Daily research · Big market days · written
What does Ether do the day after Bitcoin falls 3% or more?
Short answer
399 cases since 2017: in the middle one, Ether moved +0.86% the day after Bitcoin falls 3% or more. Higher was the outcome 58% of the time. The best 1 in 10 reached +6.6% or more, the worst 1 in 10 −6.3% or less. Out of sample, calls like it showed no clear edge.
Typical move
+0.86%
the next day, the middle case
How often
58%
it ended higher
Best 1 in 10
+6.6%
or better
Worst 1 in 10
−6.3%
or worse
Cases
399
2017-2026, on 399 days
Higher 59% of the time against 52% on ordinary days (383 days compared): higher more often than on ordinary days.
Share on Xcopy link§ 01 · The pattern399 cases
The pattern, exactly
as of · the rule, the data, the dates
A case is a day Bitcoin closed 3% or more below the day before (UTC daily closes), and the move that counts is Ether's.
Each of the 399 moves is measured from the close of the day it happened to the close 1 day later.
In our data that gives 399 measured cases on 399 separate days, from Aug 18, 2017 to Sep 15, 2026; the numbers were written on Oct 7, 2026.
§ 02 · Why it might work
Why it might work
as of · the idea traders have in mind, not a promise
When Bitcoin drops this far in a day, leveraged positions across the market get closed at once, and forced exits tend to overshoot. One reason traders watch the next days is the idea that part of the overshoot snaps back; the other view is that a drop this size can be the start of a longer slide.
That is the reasoning behind watching Bitcoin's 3% drops; whether it held over our 399 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
- Every one of the 399 cases is measured 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 Ether's own ordinary days (1-day moves starting in the 365 days before it, at least 90 of them), and 383 of the 399 days had that many to compare.
- No two cases share a day, so each of the 399 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 · Results176 up · 116 down
Results
as of · every past case, Aug 18, 2017 to Sep 15, 2026
A day later, the middle case stood at +0.86% and the average day at +0.60%; 176 cases ended up, 116 down and 107 sideways (within ±1.4%).
ended up (176)ended down (116)sideways, within ±1.4% (107)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 | 399 | +0.86% | +0.03% | 59% | 52% | higher more often than on ordinary days |
| 7 days | 213 | +0.92% | +0.50% | 55% | 53% | no clear edge over ordinary days |
| 30 days | 83 | +0.55% | +1.0% | 51% | 54% | no clear edge over ordinary days |
At the other horizons: 7 days, typical +0.92% over 213 cases; 30 days, typical +0.55% over 83 cases.
By year, the typical move ranged from −2.3% in 2026 to +2.0% in 2020; 8 of 10 years leaned the same way as the whole.
Year by year
| Year | Cases | Typical move | Higher | Lower |
|---|---|---|---|---|
| 2017 | 24 | −0.55% | 46% | 54% |
| 2018 | 78 | +0.98% | 60% | 38% |
| 2019 | 44 | +0.93% | 59% | 41% |
| 2020 | 35 | +2.0% | 74% | 26% |
| 2021 | 66 | +1.8% | 62% | 38% |
| 2022 | 48 | +0.75% | 58% | 42% |
| 2023 | 22 | +0.45% | 59% | 41% |
| 2024 | 38 | +0.47% | 55% | 45% |
| 2025 | 27 | +0.31% | 56% | 44% |
| 2026 | 17 | −2.3% | 29% | 71% |
The latest 10 cases
| Day | What happened | 1 day | 7 days | 30 days |
|---|---|---|---|---|
| Bitcoin −3.3% that day | +0.83% | +14.8% | open | |
| Bitcoin −4.4% that day | −0.87% | +5.2% | +12.8% | |
| Bitcoin −3.9% that day | −2.3% | −10.6% | −3.0% | |
| Bitcoin −6.5% that day | −2.5% | −11.8% | −8.6% | |
| Bitcoin −3.1% that day | −7.3% | −15.8% | −19.8% | |
| Bitcoin −3.2% that day | +8.1% | +3.3% | +3.8% | |
| Bitcoin −3.5% that day | +0.10% | +3.1% | +18.9% | |
| Bitcoin −3.5% that day | −3.3% | −0.16% | +12.6% | |
| Bitcoin −3.6% that day | −3.0% | −1.6% | +9.8% | |
| Bitcoin −3.9% that day | −0.46% | +5.7% | +6.6% |
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 Bitcoin's 3% drops showed no clear edge: right 52% of 7,455 calls since 2020, against 49% for that side on any day (Aug 2, 2020 – Sep 15, 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 399 cases here.
§ 06 · Verdict
Verdict
as of · plain, with the caveats
In our data Ether ended higher more often than on ordinary days (59% against 52% over 383 days), and both halves of the history lean the same way.
The typical move of +0.86% is small next to the spread between the best and worst 1 in 10 (−6.3% to +6.6%): single cases went either way by far more.
Out of sample, calls like it showed no clear edge (right 52% of 7,455 calls since 2020, against 49% for that side on any day).
Markets change, so what Bitcoin's 3% drops did from 2017 to 2026 can stop working.
§ 07 · Questions
Questions
as of · answered from the numbers above
- How often did Ether end higher the day after Bitcoin falls 3% or more?
- In 58% of 399 cases from Aug 18, 2017 to Sep 15, 2026.
- Measured the scoreboard's way, day by day, the share higher was 59% against 52% on Ether's own ordinary days.
- How big was the move the next day?
- The middle case moved +0.86% the next day.
- The best 1 in 10 reached +6.6% or more and the worst 1 in 10 −6.3% or less.
- Is this an edge?
- Not on its own: over 399 cases it shows higher more often than on ordinary days, and out of sample, calls like it showed no clear edge (right 52% of 7,455 calls since 2020, against 49% for that side on any day).
- The +0.86% typical move is the past's, and a past pattern can stop working.
- When did it last happen?
- The latest was on Sep 15, 2026: Bitcoin −3.3% that day.
- A day later the move was +0.83%.
- Did it work the same every year?
- No. The typical move was +2.0% in 2020 (35 cases) and −2.3% in 2026 (17 cases).