Sophia Bennett
Crypto Analyst
The numbers coming out of BlackRock's Bitcoin ETF on Wednesday were historic, and not in a good way.
BlackRock's iShares Bitcoin Trust shed $527.84 million on Wednesday, the second‑largest single‑day net outflow since the fund launched in January 2024.
How close did it come to an all‑time record? Uncomfortably close. The figure missed IBIT's record outflow of $528.3 million, set on January 30, by less than half a million dollars.
For a fund that holds roughly $59 billion in assets and accounts for close to 4% of Bitcoin's entire supply, a withdrawal of this scale in a single session is a meaningful signal.
Not Just BlackRock, The Whole Market Is Bleeding
Wednesday's damage wasn't limited to one fund. The 11 U.S.-listed spot bitcoin ETFs lost a combined $733.43 million on Wednesday, with Fidelity's FBTC shedding $60.30 million and Grayscale's GBTC losing $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 The complex has now posted outflows for several consecutive sessions, with more than $2 billion withdrawn over the past two weeks.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 pattern is becoming hard to dismiss as noise. This is a sustained, institutional‑level exit from Bitcoin exposure.
Iran Strikes Triggered the Sell‑Off
The catalyst was geopolitical, and sudden. The selling landed on the same day bitcoin broke below $73,000, after U.S. airstrikes on an Iranian military site near the Strait of Hormuz reignited a conflict markets had started to price out.
When that news broke, risk assets sold off fast. Bitcoin traded at $72,978 in Asian hours Thursday, down 3.4% over 24 hours. The ETF outflows and the price drop fed each other, with redemptions forcing BlackRock and other issuers to sell the underlying bitcoin to settle investor exits.
It's a brutal feedback loop, falling prices trigger redemptions, which force more selling, which pushes prices lower.
Tuesday's Dark Pool Sale Set the Stage
Wednesday's outflow didn't arrive out of nowhere. The day before had already flashed serious warning signs. On Tuesday, a single investor sold $1.29 billion of IBIT shares in one dark‑pool block trade.
A dark‑pool transaction allows large investors to move enormous positions without alerting the open market. That block sale was not the same as a net outflow, since buyers can step in to absorb the volume, and IBIT's actual net redemptions on Tuesday came to $192.44 million. But the two events together point to institutional players trimming bitcoin exposure as the macro backdrop turned.
May Has Flipped From Buying to Selling
The shift in monthly momentum makes the picture even more concerning. ETF accumulation across the year had already thinned to a net of around 4,500 BTC, and May flipped from the steady buying of March and April into distribution. Bitcoin has dropped from above $82,000 on May 6 to under $73,000 now, and the ETF channel that drove the 2025 rally has spent the month pulling money the other way.
Has This Happened Before?
It has, and Bitcoin recovered each time. IBIT has gone through extended outflow streaks before during this cycle without a permanent reversal, with money returning each time the macro picture cleared.
The question now is whether the Iran situation stabilises quickly enough to bring institutional buyers back before the damage deepens further. Right now, the market isn't waiting around to find out.