Bitcoin dropped sharply from roughly $78,000 to $75,677 on Tuesday after a reported $1.3 billion dark pool dump tied to BlackRock’s iShares Bitcoin Trust (IBIT) rattled markets and triggered fears of major institutional selling.

The block trade, estimated at 29 million shares, crossed around 10:30 a.m. at approximately $43 per share, as confirmed by Bloomberg ETF analyst Eric Balchunas. Traders said the single transaction exceeded IBIT’s average daily volume on its own and represented one of the largest institutional IBIT prints tracked since the ETF launched.

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

Dark pool tracking accounts linked the transaction to immediate weakness in Bitcoin price action, with speculation mounting that the trade could eventually show up as the largest one-day Bitcoin ETF outflow ever recorded.

Even amid the heavy selling pressure, options flow indicates that some institutional traders remain constructive on the market’s long-term outlook.

What is a dark pool?

Dark pools are off-exchange trading platforms designed for large institutional transactions that investors may not want exposed to the public market immediately. They are commonly used by banks, hedge funds, and large asset managers to execute oversized trades without causing sharp price swings before the order is completed.

IBIT’s rise to institutional heavyweight

IBIT launched on January 5, 2024, and has since grown into the dominant spot Bitcoin ETF with approximately $61 billion in assets under management as of May 26, according to its disclosure.

IBIT recorded around $192 million in net outflows on Tuesday, while US-listed spot Bitcoin ETFs bled nearly $334 million, per Farside Investors.