Altcoin season

Altcoin season, or "altseason", is a period when many altcoins (cryptocurrencies other than bitcoin) rise much faster than bitcoin. One popular definition, used by some data sites' "altcoin season index", is when around 75% of the top 50 coins outperform bitcoin over the previous 90 days.

Historically, strong altcoin seasons occurred in early 2018 and in 2021, often after bitcoin had already rallied and traders rotated profits into riskier, smaller tokens. Falling bitcoin dominance is the usual sign. These phases tend to be short and end in sharp crashes, with many smaller coins never recovering their highs.

Altcoin seasons have become less predictable as the number of tokens has exploded, spreading new money across thousands of projects, and as institutional money via ETFs has concentrated in bitcoin. Anyone chasing an altseason should remember that most altcoins lose value over the long term relative to bitcoin.