Bitcoin dominance falls below 60%, signaling potential altcoin season

Bitcoin’s grip on the crypto market is loosening. BTC dominance, the metric tracking Bitcoin’s share of total cryptocurrency market value, has slipped to 58.5% as of September 26, after failing to hold above the psychologically important 60% threshold.

The numbers behind the narrative

Glassnode’s Altcoin Cycle Signal, which measures conditions favorable for altcoin outperformance on a 0 to 100 scale, hit 81.25 on September 22.

The altcoin market cap, excluding Bitcoin, has climbed to roughly $1.17 to $1.19 trillion in late September. That represents a 33% increase since mid-August.

Bitcoin itself has been trading around $84,000, following a brief push toward the $86,000 to $87,000 range. The total crypto market cap has reclaimed $3 trillion.

Yet the Altcoin Season Index, a separate gauge that tracks whether altcoins are broadly outperforming Bitcoin, has remained in the neutral-to-Bitcoin-led zone. Recent readings have landed between 45 and 53, well below the 75 threshold that would confirm a full-blown altseason.

Why this cycle looks different

In 2017 and 2021, declining Bitcoin dominance was the starting gun for explosive altcoin rallies. During those cycles, BTC dominance fell from above 60% to 70% all the way down into the 40% to 50% range as capital flooded into altcoins.

The 2026 landscape is structurally different. Bitcoin ETFs have become a dominant force in crypto capital allocation, funneling institutional money directly into Bitcoin. Institutional investors buying Bitcoin through ETFs aren’t typically the same crowd moving into small-cap altcoins on decentralized exchanges.

Reading the tea leaves

The divergence between Glassnode’s signal and the broader Altcoin Season Index is worth unpacking. Glassnode’s metric focuses on on-chain conditions, measuring whether the plumbing of the crypto market is set up for altcoin flows. The Altcoin Season Index looks at actual price performance relative to Bitcoin.

For traders watching this setup, the 60% dominance level is the line in the sand. Bitcoin’s repeated failure to reclaim and hold above that mark suggests sellers are stepping in at that zone. If dominance continues drifting lower toward the mid-50s, it would strengthen the case for broader altcoin strength.

The 33% altcoin market cap surge since mid-August is significant, but many altcoins are still far below their all-time highs from previous cycles. A 33% move off deeply depressed levels is recovery, not euphoria.

If the next wave of crypto adoption continues to be channeled primarily through Bitcoin ETF products, the capital available for altcoin rallies could be structurally smaller than in prior cycles where ETF-driven flows did not exist.