BlackRock's Bitcoin ETFs have become the company's most profitable product line, according to Cristiano Castro, Director of Business Development in Brazil. The combined assets under management for BlackRock's U.S. IBIT and Brazil's IBIT39 have nearly reached $100 billion. The U.S. spot Bitcoin ETF, IBIT, launched in January 2024, surpassed $70 billion in assets within 341 days, holding over 3% of Bitcoin's supply. In October, its annualized management fee income was estimated at $245 million. BlackRock has also increased its holdings in its Bitcoin ETF, with its Strategic Income Opportunities Portfolio raising its IBIT position by 14%.