Daily research · Big market days · written
What does Bitcoin do the day after the altcoins fall 4% or more?
Short answer
454 cases since 2017: in the middle one, Bitcoin moved +0.39% the day after the altcoins fall 4% or more. 56% of the cases ended higher. The best 1 in 10 reached +4.7% or more, the worst 1 in 10 −4.3% or less. Out of sample, calls like it showed no clear edge.
Typical move
+0.39%
the next day, the middle case
How often
56%
it ended higher
Best 1 in 10
+4.7%
or better
Worst 1 in 10
−4.3%
or worse
Cases
454
2017-2026, on 454 days
Higher 56% of the time against 52% on ordinary days (451 days compared): no clear edge over ordinary days.
Share on Xcopy link§ 01 · The pattern454 cases
The pattern, exactly
as of · the rule, the data, the dates
A case is a day the 100 most traded altcoins fell 4% or more on average, and the move that counts is Bitcoin's.
Each of the 454 moves is measured from the close of the day it happened to the close 1 day later.
In our data that gives 454 measured cases on 454 separate days, from Nov 10, 2017 to Oct 22, 2026; the numbers were written on Oct 25, 2026.
§ 02 · Why it might work
Why it might work
as of · the idea traders have in mind, not a promise
A drop across the biggest altcoins at once is a market-wide flush: leverage gets cut everywhere on the same day. Traders watch the next days for a relief bounce, or for the slide to continue as nervous holders step out.
That is the reasoning behind watching 4% altcoin drops; whether it held over our 454 cases since 2017 is what the next sections measure.
§ 03 · How we tested it
How we tested it
as of · our own closes, against ordinary days
- We measured each of the 454 cases from the close of the day it happened to the close 1 day later, on our own daily closes (UTC).
- Each case is set against Bitcoin's own ordinary days (1-day moves starting in the 365 days before it, at least 90 of them), and 451 of the 454 days had that many to compare.
- No two cases share a day, so each of the 454 days counts once.
- Out of sample: each calendar quarter, the lab re-ran its coin-by-coin search on the data before that quarter only, then scored every call the proven drivers of this kind made in the quarter after, against how often the same side won on any day of the same coin's quarter.
§ 04 · Results174 up · 145 down
Results
as of · every past case, Nov 10, 2017 to Oct 22, 2026
Of the 454 cases, 174 ended up, 145 down and 135 sideways (within ±1.0%) a day later; the middle case +0.39%, the average day +0.28%.
ended up (174)ended down (145)sideways, within ±1.0% (135)each line one real case · past cases, not a projection
1, 7 and 30 days against ordinary days
| After | Cases | Typical move | Typical, ordinary days | Higher | Higher, ordinary days | Against ordinary days |
|---|---|---|---|---|---|---|
| 1 day this post | 454 | +0.39% | +0.09% | 56% | 52% | no clear edge over ordinary days |
| 7 days | 226 | +0.54% | +0.68% | 53% | 54% | no clear edge over ordinary days |
| 30 days | 87 | +1.6% | +3.1% | 53% | 55% | no clear edge over ordinary days |
At the other horizons: 7 days, typical +0.54% over 226 cases; 30 days, typical +1.6% over 87 cases.
By year, the typical move ranged from −0.16% in 2024 to +1.5% in 2017; 9 of 10 years leaned the same way as the whole.
Year by year
| Year | Cases | Typical move | Higher | Lower |
|---|---|---|---|---|
| 2017 | 14 | +1.5% | 57% | 43% |
| 2018 | 77 | +0.46% | 56% | 44% |
| 2019 | 34 | +0.60% | 56% | 44% |
| 2020 | 43 | +1.1% | 77% | 23% |
| 2021 | 62 | +0.51% | 60% | 40% |
| 2022 | 60 | +0.00% | 50% | 50% |
| 2023 | 32 | +0.25% | 56% | 44% |
| 2024 | 52 | −0.16% | 48% | 52% |
| 2025 | 55 | +0.05% | 51% | 49% |
| 2026 | 25 | +0.01% | 52% | 48% |
The latest 10 cases
| Day | What happened | 1 day | 7 days | 30 days |
|---|---|---|---|---|
| The altcoins −5.8% that day | −0.28% | open | open | |
| The altcoins −6.9% that day | +1.6% | +0.11% | open | |
| The altcoins −4.6% that day | +1.1% | +0.60% | open | |
| The altcoins −4.7% that day | +0.20% | +2.7% | open | |
| The altcoins −6.8% that day | +0.01% | −0.92% | −3.8% | |
| The altcoins −4.3% that day | +0.86% | −0.20% | +8.4% | |
| The altcoins −5.5% that day | +0.25% | −0.37% | +23.9% | |
| The altcoins −9.2% that day | −0.28% | +4.1% | +4.2% | |
| The altcoins −7.0% that day | −4.4% | −0.41% | −1.2% | |
| The altcoins −6.6% that day | −3.9% | −7.5% | −7.8% |
Source: our daily closes and our dated events, measured on .
§ 05 · Out of sampleno clear edge out of sample
Out of sample
as of · calls like it, scored on data they never saw
Out of sample, calls made from 4% altcoin drops showed no clear edge: right 53% of 3,400 calls since 2019, against 50% for that side on any day (Oct 23, 2019 – Oct 22, 2026).
The bar to earn a side: right more often than that side won on any day, on 100+ scored calls over 60+ separate days, with an average move its way above 0%; the share above is that record's, not the in-sample rate of the 454 cases here.
§ 06 · Verdict
Verdict
as of · plain, with the caveats
No clear edge: 56% of 451 days ended higher against 52% on ordinary days, inside the range chance alone gives (51% to 60%).
A typical +0.39% hides a wide spread: one case in 10 was beyond +4.7% and one in 10 beyond −4.3%.
Out of sample, calls like it showed no clear edge (right 53% of 3,400 calls since 2019, against 50% for that side on any day).
Markets change, so what 4% altcoin drops did from 2017 to 2026 can stop working.
§ 07 · Questions
Questions
as of · answered from the numbers above
- How often did Bitcoin end higher the day after the altcoins fall 4% or more?
- In 56% of 454 cases from Nov 10, 2017 to Oct 22, 2026.
- Measured the scoreboard's way, day by day, the share higher was 56% against 52% on Bitcoin's own ordinary days.
- What was the typical move?
- The middle case moved +0.39% the next day.
- The best 1 in 10 reached +4.7% or more and the worst 1 in 10 −4.3% or less.
- Is this an edge?
- Not on its own: over 454 cases it shows no clear edge over ordinary days, and out of sample, calls like it showed no clear edge (right 53% of 3,400 calls since 2019, against 50% for that side on any day).
- The +0.39% typical move is the past's, and a past pattern can stop working.
- When was the latest case?
- The latest was on Oct 22, 2026: The altcoins −5.8% that day.
- A day later the move was −0.28%.
- Did it work the same every year?
- No. The typical move was +1.5% in 2017 (14 cases) and −0.16% in 2024 (52 cases).