Bitcoin ETF flows just reversed by more than $1.1 billion in a single trading session.

On October 21, U.S. spot Bitcoin ETFs attracted $524.8 million.

Just one day later, they recorded $635.6 million in net outflows — the largest daily withdrawal of October.

BlackRock’s IBIT accounted for $254.1 million of those outflows, while Fidelity’s FBTC lost another $217.5 million.

That’s a sharp reversal from the broadening institutional demand seen only a day earlier.

For $BTC , this matters because consistent ETF buying has been an important source of market demand.

But one negative session doesn’t establish a lasting trend, just as one strong inflow day doesn’t guarantee a rally.

The next signal is whether withdrawals continue across major funds during Friday’s trading session.

Was Thursday’s selling a temporary reaction to market volatility, or the beginning of another institutional pullback?