BFM Bentley Financial Management

Market Perspective

A century of the market, month by month

The BFM Investment Team · July 9, 2026

Two of the questions we hear most often are versions of the same worry: “Is now a good time to invest?” and “Should we wait until after the election?” Rather than answer with a slogan, we built the answer from the record.

Below is every month of U.S. stock market returns for the last one hundred years — 1,199 months, July 1926 through May 2026, covering every U.S.-listed stock with dividends reinvested — along with every quarter and every full year, and the crashes, wars, and elections marked where they happened. Explore it; every cell answers to a hover. Then read what we take from it at the bottom.

$1 → $19,374
Growth of one dollar, July 1926 – May 2026, dividends reinvested. That is 10.4% a year, compounded.
63%
Of all 1,199 months were positive. The average month gained just under 1%.
75 of 99
Full calendar years finished higher. The worst was 1931, down 43.8%; the best was 1933, up 56.8%.
+38.9 / −28.7
The best month (April 1933) and the worst (September 1931) came within two years of each other, in the Depression.

What one dollar became

The chart uses a ratio scale: each step up the left side is a tenfold gain, so equal moves mean equal percentage changes. Every crisis on this line felt like the end of the world at the time. At this distance, most are hard to find. Hover to see any month.

The hundred-year board

Each cell is one month’s return — blue for gains, red for losses, deeper color for bigger moves. The quarter columns shade on a wider scale (to ±25%) and the year column wider still (to ±45%), so their colors are not directly comparable to the months. Hover any cell for the exact figure.

Monthly scale:−12%
+12% presidential election year

The monthly pattern

Average return by calendar month, with how often that month finished higher. September is the only month that loses money on average — and the only coin flip. November and December have historically been the most consistent. But keep the noise in view: a typical month swings 4–6 percentage points around these small averages.

The quarterly pattern

The fourth quarter is the standout — higher in 81 of the last 100 years, with the best average of the four. The third quarter has to carry September, and it shows.

The presidential cycle

Average full-year return by year of the presidential term. The year before an election has finished higher 24 times out of 25 — the single loss was 1931, in the middle of the Depression. Midterm years have been the softest.

How election years actually unfold

The average path of $100 through the year. Election years run behind through spring, catch up by late summer, go flat in the two months before the vote — then finish with a strong November and December once the result is known, whichever party wins.

Election years (25) All years (100)

Sectors under five presidencies

Average yearly return of each S&P 500 sector over each presidency, ranked best to worst. The colors follow the rest of this page — blue for gains, red for losses. Hover any sector to follow it from one administration to the next.

1

Same winners, different parties. The three best sectors under Obama were the same three best under the first Trump term — and two of the three worst matched, too.

2

Technology has been a top-three sector in four straight presidencies. In the term before those four, under Bush, it was the single worst.

3

Energy was the best sector under both Biden and Bush — and the worst under the first Trump term. The campaign trail is not the trading floor.

Sector data: BlackRock, “Student of the Market,” from S&P 500 sector returns by presidential term. Real estate became its own sector in 2016 and communication services was redefined in 2018; earlier terms follow the source’s mapping. The Trump 2 figures are annualized from a term still in progress and will change.

So is the calendar a signal?

Mostly no — and usefully yes, in a few narrow places. The monthly averages are small, about 1%, while the normal swing in any given month is four to six times larger. No single month is dependable. What does hold up across a century: September is the only month that has lost money on average, November and December have historically been the most consistent, and the fourth quarter has finished higher in 81 of the last 100 years.

The steadiest pattern is not seasonal at all — it is the presidential cycle. The year before an election has finished higher 24 times out of 25. Election years themselves end up about average; what changes is the shape. Markets hesitate in the two months before the vote, then tend to finish strong once the uncertainty clears, no matter who wins. Waiting “until after the election” has historically meant paying more, not less.

Just as important is what the calendar never did: it never saw a crash coming. Black Monday came in October 1987, the financial crisis broke in September 2008, and COVID hit in February 2020 — three different months, and the seasonal averages flagged none of them in advance. And 2008 was an election year in which the market lost more than a third of its value. The label protected no one.

Keep politics out of your portfolio

The sector table above is the strongest argument we know for separating how you vote from how you invest. The best-performing sector of the Biden years was energy — up 38% a year under a president who campaigned against fossil fuels. The worst sector of the first Trump term was also energy — down 16% a year under a president who promised to unleash it. Technology led under both parties. Markets follow earnings, interest rates, and innovation far more faithfully than they follow the party in power.

Our partners at BlackRock put it in a rule we like: KPOP — keep politics out of portfolios. Politics matter enormously in your life, your community, and your tax planning. Inside a portfolio, a century of evidence says they matter far less than the news would have you believe. The election-year chart above tells the same story: markets have rewarded the investor who stayed put through the vote, whichever way it went.

What this means for how we invest

We treat patterns like these as context, not commands. They can shade the timing of an addition or a trim at the margin. They are never, on their own, a reason to buy or to sell. The most important line on this page is the first one: through a depression, a world war, years of double-digit inflation, and four major crashes, one dollar became $19,374 — but only for the investor who stayed. That is the signal.

Source: monthly returns for the entire U.S. stock market — every U.S.-listed common stock, weighted by company size, with dividends reinvested — from the Center for Research in Security Prices (CRSP), via the Kenneth R. French Data Library. Quarterly and annual figures are compounded from the monthly series; 1926 begins in July and 2026 runs through May. “Up” percentages show how often that period finished positive. For informational purposes only; not investment advice or a recommendation to buy or sell any security. Past performance is not indicative of future results.

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