iShares Bitcoin Trust ETF surpasses Fidelity in assets under management

BlackRock’s iShares Bitcoin Trust ETF has turned what was once a competitive race into something closer to a victory lap. As of June 26, 2025, IBIT reported approximately $44.87 billion in assets under management, holding 742,870 Bitcoin on behalf of its investors. Fidelity’s Wise Origin Bitcoin Fund, the product most often cited as its nearest competitor, sits somewhere between $10.4 billion and $13.5 billion in AUM. That is not a close race.

Both products launched in January 2024, after the US Securities and Exchange Commission approved spot Bitcoin ETFs, a moment that reshaped how institutional capital could access crypto markets.

How IBIT got here

IBIT reached $10 billion in AUM faster than any prior ETF after its launch, a milestone that made clear this product was not a niche curiosity. For context, most ETFs spend years trying to cross $1 billion, a threshold sometimes called the point where a fund becomes financially viable for its issuer.

Liquidity matters enormously in ETF investing, and this is where IBIT’s scale creates a self-reinforcing advantage. Deeper trading volumes mean tighter bid-ask spreads, which means lower real-world costs for investors executing large orders. Once a fund becomes the liquidity leader, it tends to stay that way, because everyone who cares about execution quality migrates toward the most liquid option.

The custody arrangements for the two funds differ. Coinbase Custody handles Bitcoin for IBIT, while Fidelity Digital Assets manages custody for FBTC. Both funds charge an identical expense ratio of 0.25%. That means cost is not a differentiator here.

What this means for the Bitcoin ETF market

IBIT’s 742,870 Bitcoin represents a meaningful concentration of supply held in a single product. As spot Bitcoin ETFs collectively accumulate holdings, the share of circulating Bitcoin locked in regulated vehicles grows.

For traders focused on execution, IBIT’s liquidity advantage has practical consequences. Tighter spreads on a fund tracking a volatile asset like Bitcoin can meaningfully affect returns over time, particularly for investors who trade actively or who need to enter and exit positions quickly.