Bitcoin exchange-traded funds (ETFs) from BlackRock and Fidelity have seen significant inflows this year, accounting for 26% and 56% of their total ETF inflows respectively. BlackRock's iShares Bitcoin Trust (IBIT) and Fidelity's Wise Origin Bitcoin Fund (FBTC) have attracted $16.6 billion and $8.9 billion since their launch five months ago. However, Vanguard, which doesn't offer Bitcoin ETFs, leads with $102.8 billion in total ETF inflows in 2024. BlackRock's IBIT recently overtook the Grayscale Bitcoin Trust as the world's largest spot Bitcoin ETF, holding over $20 billion in Bitcoin.