BlackRock has filed an amendment for its Bitcoin ETF, requiring Coinbase, the custodian, to process Bitcoin withdrawals within 12 hours after a client request. This move addresses growing investor concerns about Coinbase’s on-chain settlement practices and fears of "paper BTC" (Bitcoin IOUs) suppressing prices. Coinbase’s CEO, Brian Armstrong, reassured investors that all transactions are settled on-chain and undergo annual audits. Despite these concerns, BlackRock’s iShares Bitcoin Trust remains the largest Bitcoin ETF, and analysts argue that native Bitcoin holders, not ETFs, are responsible for recent price stagnation. Source: Cointelegraph