
US spot Bitcoin ETFs now hold about $78 billion in assets, with BlackRock's iShares Bitcoin Trust (IBIT) controlling $47.5 billion, or roughly 61% of all Bitcoin in US spot ETFs. Since its launch in January 2024, IBIT has attracted $50-$63 billion in net inflows, highlighting strong institutional demand. This concentration means over 5.7% of Bitcoin's circulating supply is locked in regulated ETFs, impacting market dynamics and liquidity risks. Investors should note the dominance of BlackRock and consider alternatives like Fidelity's FBTC to diversify ETF exposure.