For more than a decade, September has been the worst month for crypto. Bitcoin has posted a median September return of –3.1% since 2013, while Ethereum’s is even weaker at –12.7%. Historic collapses — like Bitcoin’s –19% drop in 2014 or Ethereum’s –21% fall in 2017 — gave rise to the phrase “crypto September blues.”
Last year broke the pattern slightly. Bitcoin gained 7.1% and Ethereum rose 3.2% in September 2024, helped by the launch of ETFs and a 50-basis-point rate cut. That showed the “curse” could bend under new drivers. Now in 2025, with both assets near all-time highs and multiple structural supports in play, the key question is whether this crypto September finally breaks the pattern.
A Look Back: Why September Is the Weakest Month
The poor reputation of September rests on three foundations: market structure, macro cycles, and sentiment.
Historically, exchange reserves were high, meaning plenty of supply ready to sell. At the same time, profit supply was low — not enough holders in profit to entice others, making panic selling easier.
The macro backdrop often added fuel. Following 2021, the COVID aftershocks and tightening liquidity led to September being the month when rallies stalled.
The drawdowns were brutal:
- 2014: Bitcoin –19%
- 2015: Ethereum –45% in its worst September.
- 2019: Bitcoin –14%, Ethereum, a minor 3.95% gain
- 2022: BTC and ETH shed 3.10% and 14.6% respectively (tightening crushed risk assets)
Even when cycles were strong, crypto September had a way of cutting into momentum.
On September 1, 2025, Bitcoin’s dominance was 58.45% and Ethereum’s 14%, almost unchanged from early Sept 2024. Together, they still command >72% of crypto, so their moves set the tone for this crypto September.
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Why September 2025 Feels Different
This year, the setup has shifted. Exchange supply is leaner, ETFs are structural buyers, stablecoin reserves are at record highs, and derivatives positioning could fuel short squeezes.
Exchange Reserves Are Down
Supply on exchanges has thinned compared with last year:
- Bitcoin: down from about 3.0 million BTC (September 4, 2024) to 2.4 million BTC now.
- Ethereum: down from 19.3 million ETH to 17.3 million ETH.
Unlike past September, there is less coin sitting on exchanges ready to sell.
And guess what, September accumulation, led by the whales, seems to have started already:
ETFs Are a Structural Force
Spot ETFs now anchor demand:
- Bitcoin ETFs: lifetime inflows $54.58 billion, already +$332.76 million in September.
- Ethereum ETFs: lifetime inflows $13.49 billion.
ETFs act as a structural absorber of selling pressure, something that simply didn’t exist in earlier cycles, at least not this aggressively. Early September flows look cautious, with positioning likely tethered to the upcoming Fed decision.
Stablecoin Reserves Provide Dry Powder
Stablecoin balances — the dry powder for re-entry — have nearly doubled:
- September 4, 2024: $28.4 billion.
- September 4, 2025: $54.9 billion.
This cushion means capital is already on-chain if there are price dips, unlike prior crypto Septembers.
Institutions Are Buying
Public companies and treasuries continue to accumulate. The top 100 public Bitcoin treasury companies, including the likes of MicroStrategy, collectively hold 998,613 BTC. On Ethereum, Sharplink Gaming disclosed 837,230 ETH holdings as of August 31. And other big names like Bitmine exist, too, when it comes to gobbling up the ETH supply.
These players step in on dips, creating buffers that were predominantly absent in earlier cycles, at least for both BTC and ETH. Bitcoin always had an institutional following, but in this cycle, even ETH has picked up pace.
Are There Still September-Specific Risks?
Even with stronger structures, September retains its risks, although they aren’t as compelling as they were earlier.
High Profit Supply
- Bitcoin in profit: from 73.8% in Sept 2024 to 90.1% today.
- Ethereum in profit: from 69.9% to 95.9%.
Plenty of holders may lock in gains. During weaker months, with the September bias already negative, traders sitting on profit might be more susceptible to profit booking.
But there exists a hope. ETFs and treasuries absorb outflows faster than in past cycles.
Weakness in Bitcoin Withdrawal Addresses
Bitcoin withdrawal addresses fell from 37,745 (September 4, 2024) to 15,241 today. That signals softer conviction in self-custody. However, a spike to 62,977 on September 3 suggests buyers still step in on dips.
Fewer unique withdrawers generally imply less movement to self-custody and potentially softer spot accumulation. This slightly negative narrative might flip if the rate cuts come in, as BTC accumulation (primarily by ETFs) is known to improve when liquidity comes in.
With exchange reserves lower, this risk is less damaging than in past crypto Septembers, which is like a silver lining despite the withdrawal address concerns.
Macro Crosswinds
The U.S. 10-year Treasury yield at 4.22% signals higher borrowing costs and a stronger preference for safer returns. When yields are elevated, capital often shifts away from risk assets like Bitcoin, tightening liquidity and tempering bullish momentum.
Bitfinex analysts, in an exclusive bit to BeInCrypto, highlighted macro jitters as a reason for a possible correction:
“Major cryptocurrency assets endured a difficult week as macro jitters and the post-PPI sell-off weighed heavily on price action. This pullback is in line with our thesis that in the summer months BTC is likely to be prone to retracements and range trading. BTC is now down over 13 percent from its recent all-time highs, and while trading below the January peak is not an encouraging signal, we believe the market is nearing the bottom of this downturn as we move into September”, they said on Septmeber 2, 2025.
Gold at its highest level underscores a preference for safer havens.
The Fed is expected to cut rates this month, a tailwind that helped September 2024 stay green. It is worth noting that the last time the Fed cut rates in September (2024), Bitcoin saw a month of high ETF inflows. This might be an optimistic sign for the market, as highlighted in the discussion earlier.
Could This Be the September That Breaks the Curse?
For over a decade, crypto September has been synonymous with drawdowns, panic, and the worst month for crypto narrative. But 2025 presents a stronger toolkit: thinner exchange reserves, ETF demand exceeding $68 billion, doubled stablecoin firepower, and institutions that actively buy dips.
Some analysts still project the risks:
Yes, risks remain — high profit supply, weaker Bitcoin withdrawals, elevated yields. But compared to earlier cycles, mitigation is stronger. If momentum holds, this could be the crypto September that breaks the pattern.
And if new all-time highs are reached this month, something that remains a possibility with both BTC and ETH still hovering around the highs, the irony would be historic. September, once the worst month for crypto, would become the month a new cycle truly began.
The post September Is the Worst Month for Crypto — Why 2025 Could Be Different appeared first on BeInCrypto.