September has long taken a bad reputation in Crypto. Both Bitcoin and Ethereum have repeatedly stumbled during this month, with a story that shows acute setbacks or dull performance. The weakest month for cryptography is considered widely, but 2025 looks different in several ways: both assets have recently touched new maximums of all time, ETF flows now shape market liquidity and rates cuts are back at the table.
The question is whether September’s weakness will weigh on cryptography, or if this cycle has changed. And if these two cryptographic unconditionals, Bitcoin and Ethereum, they will move together again, either in thick or thin. Or will there be a change of destiny for one of them?
Reservations and withdrawals exchange a mixed story
Bitcoin’s Exchange reserves fell around 18.3% since last September, while Ethereum reserves fell approximately 10.3%. This seems interesting, taking into account that both assets are quite quite close to their maximums of all time.
Both point to long -term accumulation trends, since less coins are found in exchanges ready to sell.
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But remove addresses paints a more complex image.
Ethereum retirement addresses rose from 53,333 in 2024 to more than 60,000 this year, reinforcing the upward case of a stronger autocustody and accumulation.
Bitcoin, on the other hand, saw the removal addresses of 35,347 last year to only 11,967 at the time of the publication, showing a weaker preference for self -generating and a potentially softer accumulation demand, yet. But there is more in this image.
Although Bitcoin accumulation demand seems weak on paper, it leaves space for prices growth if a positive driver arrives such as September 2025. With the history of Bitcoin of strongest ETF inputs in September compared to Ethereum, the low number of withdrawal addresses could be less a sign of weakness and more a configuration for the incoming demand.
The provision of profits and the risk of selling pressure is coming in both
Both Bitcoin and Ethereum now show a much higher percentage of gain supply that a year ago. For Bitcoin, the action increased from 76.91% in September 2024 to 88.17% in September 2025. The percentage of Ethereum increased even more, from 73.83% to 92.77%.
This means that most headlines are sitting in the profits, historically a configuration that encourages the profits.
With both assets close to the maximum record during what is generally the weakest month for cryptography, September could see greater sale pressure, unless they are compensated with structural tickets in other places. And just looking pure numbers, ETH is still a high -risk case.
ETF add a new dimension in 2025
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This year introduces a variable that the members of the last September did not have on this scale: the ETF flows. Since its launch, the Bitcoin ETFs have passed around $ 54.5 billion in tickets for life, while Ethereum ETFs, the newest product, has obtained around $ 13.3 billion.
In the last 30 days, Etfs Ethereum saw net tickets of $ 4.08 billion, compared to the exits of $ 920 million for Bitcoin ETFs. That contrast has led many to say that ETH is winning in this cycle.
But digging in September data shows a different story. By September 2025 so far, Ethereum ETF is already red with almost $ 135 million in net exits.
This repeats a similar trend as of last September, which was also negative. Bitcoin, on the contrary, began this September with $ 332 million in net tickets, similar to September 2024, when BTC ETFS registered $ 1.26 billion in earnings.
That pattern suggests that September and rates cuts have constantly favored BTC over ETH when it comes to ETF flows. Even with ETH summer tickets, its history in September shows weakness.
As Jeff Dorman said:
“BTC is gold, but very few care about gold. ETH is an application store, and investment in technology is a larger market, he said in X”
That helps explain why ETH has achieved growth capital. Even so, in the weakest month for cryptography, structural flows continue to incline Bitcoin. This possibility is what we discuss previously in the ‘Retirement Activity’ section.
The ETH/BTC ratio and market domain point to strength in Bitcoin
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The ETH/BTC ratio has gone from 0.043 last September to 0.038 today.
This decrease shows that Ethereum has a lower performance in relation to Bitcoin despite the time of the ETF, year after year.
Meanwhile, Bitcoin’s domain increased from 57.46% to 58.82% during the same period, while Ethereum’s domain fell from 15.02% to 13.79%.
In other words, even with Ethereum that shows better short -term ETF flows, Bitcoin continues to have structural leadership.
This reinforces why markets still treat BTC as the risk reference point, particularly in the weakest month for cryptography.
Short cut potential leans towards Bitcoin
Another short -term element is liquidation data. Within 30 days, Bitcoin has $ 5.24 billion in short positions stacked against only $ 1.83 billion in lengths. This imbalance increases the possibility of a brief tight if prices move higher.
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Ethereum looks more balanced, with $ 6.55 billion in shorts and $ 6.10 billion in lengths.
This inclination suggests that if September produces a surprise rise during what is generally the weakest month for cryptography, Bitcoin is better positioned to meet sharply in forced liquidations.
The X community also believes that derivatives have the key in September:
Analysts still warn about the bite
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Despite these configurations, analysts’ forecasts are still cautious. For Bitcoin, they warn that not having a support of $ 107,557 could open a deeper correction towards $ 103,931, even when the advantage remains possible if the resistance about $ 111,961 breaks.
For Ethereum, the image is equally uncertain. Analysts indicate the resistance around $ 4,579 and the downward risks if the price closes below $ 4,156. The choppy rank movement remains the base case, reinforced by a high supply of profits and divergence in the RSI signals. In a nutshell, the sales pressure would still exceed recovery attempts if the usual September narrative is maintained.
September perspective: the weakest month for crypto, but the context has changed
September has often been the weakest month for cryptography, with BTC and ETH that show little trajectory. Rare profits in 2023 and 2024 did little to change that trend.
In 2025, the configuration looks different: both currencies are almost high records, the ETFs are driving flows and another tariff cut is expected. The last cut of the September rate, a 50 PB movement in 2024, aligned with stronger bitcoin flows (remember ETF), not Ethereum.
This time, the high gain offer and the weak self -ocustody still sign up for sale. Both BTC and ETH can face winds against, but if there is upwards, Bitcoin is more likely to drive with the allegedly increased accumulation demand. Altcoins linked to Ethereum may not benefit, leaving the largest market under pressure.