BlackRock's iShares Bitcoin Trust shed $527.84 million on Wednesday, May 28, 2026 — the second-largest single-day net outflow since the fund launched in January 2024, missing the all-time record by less than half a million dollars.
The record still stands at $528.3 million, set on January 30, 2024. Wednesday's draw came within roughly $500,000 of matching it. IBIT holds approximately $59 billion in assets and accounts for close to 4% of bitcoin's total supply, making it the largest single vehicle for institutional bitcoin exposure. Both figures are per SoSoValue.
The IBIT outflow was not isolated. All 11 U.S.-listed spot bitcoin ETFs combined to shed $733.43 million on Wednesday, per SoSoValue's aggregate tracker. Fidelity's FBTC lost $60.30 million and Grayscale's GBTC dropped $104.76 million alongside the IBIT draw. The complex has now posted outflows for several consecutive sessions, with more than $2 billion withdrawn over the past two weeks.
The trigger was geopolitical. U.S. airstrikes on an Iranian military site near the Strait of Hormuz reignited risk fears that markets had begun to price out. Bitcoin dropped to $72,978 in Asian hours Thursday, down 3.4% over 24 hours. Redemptions forced issuers to sell underlying bitcoin to settle investor exits, feeding the price decline.
Wednesday's outflow came one day after a separate move in the fund drew attention. On Tuesday, a single investor sold $1.29 billion of IBIT shares in a dark-pool block trade, as CoinDesk reported. A dark-pool transaction is a privately negotiated trade that lets large players move size without signaling the broader market. That block sale was not a net outflow — buyers absorbed the volume — and IBIT's actual net redemptions on Tuesday came to $192.44 million. The two events together point to institutional players actively trimming bitcoin exposure as the macro backdrop shifted.
The flow data has been deteriorating for weeks. Year-to-date ETF accumulation had already thinned to a net of roughly 4,500 BTC, per CoinDesk's May 27 report, after March and April saw steady buying. Bitcoin has dropped from above $82,000 on May 6 to under $73,000. The ETF channel that anchored the 2025 bull run is now running in reverse.
Whether Wednesday's draw marks tactical de-risking around the Hormuz headlines or the start of a deeper institutional pullback will depend on what happens once the Middle East situation stabilizes. What is already clear: the magnitude of a single-day draw that nearly matched the all-time record is not routine rebalancing. It is the institutional hand showing.