According to the source, US spot Bitcoin (BTC) ETFs recorded a $1.12B net outflow this week and US spot Ethereum (ETH) ETFs posted a $311M net outflow. Source: X post dated Oct 18, 2025. For trading, the cash-creation and cash-redemption structures used by major US spot BTC/ETH ETFs can require transacting in underlying coins during redemptions, potentially adding sell pressure and volatility during US market hours; monitor daily flow prints and NAV premiums/discounts for direction. Source: iShares Bitcoin Trust (IBIT) and Fidelity Wise Origin Bitcoin Fund prospectuses.