Bitcoin Dominance Pulls Back as Altcoin Season Index Remains Low

Bitcoin dominance (BTC.D) measures the percentage of total crypto market capitalization held in Bitcoin. The ratio is calculated by dividing Bitcoin's market capitalization by the total cryptocurrency market capitalization, expressed as a percentage.

In its early years, BTC.D averaged between 83 and 93 percent daily from 2009 to 2016, with little else of comparable size. However, during the 2017 ICO boom, Ethereum's launch created a platform for new tokens, dragging BTC.D down to its all-time low near 38 percent in January 2018.

The metric has since recovered, reaching 71 percent in September 2019 as the ICO bubble deflated and capital retreated to Bitcoin. The DeFi summer of 2020 and NFT mania of 2021 pulled dominance back down to the mid-40s, where it hovered through most of 2021.

In recent years, the approval of spot Bitcoin ETFs in January 2024 concentrated new institutional capital almost entirely in Bitcoin, pushing BTC.D to a four-year high above 63 percent in mid-2025. As of August 2026, BTC.D has pulled back to the mid-to-high 50s.

The Altcoin Season Index sits below 40, indicating fewer than 40 percent of the top 100 altcoins have outperformed Bitcoin over the past 90 days. The presence of spot ETFs in the market has created a new source of structural demand that did not exist in previous cycles, keeping BTC.D elevated.