The Altseason Fair Value Band, explained

Fair value

0.51

altcoin market cap over Bitcoin, since 2017

Cycle-top line

1.00

+1.5σ — risk reads 100

Cycle-bottom line

0.26

−1.5σ — risk reads 0

History

2017 →

daily, the fit window and the chart

One ratio: the market cap of every altcoin — total crypto market cap except Bitcoin, Ethereum, stablecoins and tokenized real-world assets — divided by Bitcoin’s market cap. At 0.35 the altcoin market is worth thirty-five percent of Bitcoin; at 1.00 it is worth as much as Bitcoin. The ratio only moves when altcoins gain or lose ground relative to Bitcoin, which is exactly what an altseason is and exactly what a dollar chart hides.

Around that ratio sit three flat lines. The fair value is the ratio’s average over every day since 1 January 2017: 0.513. The cycle-top line sits 1.5 standard deviations above it at 1.00, and the cycle-bottom line 1.5 below at 0.263. The chart shows the whole daily history from 2017 on a log scale, so the two outer lines sit at equal distances from the middle one.

The Log Regression Band for Bitcoin and Ethereum rises over time, because each coin’s price has grown with time and a curve fitted through that history rises with it. The altcoin ratio has done no such thing. Its cycle peaks have come in lower each time — 1.59 in January 2018, 1.02 in May 2021, 0.61 in December 2024 — while its bottoms have come in higher: 0.08 in 2015, 0.19 in 2020, 0.29 in 2026.

Fitting the Bitcoin-style rising curve to that history gives a model that explains less than half of the ratio’s movement, puts fair value at 0.74 while the ratio stood at 0.35 on 4 October 2026, and keeps lifting a top line that every altseason falls further short of. The ratio does not trend; it swings around an average and comes back. So the band is the average and the usual size of the swing, held flat.

The risk level is the ratio’s position between the two outer lines, measured in log space so it matches how the lines were drawn. At or below the cycle-bottom line it reads 0. At or above the cycle-top line it reads 100. On the fair-value line, exactly halfway between them in log terms, it reads 50. Between the lines it climbs smoothly and only ever upward as the ratio rises: the geometric midpoint between the bottom line and fair value reads 25, between fair value and the top line 75.

Because the lines are constants, the same ratio always produces the same risk level, on any day, in any year. A reading of 22, where the ratio stood on 4 October 2026, means the ratio is a tenth of the way, in log terms, from the historical floor toward the historical ceiling — nothing more and nothing less.

The average and the width were fitted once, over the daily ratio from 1 January 2017 to the fit date, and then frozen as constants — the same arrangement the Log Regression Band uses for its band settings. The candidates were judged on one question: how close does the risk level read to 100 at the three altseason peaks (January 2018, May 2021, December 2024) and to 0 at the three altwinter lows (December 2015, May 2020, April 2026)? Several windows and widths were compared. The 2017 window with a 1.5-sigma width came closest, reading 100 / 100 / 62 at the peaks and 0 / 8 at the two lows inside its window.

Two of the alternatives are worth knowing about. A 2-sigma width lets only the 2018 peak reach 100. A window that includes 2013–2016 pulls the average down to 0.34 and turns the 2020 and 2026 lows into neutral readings in the twenties and forties, because the thin, pre-stablecoin altcoin market of those years sat permanently under 0.2.

The 2024 peak reads 62, and that is the point. The band does not grade every altseason a 100; it grades each one against how far altcoins have ever got against Bitcoin.

The white line is the ratio, on its own right-hand axis with a log or linear toggle. The red line is the cycle top, the dashed purple line the fair value, the blue line the cycle bottom. All three are the same across the whole chart.

The coloured line is the risk level, on the fixed 0–100 left-hand axis and painted on the same heat scale as every other risk surface here: deep blue at the bottom of the range through amber in the middle to red at the top. Readings at or below 20 shade the background blue; at or above 80 they shade it red.

The strip above the chart shows today’s ratio, its percentage distance to fair value, the same distance counted in standard deviations with its zone label (Deep value through Euphoria / Cycle top, the Log Regression Band’s vocabulary), and how far the ratio is from the cycle-top line.

A fixed band is honest about the past and silent about structural change. If altcoins never again reach parity with Bitcoin, the top line stays at 1.00 and the risk level never again reads 100 at a peak — as it did not in 2024. If they one day far exceed it, the reading pins at 100 while the ratio keeps climbing. The lines describe the range the ratio has lived in since 2017; refitting them is a deliberate decision, not something the chart does on its own.

There is also no dollar in this chart at all. Altcoins can read 0 and still be falling in price, because Bitcoin is falling faster; they can read 100 while everything, Bitcoin included, is rising. The band answers one question — how altcoins stand against Bitcoin by their own history — and nothing about either side in isolation.

This is the simplest of the three altcoin-versus-Bitcoin reads on this site, and the one with the longest memory. The Altcoin Season Index is CoinGlass’s published daily series. The Altcoin Strength Index ranks the weekly ratio against a moving two-to-five-year window and nudges the result for momentum, so it answers “cheap or expensive by recent standards?”. This band holds the daily ratio against one fixed average over the whole modern history, so it answers “where are we between the floor and the ceiling altcoins have actually reached?”. None of the three feeds another; they are worth reading side by side.

Others in market structure — How much borrowed money is in the market, which way bets are leaning, and where money is moving.

• Gaussian Channel Trend ZonesWeekly Bitcoin through a very smooth Gaussian filter: the zones where the filter falls, what happened around them in earlier cycles, and a 0–100 risk level.
• Bull Market ProgressHow far roughly thirty cycle-peak indicators have travelled toward their historical top readings.
• AstrologyBitcoin’s four-year cycle as one lap of a ring, from bottom through top to the next bottom, plus altcoins orbiting by size and momentum.
• Funding RateWhat leveraged traders pay to hold their positions — the cost of crowd consensus.
• Alt Open Interest ShareThe share of futures open interest held by five major altcoins against Bitcoin, ranked against its own history.

Every indicator we track — the full glossary.