Whale Sells $1.26B BlackRock Bitcoin ETF Block at $43.16

On May 26 an institutional investor executed a $1.26 billion off-exchange sale of BlackRock’s iShares Bitcoin Trust (IBIT), disposing of 29.21 million shares at $43.16 a share. The execution price represented a 2.3% discount to the prevailing market price at the time, an estimated $29.5 million in execution cost.

The trade was printed to the FINRA/Nasdaq trade reporting facility at 10:30 a.m. Eastern after a brief period of elevated on-exchange activity. IBIT had risen from $43.81 to an intraday high of $44.24 between 10:16 a.m. and 10:28 a.m., with trading volume in that window three to four times normal levels. The market price at the second the block crossed was $44.17.

Regulatory codes attached to the print show the transaction used an Intermarket Sweep Order designation and a Reg NMS trade-through exemption. Those designations let an executing broker prioritize immediate, unified execution over securing the best displayed quote across multiple public venues, subject to other execution obligations.

Analysis by NYDIG lists three factors that argue against the sale being a routine basis-trade unwind. First, accepting a 230-basis-point loss on the spot leg would largely erase the narrow yield such arbitrage strategies target. Second, the use of sweep orders and a large block discount is inconsistent with typical behavior of a delta-neutral arbitrage desk. Third, the futures market did not show the activity that would match an arbitrage unwind of this size: the 29.21 million-share block equates to roughly 18,500 Bitcoin, which would require buying back about 3,700 CME Bitcoin futures contracts; only 91 futures contracts traded at the minute the block crossed and about 1,000 contracts traded in the surrounding half hour.

The counterparty that bought the block likely held the shares in inventory rather than immediately redeeming them with the issuer. IBIT’s net asset value closed at $42.95 on the trade date and fell to $42.43 the following day, both below the $43.16 block price, which would have created an immediate loss if the buyer had redeemed at the issuer level. The block also exceeded the combined holdings of all disclosed 13F investors in Q1 2026, excluding authorized participants and market makers.

The transaction occurred amid declining demand for U.S. spot Bitcoin ETFs. The funds entered the May 26 session on a six-day run of outflows that totaled $1.55 billion, with IBIT accounting for about $1.1 billion of that withdrawal. For the full month of May, U.S. spot Bitcoin ETFs recorded roughly $2.4 billion in outflows, reducing assets under management in the category from above $100 billion to about $94.17 billion.

An ETF analyst described the market reaction as having absorbed the sale well. The identity and motive of the seller remain unknown; off-exchange reporting rules and the private nature of the block trade prevent determining whether the investor was forced to exit or chose a rapid liquidation for other reasons.