According to official documents from the US SEC, BlackRock has submitted a file to the SEC requesting to add exposure to a Bitcoin ETF to its Strategic Income Opportunities Fund (BSIIX) portfolio.The file states: "The Fund may purchase shares of exchange-traded products (ETPs) that are designed to track the price and performance of bitcoin, such as the bitcoin ETP shares issued and managed by affiliated companies of BlackRock."It is reported that the BSIIX fund has a total size of $36.5 billion, and as of March 1, the net asset value of its share class totaled $24.2 billion. The fund typically invests in fixed income securities and other market sectors under specific conditions.