Someone Just Sold $1.29 Billion of BlackRock’s Bitcoin ETF in a Single Dark-Pool Trade

An unknown investor sold $1.29 billion worth of BlackRock’s iShares Bitcoin Trust in a single dark-pool block trade on Tuesday morning. The 29.2 million-share sale was the biggest IBIT block trade Galaxy Digital head of research Alex Thorn said he had seen.

The trade hit at 10:30 a.m. ET while U.S. spot Bitcoin ETFs were already deep in a week-long outflow streak.

massive $1.289 billion IBIT block sale by unknown party through dark pool at 10:30am today, biggest such trade i've ever seen pic.twitter.com/9qGDqkfCbu

— Alex Thorn (@intangiblecoins) May 26, 2026

A dark pool is a private exchange where large institutional trades execute away from the public order book. The purpose is to avoid moving the market with a massive sell order.

In this case, the size still got noticed fast.

Bloomberg ETF analyst Eric Balchunas confirmed the trade and pointed out that the market absorbed the block without IBIT’s price collapsing on the day.

Confirmed.. 29 million share trade ($1.3b) of $IBIT executed at 1030am this morning.

This screen shows all the IBIT trades today by size and you can see one of these is not like the others. Price unchanged today so mkt absorbed it well. https://t.co/Otew0DWa3F pic.twitter.com/jZcoKez74K

— Eric Balchunas (@EricBalchunas) May 26, 2026

Bitcoin itself did move. Cointelegraph reported that BTC fell from roughly $77,875 to $76,720 in a ten-minute window after the trade time cited by analysts.

That is a fast $1,100 drop on a coin already sliding from above $82,000 earlier in May.

The block sale landed in the middle of a broader fund-flow reversal.

CoinDesk reported the latest fund-flow backdrop this way:

According to CoinDesk: The central market event was an unknown investor sold more than a billion dollars worth of BlackRock IBIT shares in one dark-pool block trade during Tuesday trading. The report says the transaction came while U.S. spot Bitcoin ETFs were already in a broad outflow stretch, with about $334 million leaving the 11 funds in the latest session and $2.26 billion withdrawn over two weeks.

CoinDesk also noted that IBIT itself processed roughly $192.44 million of net redemptions for the day, so the huge block trade landed inside a real fund-flow reversal rather than a clean risk-on market. CoinDesk reported on May 27, 2026 that an unknown investor executed a single $1.29 billion block sale of BlackRock’s IBIT Bitcoin ETF in a dark pool during Tuesday trading.

CoinDesk reported that the trade involved BlackRock’s iShares Bitcoin Trust, ticker IBIT, and that Galaxy Digital head of research Alex Thorn called it the biggest such trade he had seen.

The Block independently confirmed the session at $333.7 million in net outflows. Its fund-level breakdown put Fidelity’s FBTC at $57.7 million of outflows and Grayscale’s GBTC at $41.3 million, with additional negative flows at Grayscale Bitcoin Mini Trust and Bitwise BITB.

According to The Block: U.S. spot Bitcoin ETFs saw $333.7 million of net outflows on Tuesday, extending the negative streak to seven trading days. Its fund-flow breakdown put BlackRock IBIT at $192.4 million of outflows, Fidelity FBTC at $57.7 million, Grayscale GBTC at $41.3 million, and additional negative flows at Grayscale Bitcoin Mini Trust and Bitwise BITB.

The Block also reported that the past seven trading days had produced $1.88 billion of Bitcoin ETF outflows and that the streak was the longest negative run since December 2025. The Block reported the same Tuesday ETF-flow session at $333.7 million in net outflows, led by $192.4 million from BlackRock IBIT, with Fidelity FBTC and Grayscale GBTC also negative.

The Block reported that the seven-day Bitcoin ETF outflow streak was the longest negative-flow streak since December 2025. Cointelegraph reported that the trade involved 29.2 million IBIT shares and that Bitcoin fell from about $77,875 to $76,720 in a ten-minute window after the trade time cited by analysts.

The year-to-date picture adds context. A separate CoinDesk report citing Swissblock data showed U.S. spot Bitcoin ETFs had absorbed only about 4,500 BTC net so far in 2026, with May flipping from accumulation into distribution.

That is a thin cushion. ETF demand was one of the main channels absorbing sell pressure from miners, long-term holders, and short-term traders through March and April.

When that bid dries up, Bitcoin’s price has to find buyers somewhere else.

$BTC Clean retest of the April 2025 lows with a decent bounce so far.

But the level to break for continuation remains the low $80Ks.

Below $74K I'd say bears are back in control on the low to mid timeframe as well.

So from here we'll just wait and see which side breaks first… pic.twitter.com/pQLg4XVEHt

— Daan Crypto Trades (@DaanCrypto) May 26, 2026

A $1.29 billion block trade through a dark pool does not automatically mean panic selling. Someone also bought those 29.2 million shares on the other side of the trade.

Balchunas noted the absorption. The real pressure signal is the broader seven-day outflow streak and the speed at which May’s ETF flows have deteriorated.

Bitcoin remains the largest crypto asset by market cap at above $1.5 trillion. IBIT is its biggest institutional on-ramp.

When the plumbing behind that on-ramp starts running in reverse for a full week, it tells you something about where big money’s conviction sits right now. Buyers will have to step back in soon, or this flow picture gets worse before it gets better.

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