Hayloo’s Beta Desk — September 21, 2026.
Beta answers one question: for every 1% Bitcoin moves, how far does the other coin go? Above one, the coin amplifies Bitcoin. Below one, it damps it. The desk measures that over rolling windows of daily moves and splits it by direction. Up-capture is what a coin catches on Bitcoin’s up-days, down-capture is what it hands back on the down-days, and the gap between the two is Hayloo’s Altcoin Tax. Hand back more than you catch and you are paying the tax. Four series are read against Bitcoin, chosen by history rather than preference: ETH, Solana, XRP, and the altcoin basket (TOTAL3ES, the market without Bitcoin, ETH, and the stablecoins).
ETH’s three measurement windows disagreed this week for the first time in its 81-day run as a leader. On September 18 the 30-day beta fell from 1.32 to 1.04 in one session and finished the week at 1.10, under the 1.24 line that separates leading Bitcoin from trailing it. The 60-day window still reads 1.27 and the 120-day 1.28, so on the two longer clocks ETH remains the amplifier we have been describing since July. On the short clock it is a laggard. The beauty about viewing markets through cyclical timeframes is: you get a heads-up. We said last week, we’re short ETH. This week, we’re looking to double down on the bet.
ETH Has Led for 81 Days Against a Median of Four and a Half
ETH has led Bitcoin’s moves since early July. Across the 24 leading runs in its record the median lasts four and a half days, and this one is the second-longest since 2018, behind only the 316-day run from March 2025 to January 2026.
ETH’s run, historically speaking and backtested, is (too) long. We cut ETH short a week ago, and we were too early. This week, the beta cracks, the flag on ETH is lit, and we’re comfortable with our short position. But the entry could have been much better.
The Cross-Section
Five weeks ago XRP’s 60-day beta sat at 0.95, a hair under Bitcoin’s own pace; today it reads 1.67, its highest since September 2025.
Solana rose from 1.08 to 1.24 in two weeks and altcoins without ETH or stables from 0.84 to 0.95. ETH held between 1.26 and 1.29 the whole time. Solana, while outperforming Bitcoin, does so more violently to the downside. For 24 days, Solana has been paying the altcoin tax, a gap of −0.13, and the basket without ETH or stables pays −0.32.
ETH at +0.34 and XRP at +0.13 are the two majors charging Bitcoin for the ride. One wonders how long this could last.
XRP’s Edge Closed From the Bottom
Two weeks ago XRP had the widest edge over Bitcoin, and we said it had a maturity date. This week, XRP’s upside over Bitcoin narrowed to 13 cents on the dollar, its narrowest since June 18. Two weeks ago, XRP caught 75 cents more of every up-dollar than it handed back of every down-dollar. At the August 27 peak it was 115 cents. XRP still catches more upside than it hands back to Bitcoin. But the edge is closing. We sold all but 10 million XRP into this run.
Solana and the Altcoin Basket Bleed on Bitcoin’s Down-Days
Of every dollar Bitcoin gained, Solana caught 104 cents. Of every dollar Bitcoin lost, it handed back 117. That is 1.1 times more downside than upside, and the 24th straight day on the wrong side of the line. Solana keeps paying the altcoin tax, and so does the altcoin basket without ETH or stablecoins. Of every dollar Bitcoin gained, the basket caught 86 cents. Of every dollar Bitcoin lost, it handed back 118. That is 1.4 times more downside than upside, with the gap widening to −0.32 this week. This is the opposite of the contraction that precedes a turn in regime.
On our use of AI:
We’re a private crypto fund out of Switzerland. We built a Neurosymbolic Compound AI System for our own desk: it follows our strategies, it reads the news that affect our portfolio, it sits on a database going back decades, and brings math to our everyday emotions. We call it Hayloo. It’s our best hire. This Substack is compiled by Hayloo and written by us.
Humans have written machine-assisted for centuries. What never changes is who decides.
Nothing at Hayloo INC. was ever decided by a machine.
What we publish is what we defend as a team. When it’s wrong, it’s wrong because humans signed it.
Jordi Federer, Founder, Hayloo INC.
What’s Solid, What’s Soft
The numbers are tighter than the stories sitting on top of them. The three single-coin betas carry the smallest errors on the board, 6% for XRP, 7% for ETH, and 8% for Solana, and Solana’s 916-day run and XRP’s 33-day run have all three windows agreeing. XRP’s flag fires on contraction: its gap is closing. ETH’s fires on the contraction and on the split across its timeframes. A lit flag means the relationship with Bitcoin is moving. Every figure in this post measures the window it names. None of them says what comes next.
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