Coinbase has emerged as the primary custodian for U.S. Bitcoin ETFs, with over 80% of these funds relying on the platform for custody services. This dominance underscores Coinbase's significant role in the institutional crypto market, as it continues to secure partnerships with major financial entities launching Bitcoin ETFs. The reliance on Coinbase highlights the trust and infrastructure the platform has built to support large-scale institutional investments in Bitcoin. As the ETF market grows, Coinbase's position as a leading custodian is likely to influence the dynamics of crypto asset management in the U.S.