Bitcoin ETFs are now BlackRock’s top revenue source, Exec says. The firm's US-listed spot bitcoin ETF IBIT, launched in January 2024, reached $70 billion in assets in record time and has generated hundreds of millions in fees. IBIT now holds over 3% of bitcoin's total supply, and BlackRock's own Strategic Income Opportunities Portfolio has increased its stake in IBIT by 14%, betting on the ETF's continued growth.