A guide to Bitcoin dominance and the Altcoin Season Index, and where both mislead
Bitcoin dominance sits near 60% and the Altcoin Season Index reads 59. What these gauges actually measure, and how to read them without fooling yourself.
PRICE ANALYSISALTCOINSANALYSIS
Hana Kimura
10/28/20263 min read
Two numbers dominate almost every conversation about altcoins: Bitcoin dominance and the Altcoin Season Index. On October 27 they read 60.1% and 59 respectively on CoinMarketCap. To many traders that combination looks like a contradiction. Bitcoin still controls about three-fifths of the market, yet a majority of large altcoins have beaten it over the past three months. Both statements are true, and understanding why is a good lesson in what these gauges can and cannot tell you.
What dominance measures
Bitcoin dominance is simply bitcoin's market capitalisation divided by the total market capitalisation of all crypto assets tracked by a data provider. With bitcoin worth about $1.6 trillion and altcoins together worth roughly $1.06 trillion, according to CoinMarketCap, bitcoin accounts for a little over 60%. Ether makes up about 10.6% and everything else around 29.4%.
The ratio sounds straightforward, but the denominator hides two distortions. The first is stablecoins. Dollar-pegged tokens are counted in the total market, so when stablecoin supply grows, bitcoin dominance falls even if no one sells a single bitcoin. With stablecoin supply and payment volumes expanding through 2026, part of any dominance dip reflects new dollars on-chain rather than a rotation into risk. The second distortion is the long tail: thousands of thinly traded tokens with inflated fully diluted valuations can add to the total without a matching amount of real capital behind them. For that reason many analysts watch variants alongside the headline figure, such as dominance excluding stablecoins, or the ETH/BTC price ratio, which strips out the denominator problem entirely and shows whether the second-largest asset is gaining or losing ground against the first.
What the Altcoin Season Index measures
The Altcoin Season Index takes a different approach. CoinMarketCap's version looks at the top 100 coins by market capitalisation, excludes stablecoins, and counts how many outperformed bitcoin over the past 90 days. A reading of 75 or more is labelled altcoin season, 25 or less bitcoin season, and anything in between neutral. The index stood at 59 on October 27, up from 53 a day earlier, against 60 a week before and 64 a month before. Its high for the past year was 64 on September 27 and its low was 14 on December 19, 2025.
The key word is outperformed. The index measures relative returns, not absolute gains. In a falling market an altcoin that drops 10% while bitcoin drops 15% counts as a winner. And because the index counts coins rather than weighting them by size, a cluster of small tokens rallying on a narrow theme can lift the reading while the largest altcoins drift lower. That is how a 59 reading can coexist with bitcoin above 60% dominance: plenty of mid-sized coins have done better than bitcoin, but not enough capital has moved to change the market's overall shape.
Why both gauges lag
Both indicators are slow. The 90-day window means the Altcoin Season Index still reflects price moves from late July and August, long before this month's pullback. Dominance moves faster but is driven by the largest assets, so it says little about where speculative money is going in smaller names. Treating either as a timing tool tends to produce late signals.
Derivatives data can fill some of that gap. Glassnode reported on October 21 that fewer than 5% of altcoins were paying above-neutral funding rates on perpetual futures, down from nearly a quarter in late September. Low funding means traders are not paying up for leveraged long exposure, which fits a market where altcoin enthusiasm has cooled even though the 90-day scoreboard still looks respectable.
A practical way to read them together
A useful habit is to ask what would have to happen for each gauge to confirm a genuine rotation. For a broad altcoin cycle, dominance excluding stablecoins would need to fall, ETH/BTC would need to rise, the Altcoin Season Index would need to push through 75 and funding on altcoins would need to turn positive without immediately overheating. Each of those measures something different, so agreement among them carries far more weight than any single reading.
Right now the evidence points the other way on most counts. Bitcoin's share is holding above 60%, ether's share has slipped slightly from 10.7% a week earlier, and leveraged demand for altcoins is close to the bottom of its two-year range. The index's neutral reading reflects selective strength in individual tokens rather than a market-wide shift.
None of this makes the gauges useless. Dominance is a quick read on risk appetite, and the Altcoin Season Index is a fair summary of the past three months. The mistake is treating either one as a forecast. They describe where money has already gone, and in a market that often reverses at the edges, that is a starting point rather than an answer.