BlackRock's iShares Bitcoin Trust ETF (IBIT) has become the asset management giant's most profitable exchange-traded fund, just 21 months after launch, surpassing products that have been generating revenue for more than two decades. IBIT is sitting "a hair away from $100 billion" in assets under management, and now generates approximately$244.5 million in annual revenue for BlackRock, Bloomberg analyst Eric Balchunas tweeted Monday. "Check out the ages of the rest of the Top 10. Absurd," Balchunas wro ...