BlackRock's spot Bitcoin ETF has attracted significant institutional interest, with 414 holders, a rare feat for new ETFs. In the first quarter, top holders include Millennium Management with $2 billion, Susquehanna with $1.1 billion, and Horizon Kinetics with $989 million. US spot Bitcoin ETFs collectively absorbed 548,556 BTC worth $36 billion in 128 days. Institutional investments in Bitcoin ETFs reached $37 billion in four months, with major players like JPMorgan, Wells Fargo, and Morgan Stanley participating. Digital asset investment products saw $932 million in inflows last week, with Bitcoin leading at $942 million, while Ethereum experienced $23 million in outflows. BlackRock's Bitcoin ETF alone surpassed $1.2 billion in trading volume, with $67 million in inflows on May 20. Grayscale’s Bitcoin ETF weekly flows turned green for the first time ever and posted a fourth consecutive positive day with $9 million in inflows. Bitwise bought 346 BTC worth $24 million.