Crypto terminology related to altcoin wallets includes key terms like private keys, public addresses, and seed phrases, crucial for secure transactions.
An Altcoin Index is a benchmark that tracks how alternative cryptocurrencies- any coin other than Bitcoin are performing collectively, rather than one at a time.
Instead of watching dozens of individual charts, traders use an index to get a single read on whether capital is flowing into altcoins or staying parked in Bitcoin.
The most widely cited version of this is the Altcoin Season Index, originally built by Blockchain Center and now also published by CoinMarketCap.
It’s become the de facto standard reference point whenever someone says “altcoin index” in a trading context.
How the Altcoin Season Index Is Calculated
The index compares the top 100 coins ranked on CoinMarketCap, excluding stablecoins and wrapped tokens, based on their rolling 90-day price performance against Bitcoin.
The original Blockchain Center version uses the top 50 instead of the top 100, so the two can occasionally show slightly different readings on the same day.
The scoring works like this:
75–100: Altcoin Season — at least 75% of the tracked coins have outperformed Bitcoin over the past 90 days Bitget
25–75: Neutral/transitional phase — no broad rotation confirmed yet
0–25: Bitcoin Season — 25% or fewer of the tracked coins are beating Bitcoin
The index refreshes daily and is scaled from 1 to 100.
As of mid-2026, the index has spent most of the year in Bitcoin-led territory. Through 2026, the index has largely read in the 30s to mid-40s, with Bitcoin dominance holding near 58–60%.
It briefly rebounded toward the neutral-50 mark in May 2026 before pulling back again.
The last sustained push above the 75 Altcoin Season threshold came in September 2025, when it touched the high 70s before retreating.
What’s changed compared to previous cycles: capital rotation has become more selective, favoring specific assets with institutional-grade signals like active ETF demand or real on-chain revenue, rather than lifting altcoins broadly as a category.
Why the Index Matters to Traders
Diversified read on sentiment — instead of guessing from one coin’s price action, the index reflects market-wide rotation.
Timing signal, not a guarantee — a high reading tells you altcoins have been winning, not that they will continue to.
Confirmation tool — experienced traders pair it with other signals like Bitcoin dominance trend, ETH/BTC and SOL/BTC pairs, and on-chain liquidity flows before acting on it.
Different platforms (CMC’s top-100 version vs. Blockchain Center’s top-50 version) can disagree slightly on any given day.
A rising index during a period of thin, narrative-driven pumps (a single sector spiking) can look like altseason without reflecting genuine broad rotation.
It’s a backward-looking, 90-day measure — it confirms what already happened rather than predicting what’s next.
Frequently Asked Questions
Is the Altcoin Season Index the same as an “Altcoin Index”?
In practice, yes — when people search altcoin index, they’re almost always referring to the Altcoin Season Index, since it’s the standard benchmark the market has settled on.
What does it mean when the index is above 75?
It means at least 75% of the tracked altcoins have outperformed Bitcoin over the trailing 90 days; the market is officially in Altcoin Season territory.
Can the index be wrong?
The index reflects historical price data accurately, but a high reading doesn’t guarantee the trend continues, and it can be skewed by narrow, sector-specific rallies rather than genuine broad-based rotation.
