ETFs are the BTC impulse: +$1B flow ≈ +3.5 pts
An important number: β_ETF = 3.50
In this sample, every +$1B of monthly spot ETF net inflows is associated with about +3.5 percentage points of BTC monthly return (r = 0.782, p < 0.001).
If ETFs pull in +$4B net this month, that’s roughly a +14% tailwind (4 × 3.5) all else equal.
If flows flip to -$4B, that’s roughly a -14% headwind.
BTC trades on the margin. The float is thin.
ETFs are the largest marginal bid.
flows rising = bullish
flows reversing = bearish
Watch the flow