Bitcoin and Stocks Enter September: Could the “September

Curse” Strike Again?

September has historically been one of the weakest months for both Bitcoin and U.S. equities. As September 2026 begins, investors are watching closely to see whether the seasonal pattern returns—or whether markets finally break away from the historical trend.

Bitcoin has historically averaged a 3.3% decline in September since 2013, making it its weakest month of the year. U.S. equities have also struggled during the month, with the S&P 500 recording an average September loss of around 0.6% since 1950 and finishing higher in only about 44% of Septembers.

But history is not destiny. Bitcoin has actually posted positive September returns during each of the past three years, showing that the seasonal pattern can be overturned.

September Has a Reputation for Weak Markets

The so-called “September effect” is one of the most closely watched seasonal patterns in financial markets.

According to historical data cited by Newsbit, September is the only month in which major stock indices have historically produced an average loss.

For the S&P 500:

• Since 1950, only about 44% of Septembers ended with a gain.
• The average September performance has been approximately -0.6%.
• The phenomenon has no single universally accepted explanation.

Bitcoin has an even weaker historical record.

Since 2013, BTC has averaged approximately -3.3% during September, with a median return around -3.12%.

That makes September particularly important for crypto traders.

Why Does the September Effect Exist?

There is no definitive explanation, but several theories have emerged.

1. Investors Return From Vacation

September marks the end of the traditional summer holiday period.

Fund managers and institutional investors return to their desks, rebalance portfolios and reassess risk.

That can increase selling pressure.

2. Tax and Fiscal Considerations

Some investment funds have fiscal year-ends around September or October.

Managers may sell underperforming positions to realize losses or rebalance portfolios.

3. Self-Fulfilling Prophecy

Because investors know September has historically been weak, some become defensive before the month even begins.

That behavior can create additional selling pressure.

In other words:

Everyone expects weakness → investors reduce risk → markets weaken → the historical pattern appears again.

 

Bitcoin Faces a Critical Technical Test

Bitcoin has recently regained momentum, but the recovery still faces important technical obstacles.

According to Newsbit's analysis, BTC remains below its May peak and the 50-week moving average.

A decisive recovery above those levels would provide stronger evidence that the broader trend has turned bullish.

If Bitcoin fails to reclaim them, the market could instead retest its 200-day moving average.

That level could become a crucial support zone.

Could Bitcoin Repeat the 2023 Pattern?

There is an interesting historical comparison.

After the previous crypto winter, Bitcoin in early 2023 first retested its 200-day moving average before eventually breaking through the 50-week average and beginning a much larger bullish trend.

That creates an important scenario for 2026:

BTC holds support

↓

Retests the 200-day average if necessary

↓

Breaks above the 50-week average

↓

Confirms a larger trend reversal

This is not a prediction that the same pattern will repeat, but the historical structure is worth watching.

S&P 500 Enters Consolidation

The stock market is showing a different but related pattern.

The S&P 500 has been consolidating in an upward-sloping range, and according to Newsbit's analysis, this consolidation could potentially continue into early October.

That means the market isn't necessarily displaying outright bearish momentum.

Instead, investors appear to be waiting for a catalyst.

September could therefore become a month of range trading rather than a major correction—unless macroeconomic data changes expectations dramatically.

Nasdaq 100 Forms a Symmetrical Triangle

The Nasdaq 100 is showing even tighter price movement.

The index has formed a symmetrical triangle, with price fluctuations becoming progressively smaller.

Symmetrical triangles are generally considered continuation patterns.

Because the Nasdaq's preceding move was strongly upward, Newsbit notes that the eventual breakout could have a greater probability of occurring to the upside.

However, the breakout direction still needs confirmation.

September's Macro Calendar Is Packed

Seasonality isn't the only thing investors need to watch.

Several major U.S. economic events are scheduled for September.

September 5

U.S. jobs report

Employment data could significantly influence expectations for monetary policy.

September 10–11

U.S. inflation data

Inflation remains one of the Federal Reserve's most important considerations.

September 16

Federal Reserve interest-rate decision

The Fed's decision could become the biggest market-moving event of the month.

 

Rate Expectations Could Decide September

According to the Newsbit report, following a speech by Fed Chair Kevin Warsh, approximately 66% of the market expected a rate hike at the following month's meeting.

However, weaker employment data or lower inflation could reduce those expectations.

This creates an interesting setup.

Bad economic data could be bullish

If weaker employment and lower inflation convince investors that monetary policy can become less restrictive, risk assets such as Bitcoin and stocks could benefit.

Bad economic data could also be bearish

If investors interpret weak economic data as evidence of a broader economic slowdown, risk appetite could decline.

The market reaction will therefore depend on how the data changes Fed expectations, rather than simply whether the numbers are good or bad.

Bond Yields Remain a Major Risk

Long-term U.S. Treasury yields are another important variable.

Concerns about:

• The U.S. debt burden
• The federal deficit
• Large-scale AI investment
• Government borrowing

have contributed to elevated long-term borrowing costs.

High long-term yields can put pressure on a wide range of assets.

The transmission mechanism is straightforward:

Higher Treasury yields

→ higher borrowing costs

→ more expensive mortgages and corporate loans

→ tighter financial conditions

→ pressure on stocks and Bitcoin

This makes the bond market an important signal for both traditional and crypto investors.

Iran-US Conflict Adds Another Variable

The geopolitical situation involving the United States and Iran could also influence markets throughout September.

The key variable is oil.

A significant increase in oil prices could push inflation higher.

Higher inflation could then affect central-bank policy expectations.

That creates a chain reaction:

Geopolitical escalation

↓

Oil prices rise

↓

Inflation expectations increase

↓

Fed policy becomes more restrictive

↓

Risk assets face pressure

Bitcoin, stocks and precious metals could all respond to this dynamic.

 

Why September Could Still Be Bullish

The historical September effect should not be treated as a guaranteed market forecast.

Bitcoin itself provides the strongest counterexample.

Despite its poor long-term September statistics, BTC has posted positive returns during the last three Septembers.

Meanwhile, the Nasdaq 100's technical structure could eventually favor an upside breakout if the broader bullish trend continues.

A bullish September scenario could therefore involve:

• Lower-than-expected inflation
• Weaker employment data
• Reduced rate-hike expectations
• Falling Treasury yields
• Stable oil prices
• Continued institutional demand
• Bitcoin reclaiming its major moving averages
• Nasdaq breaking higher from its triangle

Why September Could Turn Ugly

The opposite scenario would involve:

Higher Inflation

Markets could price in tighter monetary policy.

Strong Employment Data

A strong labor market could give the Fed more room to maintain or raise rates.

Rising Treasury Yields

Higher long-term yields could tighten financial conditions.

Higher Oil Prices

Geopolitical tensions could push inflation expectations higher.

Failed Bitcoin Breakout

Failure to reclaim the 50-week moving average could leave BTC vulnerable to another decline.

Seasonal Selling

If investors begin positioning defensively because of the September effect, the historical pattern could reinforce itself.

September 2026 Market Checklist

Market Driver	Potential Impact
BTC 50-week average	Key trend confirmation
BTC 200-day average	Potential support
S&P 500	Consolidation / breakout
Nasdaq 100	Symmetrical triangle
Sept. 5 jobs report	Fed expectations
Sept. 10–11 CPI data	Inflation expectations
Sept. 16 Fed decision	Major market catalyst
Treasury yields	Financial-condition signal
Oil prices	Inflation/geopolitical risk
Iran-US conflict	Potential volatility

 

Bitcoin vs. Stocks: Will They Move Together?

One of the most interesting questions for September is whether Bitcoin and equities will continue behaving as correlated risk assets.

When liquidity conditions are favorable, both can benefit from:

Lower yields + stronger liquidity + higher risk appetite

But during periods of financial stress, Bitcoin's higher volatility can cause it to fall more aggressively than traditional equities.

That means September could provide another test of Bitcoin's evolving relationship with the broader financial system.

What Investors Should Watch

The most important indicators during September will be:

Bitcoin

Can BTC reclaim the 50-week moving average and May peak?

200-Day Moving Average

Does Bitcoin hold this level if the rally fails?

S&P 500

Does consolidation resolve higher or lower?

Nasdaq 100

Which direction does the symmetrical triangle break?

???????? Inflation

Does CPI strengthen or weaken the case for tighter monetary policy?

Jobs

Does the labor market remain strong?

Federal Reserve

Will rate expectations shift?

Treasury Yields

Can long-term yields finally move lower?

Oil

Does geopolitical risk push energy prices higher?

Final Take

September begins with a warning from history.

For stocks, the month has historically been the weakest period of the year, with the S&P 500 averaging around -0.6% since 1950 and finishing higher in only about 44% of Septembers. Bitcoin's record is even weaker, with an average September return of approximately -3.3% since 2013.

But investors should not assume that history will automatically repeat.

Bitcoin has actually finished the last three Septembers in positive territory, while the Nasdaq 100's current technical structure could eventually favor an upside breakout.

The bigger story this year will likely be macroeconomic.

Jobs data, inflation, the Federal Reserve, Treasury yields, oil prices and geopolitical tensions could matter far more than seasonality alone.

For Bitcoin, the key technical question is whether it can reclaim its 50-week moving average and previous May peak. If not, a retest of the 200-day moving average remains a possibility.

So, will the September curse strike again?

History says investors should be cautious—but 2026 may once again prove that seasonal trends are tendencies, not guarantees.