Bitcoin dominance

Bitcoin dominance divides bitcoin's market capitalization by the combined market capitalization of all the cryptocurrencies a data provider tracks, and expresses the result as a percentage. If bitcoin is worth $1.2 trillion and the whole market $2 trillion, dominance is 60%.

Traders use it to read rotation within the market. Rising dominance usually means capital is concentrating in bitcoin, often during uncertainty or the early stage of a rally, while a falling share is associated with periods when altcoins outperform, sometimes called altcoin season. Bitcoin's share was close to 100% in its early years and fell below 40% during the 2017–2018 ICO boom.

The metric has quirks. Each data provider includes a different list of assets, the growing weight of stablecoins can move dominance without any change in bitcoin itself, and thousands of illiquid tokens with inflated valuations distort the total. It works best as a broad gauge of sentiment rather than a precise signal.