[markets]
On May 31 at 7:41 PM UTC, NYDIG published a research note concluding that a $1.26 billion block sale of BlackRock's iShares Bitcoin Trust (IBIT) earlier in the week was most likely a large investor racing for the exit — not a hedge-fund trade unwind.
The transaction itself took place on May 26: 29.21 million IBIT shares changed hands off-exchange at $43.16 per share, against a market price of $44.17. That $1.01 gap — a 2.3% concession — translated to roughly $29.5 million in execution costs. The trade cleared through the FINRA/Nasdaq TRF Carteret facility, the standard venue for privately negotiated off-exchange blocks.
Some traders had floated the basis-trade theory: that a fund holding spot IBIT while shorting CME bitcoin futures might have been unwinding both legs simultaneously. NYDIG's Greg Cipolaro, the firm's global head of research, shot that down. The IBIT position was the equivalent of roughly 3,700 CME bitcoin futures contracts. During the minute the block executed, only 91 contracts traded — no unusual futures spike. And the 2.3% discount alone would have gutted the returns a basis trade would have been chasing. "The size of the trade, the 2.3% execution discount, the absence of corresponding CME futures activity, and the limited universe of potential sellers collectively weigh against the view that the transaction represented a contemporaneous basis-trade unwind," Cipolaro wrote.
Identity remains unknown. NYDIG noted that the position exceeded the reported holdings of every disclosed IBIT investor in recent 13F filings, making the seller untraceable from public filings. IBIT recorded roughly $720 million in net redemptions across May 26 and May 27, but ETF flow data cannot be used to directly link redemptions to a specific block transaction or identify who sold. Public data, the firm said, cannot determine whether the sale was driven by investor redemptions, risk-management constraints, or a discretionary decision to reduce exposure.
The block landed in a hostile window for Bitcoin ETFs. According to SoSoValue, U.S. spot Bitcoin ETFs posted net outflows on every trading day from May 15 through May 29, with total AUM falling from $107.75 billion on May 14 to $94.17 billion by May 29. Bitcoin is down 16% year-to-date and has dropped to the 13th-largest asset globally as capital continues rotating toward AI equities and commodities.
What NYDIG's analysis makes clear is that someone with a position too large to unwind gradually accepted a $29.5 million haircut to exit all at once. The why remains open.