BlackRock's iShares Bitcoin Trust (IBIT) is the undisputed leader in the spot Bitcoin ETF market. The fund holds approximately $47.5 billion in assets under management, representing about 61% of the total $78 billion in US spot Bitcoin ETFs.
Since its launch in January 2024, IBIT has attracted between $50 billion and $63 billion in net inflows. This rapid growth has established it as the dominant vehicle for institutional exposure to Bitcoin.
BlackRock's established relationships with wealth managers, pension funds, and sovereign wealth funds provided IBIT with access to capital that crypto-native firms could not easily replicate. This institutional capital has proven remarkably sticky, making the Bitcoin ETF a significant revenue driver for the world's largest asset manager.
The overall US spot Bitcoin ETF market now holds over 1.2 million BTC, representing about 5.77% of Bitcoin's entire circulating supply. This concentration creates a structural dynamic for the market.
While Fidelity's FBTC remains a credible alternative, the market is heavily concentrated. A potential risk is that a major market shock forcing significant redemptions across multiple ETFs could amplify selling pressure on Bitcoin's spot market.