Research · test #9
Does buying the Bull Market Support Band work? No edge
The popular rule: "always buy once bitcoin touches the Bull Market Support Band" - the zone between the 20-week simple and 21-week exponential moving averages. We wrote the rules down first and counted every touch since 2018, including the ones nobody posts charts of. The touch did not beat buying on any other day of a bull market, and the average result rests on one episode.
In short: 17 touches, 2018 to 2026, bought at the close of the touch day and held 90 days: average +4.7% after costs, median +0.4%, 10 of 17 in profit. A random day in a bull-market context averaged +18.3%. Without the single best episode (September 2020, +86%) the average is -0.4%. In 11 of 17 touches the band broke within four weeks.
The rules (fixed before the run)
- The band: 20-week simple moving average and 21-week exponential moving average of weekly closes (Binance BTCUSDT spot, weeks from Monday UTC). Top = the higher of the two, bottom = the lower. The week still in progress is not used.
- Bull context: the last two completed weekly closes were above the band's top - so price comes from above, as the "support" idea assumes.
- Touch: the day's low reaches the band's top while the previous day's low was still above it.
- Control: random days in the same bull context, 10,000 samples of the same size. If the touch matters, it should beat them.
- Edge requires: average above zero, t above 2 and p below 0.05 against the control on 2018-2022 and 2023-2026 separately, with at least 8 touches in each (bitcoin has had only a few cycles, so we cannot ask for 30).
Result: no edge
| 90-day hold | Touches | Average | Median | In profit | t | p vs control | Control average |
|---|---|---|---|---|---|---|---|
| 2018-2022 | 8 | -1.53% | +0.05% | 50% | -0.11 | 0.91 | +29.65% |
| 2023-2026 | 9 | +10.26% | +5.50% | 67% | 1.17 | 0.39 | +8.43% |
| All | 17 | +4.71% | +0.44% | 59% | 0.59 | 0.87 | +18.33% |
The result does not clear the bar in either period. On the first period the touch averaged slightly below zero while a random bull-market day made +29.7%. On the second, +10.3% is not distinguishable from luck with nine touches (t 1.17). Buying on a random day of the period at any time made +13.3% on average, more than the touch.
Every touch, 90 days later
Ten bars are green and seven red. The greens average +24% and the reds -23%, so the outcome hangs on the size of a few bars: take out the single best touch (September 2020, +86%) and the average of the other 16 is -0.4%. The worst touches - April 2022 (-53%), September 2019 (-23%), December 2021 (-21%) - are the ones the band failed to hold.
| Touch date | BTC close | 30 days | 90 days | 180 days | Worst dip in 90 days | Band broke within 4 weeks |
|---|---|---|---|---|---|---|
| 2018-02-01 | $9,225 | +24.1% | +0.1% | -16.4% | -35% | yes |
| 2019-09-23 | $9,702 | -23.2% | -22.9% | -36.4% | -34% | yes |
| 2020-02-26 | $8,785 | -27.8% | +0.4% | +33.5% | -57% | yes |
| 2020-09-04 | $10,446 | +1.9% | +85.7% | +381.8% | -6% | no |
| 2021-05-13 | $49,671 | -28.6% | -8.6% | +34.6% | -42% | yes |
| 2021-09-07 | $46,864 | +14.6% | +7.4% | -18.2% | -15% | no |
| 2021-12-03 | $53,601 | -12.0% | -21.0% | -44.6% | -39% | yes |
| 2022-04-06 | $43,170 | -16.8% | -53.5% | -54.7% | -59% | yes |
| 2023-03-09 | $20,362 | +37.0% | +29.2% | +26.5% | -4% | no |
| 2023-06-05 | $25,728 | +18.4% | +0.7% | +53.1% | -4% | no |
| 2023-08-17 | $26,623 | -0.4% | +42.0% | +86.5% | -6% | yes |
| 2024-07-30 | $66,188 | -10.5% | +5.5% | +54.8% | -26% | yes |
| 2024-09-30 | $63,328 | +14.0% | +47.8% | +30.3% | -7% | no |
| 2025-02-25 | $88,680 | -1.8% | +23.2% | +27.8% | -16% | yes |
| 2025-08-30 | $108,816 | +4.9% | -16.7% | -38.2% | -26% | no |
| 2025-10-10 | $112,774 | -7.3% | -19.4% | -37.2% | -29% | yes |
| 2026-05-13 | $79,314 | -20.0% | -20.0% | - | -27% | yes |
What else we looked at
- The median dip inside the 90 days was -26%, and 10 of 17 touches dropped more than 20% below the entry before the 90 days were up. Buying the touch required sitting through a large drawdown most of the time.
- The 180-day exit looks much better (average +30% over 16 touches, 9 in profit) - but it is a secondary exit, no control was run for it, and it leans on the same 2020 episode (+382%). We do not count it toward the verdict.
- The bottom of the band instead of the top: 15 touches, average +3.9% (t 0.55) - first period -9.7%, second +15.9%. Also no edge.
- By period: the band broke within four weeks in 6 of 8 touches in 2018-2022 and in 5 of 9 in 2023-2026.
What this test does not say
- Seventeen touches over a few cycles is a small sample, and touches within one cycle are related. A different definition of "bull context" or "touch" gives a different list; this is the one written before the run.
- Popular charts include the unfinished week in the averages, so their band is slightly different from ours.
- Only a plain spot purchase with a 0.2% round-trip cost. No leverage, no stop-loss, no scaling in - those are different strategies.
- "No edge" means that, as a rule and on this data, buying the touch did not beat buying on other bull-market days. It does not say the band is meaningless as a reference level.
Data and method
Rules and criterion were committed before any calculation, and the code before the run; every touch is listed above. Data: Binance spot BTCUSDT weekly and daily candles (public API), 17 August 2017 to 20 October 2026. Same approach as our other tests: a control group, two periods, costs included. Related: the rainbow chart without hindsight (another "buy the cheap zone" rule), Uptober, bitcoin monthly returns, and all tests in one table.
FAQ
What is the Bull Market Support Band?
The area between the 20-week simple moving average and the 21-week exponential moving average of bitcoin's weekly closes. Traders treat it as support in bull markets and say to buy when price falls back to it.
Does buying the Bull Market Support Band work?
Not in our test. In 17 touches from 2018 to 2026, buying at the first touch from above and holding 90 days averaged +4.7% after costs, median +0.4%, 10 winners out of 17. A random bull-market day averaged +18.3% and any day +13.3%. The average rests on one episode, September 2020 (+86%).
Does the band hold as support?
Often not. In 11 of 17 touches (65%) a weekly close fell below the bottom of the band within four weeks: 6 of 8 in 2018-2022 and 5 of 9 in 2023-2026.
What is the Bull Market Support Band for bitcoin today?
It moves every week with the two averages. Compute it from weekly closes. This page tests the rule; it does not publish a current price level. Compare other models on our rainbow chart.
Is this financial advice?
No. It is a test of a popular rule on past data. Seventeen touches across a few cycles is a small sample, and a result that did not hold in the past can still happen in the future, and the reverse.