Did altseason come before or after Bitcoin's peaks?

The number of documented episodes is small enough that it should be stated as a number rather than described as "several". It is a handful — fewer than ten sustained episodes across the whole published history of the measure. A pattern observed in a handful of cases is a description of those cases, not a generalisation about the market.

The episodes are also not independent. They occur within a single evolving market whose participants, venues, instruments and regulatory environment have changed substantially across the period. An episode in 2018 and an episode in 2024 are not two draws from the same process; they are two observations from a market that has been transformed in between. Treating them as a sample overstates the evidence they provide.

The practical consequence is that the finding should be stated as a description of the record rather than as a rule. "Most documented episodes followed a Bitcoin peak" is supportable. "Altseason follows Bitcoin peaks" is not, because it converts a handful of dated observations into a claim about the future. The sequence page reaches the same conclusion about the proposed BTC → ETH → alt ordering, and the cycle record holds the peak dates this page borrows.

The first limitation is the sample, stated above. The second is the dating. Both the episode boundaries and the Bitcoin peaks are identified in hindsight, and a peak is only a peak once a sustained decline has followed it. Moving a boundary by a few weeks can move an episode from one side of a peak to the other, which is a reason to treat the before-and-after classification as approximate.

The third is the universe. The breadth measure is computed over the largest assets at the time of reading, and that set changes across the period. Assets that collapsed out of the universe are absent from later readings, and assets that grew into it are present. That makes historical comparisons of the measure less clean than they appear, and it is a further reason to keep the conclusion modest.

The fourth is the distinction between timing and cause. Even where an episode followed a peak, the ordering establishes sequence and nothing more. A common factor remains a complete explanation, and no page on this site claims that Bitcoin caused an altcoin's move on the strength of co-movement alone.