Bitcoin Dominance (BTC.D) measures Bitcoin's share of the total cryptocurrency market capitalization. It signals where capital is flowing within crypto — toward Bitcoin or toward altcoins.
What dominance shifts mean
Rising BTC.D = Bitcoin outperforming altcoins. Often happens in: bear markets (flight to crypto "safety"), early bull market phases, or after major altcoin failures. Falling BTC.D = "altcoin season" — riskier altcoins outperforming as capital rotates into higher-beta assets.
Key levels
Historic range: 35% (2017 ICO mania, 2021 DeFi/NFT boom) to 70%+ (Bitcoin-dominant phases). The 50-60% range is often considered "normal." Sharp moves up usually coincide with risk-off; sharp moves down with altcoin rallies.
What it means for your finances
If you hold both BTC and altcoins, dominance helps with rebalancing decisions. Rising dominance = consider trimming alts. Falling dominance with overall market up = altcoins are leading. Note: dominance can fall both because Bitcoin drops OR altcoins rise faster — context matters.