An institutional investor unloaded $1.26 billion worth of BlackRock's iShares Bitcoin Trust (IBIT) on Monday morning in what's being called the largest single off-exchange trade in the history of U.S. spot Bitcoin ETFs. The block of 29.21 million shares changed hands at 10:30 a.m. Eastern via a privately negotiated transaction reported to FINRA/Nasdaq TRF Carteret. The seller accepted a 2.3% haircut — $43.16 per share versus the market price of $44.17 — and paid nearly $30 million in execution costs for the privilege of moving fast.
How the trade went down
The deal used an Intermarket Sweep Order designation and a Reg NMS trade-through exemption. That's a technical way of saying the seller cared more about speed than getting the best possible price. The broker handling the order swept multiple trading centers simultaneously and executed the block at a single discounted price, bypassing the normal requirement to route to the market displaying the best quote. It's a tool usually reserved for big institutional moves where time matters more than a few cents.
Why it wasn't a basis trade unwind
Some market watchers initially guessed this was a basis trade — a hedge unwind where someone closes a long ETF/short futures position. NYDIG's analysis killed that theory fast. During the minute the ETF block traded, only 91 CME Bitcoin futures contracts changed hands. A genuine basis unwind would have produced a spike in futures volume. That didn't happen. NYDIG concluded the block was a straight cash sale of the ETF shares, not a paired trade.
The cost of speed
Thirty million dollars in execution costs. That's the price tag for walking away from the market price. The 2.3% discount is steep by any standard for a liquid ETF, but the seller clearly wanted certainty. A large sell order hitting the open market would have moved the price far more and taken hours — or days — to fill. The off-exchange block let the seller dump the entire position in one shot. The broker presumably matched it against a buyer or buyers willing to take the other side at a discount.
Liquidity testing ahead of the block
Something was brewing before the main event. Between 10:16 a.m. and 10:28 a.m., IBIT trading volume ran at three to four times normal levels. That suggests the broker was testing liquidity, pinging the market to gauge how much depth was available before committing the full block. Once the test confirmed enough appetite, the big trade went through.
What the trade reveals about ETF depth
The $1.26 billion block exceeded the total IBIT holdings disclosed by all 13F filers in Q1 2026 — excluding authorized participants and market makers. That's a reminder that the visible holder base for Bitcoin ETFs is smaller than the headline AUM suggests. A single big player can move more shares than the entire reported institutional ownership combined. Who was the seller? That detail wasn't disclosed. The trade was reported to a trade reporting facility, so the counterparties are anonymous unless they choose to speak. For now, the market knows the size, the cost, and the timing — but not the name.
