Bull Market Support Band

It's the range between two moving averages of Bitcoin's weekly close: the 20-week simple moving average (20W SMA) and the 21-week exponential moving average (21W EMA). Both track roughly the same five months of price action, but the EMA weights recent weeks more heavily, so the two lines diverge slightly and trace out a band rather than collapsing into a single line.

20 and 21 weeks — roughly one quarter — is long enough to filter out normal weekly volatility but short enough to still react within a market cycle.

The sparkline shows how far spot price sits above or below the band's midpoint over the trailing ~4 years, in percent. Sustained readings above zero mean price is holding over the band — the healthy-uptrend condition. A move below zero that persists for several weeks is the warning sign: price has lost the band, historically the setup for a trend change rather than a routine dip.

During an uptrend, price dipping into the band has repeatedly resolved as a buyable pullback rather than a trend change — the band has held as support through every Bitcoin bull market since 2016. A sustained break — the 21W EMA crossing below the 20W SMA and holding for several consecutive weeks, filtering out short whipsaws — has historically marked the transition from bull market to bear market rather than just a deeper pullback.

The band is a trend-health filter, best read weekly, not daily: is price above the band (uptrend intact) or has it lost it on a sustained basis (trend at risk)? Because it's price-only and lagging, it works best paired with a valuation gauge that describes how stretched the move is — the Mayer Multiple and MVRV Z-Score answer "how extended?" while the band answers "is the trend still intact?"

Momentum and trend signals of this kind sit in the momentum & sentiment family the Risk Model blends alongside valuation, cycle, and on-chain families. The model reads trend health as a continuous input rather than waiting for a binary band break, so rising or falling risk registers before a clean crossover confirms it. See the Methodology page for the family weights.

Like any moving-average-based signal, the band lags price — it confirms a trend change after it has started, not before. And past band behavior isn't a guarantee of future behavior: it has held reliably across Bitcoin's history so far, but a structurally different future cycle isn't bound to repeat the pattern. Whipsaws around the band during choppy, range-bound markets are the most common way it produces false signals.