BlackRock, one of the world's largest asset managers, revealed in regulatory filings that its income and bond-focused funds invested in shares of its own Bitcoin exchange-traded fund (ETF) during the first quarter. The filings with the Securities and Exchange Commission showed that the Strategic Income Opportunities Fund (BSIIX) acquired $3.56 million worth of shares in the iShares Bitcoin Trust (IBIT), while the Strategic Global Bond Fund (MAWIX) bought $485,000 worth of IBIT.

It's important to note that the IBIT shares represent only a small fraction of the investment portfolios of BSIIX and MAWIX, which are valued at $37.4 billion and $776.4 million, respectively.

As of May 24, the iShares Bitcoin Trust held around $19.61 billion worth of Bitcoin, making it the second-largest holder of Bitcoin assets, just behind the Grayscale Bitcoin Trust (GBTC), which held $19.76 billion as of May 28. The global holdings of spot Bitcoin ETFs now exceed 1 million Bitcoin, with a total value of over $68 billion. This accounts for nearly 5.10% of the circulating supply of Bitcoin, which stands at over 19.7 million BTC, according to CoinMarketCap.

Recent Securities and Exchange Commission filings revealed that more than 600 investment firms in the United States have invested in spot Bitcoin ETFs since their launch in January. Notable institutions such as Morgan Stanley, JPMorgan, Wells Fargo, Royal Bank of Canada, BNP Paribas, UBS, as well as hedge funds like Millennium Management and Schonfeld Strategic Advisors. Among these firms, Millennium Management has emerged as the largest accumulator of spot Bitcoin ETFs, with $1.9 billion invested.