What Is the Bull Market Support Band?
The Bull Market Support Band (BMSB) is a popular crypto technical indicator made up of two weekly moving averages plotted together as a band. The area between the two lines tends to act as support during bull markets and as resistance during bear markets — which is where the name comes from.
The two lines
- 20-week SMA — the simple moving average of the last 20 weekly closes. It weights every week equally and reacts slowly.
- 21-week EMA — the exponential moving average over 21 weeks. It weights recent weeks more heavily, so it reacts a little faster than the SMA.
Plotted together, the two lines form a band rather than a single level. The small gap between them is the “support band.”
Why traders watch it
Because it is built from weekly data, the BMSB filters out day-to-day noise and gives a read on the longer-term trend. Historically, major crypto assets have spent bull markets holding above the band and bear markets trading below it, so the band is used as a simple regime filter.
Above, inside, or below
- Above the band — price is over both moving averages; the band tends to act as support and the trend is generally read as bullish.
- Inside the band — price is between the two averages; a zone of indecision near the longer-term trend.
- Below the band — a weekly close under both averages; often read as a loss of momentum, with the band acting as resistance.
Limitations
The BMSB is a lagging indicator: moving averages are built from past prices, so the band reacts after moves have begun. In sideways or choppy markets price can cross the band repeatedly (whipsaw). It is also just one lens — it says nothing about fundamentals, liquidity, or news. It is not a guaranteed market signal and should be combined with other analysis and risk management.
Why values differ between platforms
Different sites can show slightly different band values because of how they define the weekly candle (which day the week starts, and the timezone), how they treat the current in-progress week, and which exchange’s price feed they use. This site documents its exact approach on the methodology page.
Frequently asked questions
What is the Bull Market Support Band?
The Bull Market Support Band (BMSB) is a technical indicator made up of two weekly moving averages — the 20-week simple moving average (SMA) and the 21-week exponential moving average (EMA). The zone between them often acts as support during bull markets and resistance during bear markets.
What does it mean when an asset is above the band?
When price trades above both the 20-week SMA and 21-week EMA, the band tends to act as support and the longer-term trend is generally considered bullish.
What happens when an asset falls below the band?
A weekly close below the band is often read as a loss of bullish momentum, with the band then frequently acting as overhead resistance. It is a signal of trend weakness, not a guaranteed reversal.
Which timeframe does the BMSB use?
It is a weekly indicator: the 20-period SMA and 21-period EMA are calculated on weekly candles, which is why it reflects the longer-term trend rather than short-term moves.
Is the Bull Market Support Band a reliable signal?
It is a trend-context tool, not a guaranteed buy/sell signal. Like all moving-average indicators it lags price, can whipsaw in choppy markets, and should be combined with other analysis and risk management.
See the live Bull Market Support Band dashboard for the current band status of the top 100 cryptocurrencies.