BTC's percentage drawdown from its all-time high — how deep below ATH the price is right now and historically.
For each day t, drawdown_t = (close_t − running_max_t) / running_max_t × 100. Always ≤ 0. Useful to visualise bear-market depth and the time spent in deep drawdown across cycles.
Drawdowns deeper than −60% have only happened at confirmed cycle bottoms (2015, 2018, 2022). −30 to −60% is normal mid-cycle pullback territory. Hovering above −20% during a bull means the trend remains healthy. The deepest historical drawdown was −84%.