The altcoin market Capital is just a few percentage points away from All-Time-High . Many analysts believe it could reach much higher levels in September.
There are many reasons that suggest the altcoin season has entered a phase of acceleration, where almost any altcoin purchase can be profitable. What are those signs? Here are the key observations and explanations.
1. Altcoin volume market share surpasses ETH and Bitcoin
Analyst Maartunn recently noticed that altcoin volume surged in September while BTC and ETH volumes declined. This rare signal confirms Capital is flowing into altcoins .
Data from CryptoQuant also shows that in September, the share of altcoin spot volume increased while that of ETH and BTC decreased. Specifically, altcoins accounted for 37.2%, while ETH and BTC accounted for 31.8% and 30.9%, respectively.
BTC, ETH and Altcoin volume ratio. Source: CryptoQuantThis shift often signals a rotation of liquidation from Bitcoin and large- Capital coins to Medium and small- Capital coins, confirming the acceleration of the altcoin season.
“Signs of altcoin season? Ethereum spot volume has been down over the past week, while altcoin volume has been up,” Maartunn said .
The decline in ETH 's volume share fits the well-known Capital rotation cycle. Capital typically starts with a Bitcoin rally, flows into ETH , and accelerates into a broader altcoin boom.
Maartunn added that eight out of 10 indicators in CryptoQuant's Bull/bear score are currently showing a bearish bias for Bitcoin.
BTCD, Bitcoin Price, and Altcoin Market Capital (TOTAL3). Source: TradingView .Meanwhile, BTCD has declined along with BTC price in September. With the altcoin market Capital rising, this reinforces the view that Capital is favoring altcoins.
2. Altcoin season index hits 2025 high
The second sign is the Altcoin Season Index (ASI) from Blockchain Center, which reached 80 points, the highest level in 2025. This confirms that the market is in altcoin season.
The ASI measures the performance of the top 50 coins (excluding stablecoins) against Bitcoin over the past 90 days. With 75% of coins outperforming BTC, the index shows that altcoins are dominating.
Altcoin Season Index. Source: Blockchain CenterDuring the bull phase, ASI can climb to 100 before the cycle ends, similar to previous peaks. This reflects strong appetite for high-risk altcoin investments.
Analyst Lau noted that the altcoin season’s acceleration phase could last anywhere from 17 to 117 days.
“History shows that the Medium length of an alt season is 17 days, with a record of 117 days. Now we just have to wait and XEM how long the new cycle will last,” Lau said .
3. TOTAL3 forms a large ascending triangle
The third sign comes from technical analysis. TOTAL3 (total altcoin market Capital excluding BTC and ETH) has formed a large ascending triangle over the past four years and is now on the verge of a breakout.
The chart shows TOTAL3 testing monthly all-time highs, with volume and price increasing to pressure resistance. A breakout would officially mark a strong acceleration of the altcoin season, similar to the 2019–2021 cycles.
Simon Dedic, founder of MoonrockCapital, calls this the most important structural signal right now.
Altcoin Market Capital (TOTAL3). Source: Tradingview/Simon Dedic“Imagine calling a top when TOTAL3 is on the verge of breaking out of a 4-year wedge pattern, on track to hit the highest monthly close in crypto history,” said Simon Dedic.
If TOTAL3 breaks above $1.16 trillion to set a new high, it will boost investor confidence in the altcoin. With no historical resistance to reference, the peak of this rally will be entirely dependent on retail investors' FOMO momentum.
4. Exchanges like Upbit, Coinbase and Bithumb increase listings
Increased liquidation in altcoins has fueled a wave of new listings on exchanges in September.
- Upbit added nearly one Token per day (LINEA, PUMP, Holo, OPEN, WLD, FLOCK, RED) to maintain a market share of 50.6% over Bithumb (46%).
- Bithumb has listed EUL, WLFI, LINEA and PUMP.
- Coinbase has listed KMNO, DOLO, LAYER, SPX, AWE, and WLFI.
These listings increase liquidation for altcoins, attract speculation, and increase volume. The feedback loop between listing news and increased volume further fuels the altcoin season .
