BlackRock has filed an amendment for its Bitcoin ETF, requiring Coinbase, the ETF's custodian, to process withdrawals within 12 hours of a client request. The filling follows investor concerns about Coinbase's onchain settlement practices, with some questioning whether the Bitcoin ETFs were fully backed by real BTC. Coinbase CEO Brian Armstrong clarified that all ETF transactions are settled onchain, despite not sharing all ETF addresses publicly. Coinbase is the custodian for 10 of 11 spot Bitcoin ETFs and eight of the nine recently approved Ether ETFs in the US. BlackRock ETF amendment. Source: SEC