Altcoin Season Index Has Crashed To 29 After Its September 2025 Highs

Back in September 2025, the Altcoin Season Index, which tracks the performance of the top 100 altcoins against that of Bitcoin, had reached a new yearly peak. This rise had triggered positive sentiment in the market, with calls for the altcoin bull run to finally begin. However, the tide has since turned, and hopes for another altcoin season have been dashed. Now, the index has crashed back downward, moving toward its yearly lows.

Altcoin Season Index Falls To 39 From 78

The Altcoin Season Index on the CoinMarketCap website has declined to a score of 29, representing an over 50% crash from its September highs. Back then, the Altcoin Season Index had climbed to a score of 78, suggesting that altcoins were in a bull market. However, this move was short-lived with the market crash that followed, especially in the month of October.

This index takes into account how the top 100 altcoins by market cap have performed against the Bitcoin price over a 90-day period and uses it to score the chart. The more altcoins are outperforming Bitcoin during this timeframe, the higher the score on the index.

A score of 29 means that only 29 altcoins of the top 100 have seen better performance compared to the Bitcoin price over this 90-day period. The likes of Binance-backed ASTER and ZCASH’s ZEC lead this list after seeing an over 900% increase each during this time.

Interestingly, the Ethereum price appears in the list of altcoins outperforming the market leader, coming in with a 5.18% increase for ETH compared to the 4.32% decline suffered by Bitcoin at the time of writing.

What This Means For Altcoins

The current score of 29 on the Altcoin Season Index represents the poor performance of altcoins over the last few months, as they were especially rocked by the October 10 crash. However, this is not completely bad news for the altcoin market, going by historical performance.

Looking back, a bull run has always begun when the index falls to low levels. Before the September 2025 rally, the Altcoin Season Index had fallen below 40 before marking a bottom. Thus, the current low index score, coupled with market sentiment declining into fear, could suggest that a bottom is close.