BlackRock’s bitcoin exchange-traded funds (ETFs) have become the company’s most profitable product line, according to Cristiano Castro, director of business development at BlackRock Brazil.
The figure is notable given that the company manages more than 1,400 ETFs worldwide and is the world’s largest asset manager with more than $13.4 trillion in assets under management.
Speaking to local media at the Blockchain Conference in São Paulo, Castro called the development “a big surprise” and said allocations in the firm’s bitcoin ETFs, including the US-based IBIT and Brazil’s IBIT39, had approached $100 billion.
“When we launched it, we were optimistic,” Castro said, “but we didn’t expect this scale.”
The US-listed IBIT spot bitcoin ETF, launched in January 2024, became the fastest in history to reach $70 billion in assets, in 341 days. That momentum has continued despite recent volatility in the price of bitcoin, with the ETF currently holding $70.7 billion in net assets according to data from SoSoValue.
Net inflows exceeded $52 billion in its first year, far outpacing all other ETFs launched in the last decade. IBIT also generated approximately $245 million in annual fees by October 2025.
IBIT’s rapid growth has been fueled by BlackRock’s global distribution network and a wave of institutional interest following US regulatory approval of spot bitcoin ETFs. It now holds more than 3% of the total bitcoin supply, and was followed by several BlackRock BTC-pegged products, including offshore ETPs.
Castro referred to recent fund outflows from bitcoin and said such a move is expected given the way retail investors tend to react to price drops. “ETFs are a very liquid and powerful tool. They are intended for people to manage flows,” he said.
BlackRock itself has been betting on its bitcoin ETF. Its Strategic Income Opportunities Portfolio has recently increased its holding in IBIT by 14%.
CoinDesk reached out to BlackRock but did not receive a response at the time of writing.
