Bitcoin dominance, or BTC.D, measures Bitcoin’s share of total crypto market value. It is calculated as Bitcoin market capitalization divided by total crypto market capitalization, multiplied by 100. Data providers calculate it slightly differently; CoinGecko currently puts Bitcoin dominance around 58%, excluding certain wrapped, bridged and staked tokens to reduce double counting.
Rising Bitcoin dominance means Bitcoin is gaining market share relative to altcoins. Historically, falling dominance often accompanied altcoin rallies. In 2017, CoinMarketCap recorded Bitcoin dominance at 85.4% in February before Ethereum, XRP and ICO-era tokens expanded their share. However, Bitcoin’s price direction alone does not explain relative performance: if BTC rises while dominance falls, altcoins are appreciating faster.
CoinMarketCap’s Altcoin Season Index has fallen to 35, down five points from the previous day. The index compares the 90-day performance of Bitcoin with the top 100 altcoins, excluding stablecoins and wrapped tokens. A reading below 50 generally indicates a 'Bitcoin season,' while above 75 suggests a strong altcoin season. The current reading shows Bitcoin is outperforming most major altcoins, even though selected tokens can still rally individually. XRP recently gained 43.7% in seven days while BTC dominance remained near 59%, showing single-token strength does not confirm market-wide altseason.
The recent dip comes amid a mixed week for cryptocurrencies. Bitcoin has held above key support levels, while several mid-cap altcoins corrected. Regulatory clarity around Bitcoin ETFs and institutional adoption has reinforced Bitcoin’s role as 'digital gold,' drawing capital away from riskier altcoins. Coinpaper’s recent market rotation showed altcoins added roughly $215 billion in three days, yet elevated Bitcoin dominance prevented a convincing broad-based altseason.
For investors, the Altcoin Season Index is a lagging indicator based on 90-day performance. A lower reading can encourage rotation into Bitcoin or cash, but it does not predict the future. Historically, Bitcoin seasons have preceded altcoin rallies as BTC profits rotate into smaller cryptocurrencies. Traders should monitor the index alongside trading volume, on-chain activity and market sentiment.
