the gap is driven mostly by September, and July is one of the stronger months in the whole table. The saying compresses a lumpy six-month pattern into a rhyme.
Why does the average month differ from the median?
Because a handful of extreme months pull the average around. The median is what a typical month in that bucket looked like; the average includes 1931's collapses and 1933's rebounds. Where the two disagree sharply — as they do in May — the month's history is more uneven than a single figure can carry.

Sources and method

Data
  • Financial Modeling PrepDaily adjusted closing levels and quotes, retrieved through Plutux's own data service.
  • S&P Dow Jones IndicesPublisher and methodology owner of the S&P 500 index itself.
How it was calculated
Each month's return is the last close of that month against the last close of the prior month, computed from the full daily series. A month is skipped if the preceding month is missing from the history, so no figure spans a gap. The compound column is the geometric average of that month across every year. Aggregates use full years only; the current year appears in the table but not in the summary. Price returns, dividends excluded.
How often it changes
Regenerated from the full daily history about once a year; the date it runs through is at the top of the page.
Citing this page

Free to quote — please link rather than copy the table.

Plutux. "S&P 500 returns by month, 1928 to today." Data through 28 Aug 2026. https://plutux.ai/resources/tools/sp-500-monthly-returns

Historical figures for information only — not investment advice, and not a forecast.

Plutux is not an investment adviser. Market data and AI-generated analysis are for information and education only, not investment advice. Disclaimer

© Plutux Technology Limited 2026
S&P 500 Monthly Returns and Seasonality (1928-Present) | Plutux