A broader measure from BitcoinTreasuries data, tracking 254 entities, shows an even higher tally of 3,902,128 BTC (18.58% of supply) as of May 28 . When centralized exchanges are included, a Gemini and Glassnode report estimates that centralized entities now control close to 31% of the circulating supply, or over 6.1 million BTC . This rapid accumulation has been a decade in the making, with institutional holdings surging 924% over the past ten years .

Who Owns Bitcoin: The Breakdown

The institutional landscape is dominated by spot ETFs and public companies, which have been the primary engines of growth since U.S. regulators approved spot Bitcoin ETFs in January 2024. The table below breaks down the latest data from Bitbo's live treasury tracker as of May 31, 2026 .

It is worth noting that data sources vary slightly. Crypto analyst Cam estimated ETF holdings at a lower ~1.32 million BTC, which likely reflects a narrower definition that excludes certain non-U.S. or trust-based products .

The Largest Players: IBIT vs. Strategy

The race for the title of largest Bitcoin holder has narrowed to a near dead heat between an ETF giant and a corporate treasury pioneer.

• BlackRock’s iShares Bitcoin Trust (IBIT) is the single largest entity, holding ~821,513 BTC worth approximately $64.6 billion, representing nearly 3.9% of total supply .
• Strategy (formerly MicroStrategy) follows with an aggressively accumulated treasury of ~818,334 BTC, though with a significantly lower cost basis of around $13.5 billion . Other sources cite Strategy's holdings at up to 843,738 BTC, depending on the timing of its latest purchases .

Other major institutional holders include :

• Grayscale Bitcoin Trust (GBTC): ~218,000 BTC
• Fidelity Wise Origin Bitcoin Fund (FBTC): ~190,330 BTC
• U.S. Government: 328,372 BTC, primarily from seized assets
• Metaplanet: ~40,177 BTC
• Twenty One Capital (XXI): ~43,513 BTC
• MARA Holdings (formerly Marathon Digital): ~38,689 BTC

The concentration is notable: the top ten entities by BTC holdings now collectively control over 25% of the total supply .

The May Reversal: $2.8 Billion ETF Exodus

Despite the impressive accumulation figures, May 2026 delivered a jarring reversal in institutional flows that has yet to be fully reconciled.

After attracting $3.29 billion in net inflows over March and April — including a standout $2.44 billion in April alone — spot Bitcoin ETFs abruptly reversed course in mid-May . The sell-off was swift and sustained:

• A $1 billion weekly outflow for the week ending May 15 snapped a six-week inflow streak .
• By May 28, the outflow streak had extended to nine consecutive trading days totaling $2.8 billion, pushing year-to-date ETF flows into negative territory for the first time in months .
• The seven-day simple moving average of net flows cratered to -$88 million per day, the weakest reading since mid-February .
• The worst single day occurred on Wednesday of that week, with $733.43 million in outflows, including $527.84 million from BlackRock’s IBIT alone .

This is not a story of uniform retreat. JPMorgan increased its Bitcoin ETF holdings by 175% in Q1 2026, accumulating 8.3 million shares, even as it appeared to trim its position slightly in May . Meanwhile, long-term holder (LTH) supply remains anchored at 15.8 million BTC, indicating that the vast majority of the 2024–2026 buyer base is not distributing its coins .

The overall cumulative picture remains formidable: since their January 2024 launch, U.S. spot Bitcoin ETFs have attracted roughly $58 billion in net inflows . The May outflow episode, while sharp, has so far only trimmed a small fraction of those historic gains.

The $1.29B IBIT Dark Pool Trade: A Litmus Test for Maturity

On May 26, 2026, at 10:30 a.m. ET, a single dark pool transaction crossed Nasdaq’s off-exchange systems that instantly became the most dissected trade in crypto ETF history: 29.2 million shares of BlackRock’s IBIT, valued at $1.29 billion, executed at approximately $43.16 per share .

The trade was flagged by Galaxy Research’s Alex Thorn as the largest IBIT block trade he had ever seen, and it was later confirmed by Bloomberg ETF analysts James Seyffart and Eric Balchunas . The seller’s identity remains unknown.

What makes this trade historically significant is not its size, but the market’s reaction. Most sources report that Bitcoin’s spot price remained largely stable, with IBIT closing slightly up on the day . Some reports noted a brief ~2% dip, but there was no cascading liquidation or disorderly price action . Bloomberg’s Eric Balchunas summarized the event by stating the market “absorbed it well” .

The contrasting interpretations of this event capture the core debate about institutional Bitcoin today:

• A sign of maturity: The ability to quietly execute a $1.3 billion block via a dark pool without disrupting spot markets proves that Bitcoin’s liquidity infrastructure is now institutional-grade. A trade of this magnitude a year ago, analysts argue, would likely have caused significant market dislocation .
• A warning signal: The trade capped an eight-day ETF outflow streak and pushed two-week redemptions to $2.26 billion. It may represent a single institution rotating out of Bitcoin entirely, rather than a benign transfer .

Binance Research points to this trade as evidence that institutional Bitcoin exposure is increasingly being routed through regulated ETF rails rather than direct spot purchases, a shift that centralizes market access points but deepens overall liquidity .

Conclusion: A Market of Contradictions

The state of institutional Bitcoin ownership in late May 2026 is best described as robust but restless. The structural trend is undeniable: 3.88 million BTC are now locked in institutional treasuries and ETFs, a number that has grown over ninefold in a decade. Public company treasury adoption continues to spread, and long-term holder conviction appears unshaken.

Yet the near-term flow data and the historic IBIT dark pool trade suggest that some large players are taking chips off the table, even as others double down. The divergence between record holdings and record outflows is a paradox that will likely define the next chapter of Bitcoin’s institutionalization.

A broader measure from BitcoinTreasuries data, tracking 254 entities, shows an even higher tally of 3,902,128 BTC (18.58% of supply) as of May 28 . When centralized exchanges are included, a Gemini and Glassnode report estimates that centralized entities now control close to 31% of the circulating supply, or over 6.1 million BTC . This rapid accumulation has been a decade in the making, with institutional holdings surging 924% over the past ten years .

Who Owns Bitcoin: The Breakdown

The institutional landscape is dominated by spot ETFs and public companies, which have been the primary engines of growth since U.S. regulators approved spot Bitcoin ETFs in January 2024. The table below breaks down the latest data from Bitbo's live treasury tracker as of May 31, 2026 .

It is worth noting that data sources vary slightly. Crypto analyst Cam estimated ETF holdings at a lower ~1.32 million BTC, which likely reflects a narrower definition that excludes certain non-U.S. or trust-based products .

The Largest Players: IBIT vs. Strategy

The race for the title of largest Bitcoin holder has narrowed to a near dead heat between an ETF giant and a corporate treasury pioneer.

• BlackRock’s iShares Bitcoin Trust (IBIT) is the single largest entity, holding ~821,513 BTC worth approximately $64.6 billion, representing nearly 3.9% of total supply .
• Strategy (formerly MicroStrategy) follows with an aggressively accumulated treasury of ~818,334 BTC, though with a significantly lower cost basis of around $13.5 billion . Other sources cite Strategy's holdings at up to 843,738 BTC, depending on the timing of its latest purchases .

Other major institutional holders include :

• Grayscale Bitcoin Trust (GBTC): ~218,000 BTC
• Fidelity Wise Origin Bitcoin Fund (FBTC): ~190,330 BTC
• U.S. Government: 328,372 BTC, primarily from seized assets
• Metaplanet: ~40,177 BTC
• Twenty One Capital (XXI): ~43,513 BTC
• MARA Holdings (formerly Marathon Digital): ~38,689 BTC

The concentration is notable: the top ten entities by BTC holdings now collectively control over 25% of the total supply .

The May Reversal: $2.8 Billion ETF Exodus

Despite the impressive accumulation figures, May 2026 delivered a jarring reversal in institutional flows that has yet to be fully reconciled.

After attracting $3.29 billion in net inflows over March and April — including a standout $2.44 billion in April alone — spot Bitcoin ETFs abruptly reversed course in mid-May . The sell-off was swift and sustained:

• A $1 billion weekly outflow for the week ending May 15 snapped a six-week inflow streak .
• By May 28, the outflow streak had extended to nine consecutive trading days totaling $2.8 billion, pushing year-to-date ETF flows into negative territory for the first time in months .
• The seven-day simple moving average of net flows cratered to -$88 million per day, the weakest reading since mid-February .
• The worst single day occurred on Wednesday of that week, with $733.43 million in outflows, including $527.84 million from BlackRock’s IBIT alone .

This is not a story of uniform retreat. JPMorgan increased its Bitcoin ETF holdings by 175% in Q1 2026, accumulating 8.3 million shares, even as it appeared to trim its position slightly in May . Meanwhile, long-term holder (LTH) supply remains anchored at 15.8 million BTC, indicating that the vast majority of the 2024–2026 buyer base is not distributing its coins .

The overall cumulative picture remains formidable: since their January 2024 launch, U.S. spot Bitcoin ETFs have attracted roughly $58 billion in net inflows . The May outflow episode, while sharp, has so far only trimmed a small fraction of those historic gains.

The $1.29B IBIT Dark Pool Trade: A Litmus Test for Maturity

On May 26, 2026, at 10:30 a.m. ET, a single dark pool transaction crossed Nasdaq’s off-exchange systems that instantly became the most dissected trade in crypto ETF history: 29.2 million shares of BlackRock’s IBIT, valued at $1.29 billion, executed at approximately $43.16 per share .

The trade was flagged by Galaxy Research’s Alex Thorn as the largest IBIT block trade he had ever seen, and it was later confirmed by Bloomberg ETF analysts James Seyffart and Eric Balchunas . The seller’s identity remains unknown.

What makes this trade historically significant is not its size, but the market’s reaction. Most sources report that Bitcoin’s spot price remained largely stable, with IBIT closing slightly up on the day . Some reports noted a brief ~2% dip, but there was no cascading liquidation or disorderly price action . Bloomberg’s Eric Balchunas summarized the event by stating the market “absorbed it well” .

The contrasting interpretations of this event capture the core debate about institutional Bitcoin today:

• A sign of maturity: The ability to quietly execute a $1.3 billion block via a dark pool without disrupting spot markets proves that Bitcoin’s liquidity infrastructure is now institutional-grade. A trade of this magnitude a year ago, analysts argue, would likely have caused significant market dislocation .
• A warning signal: The trade capped an eight-day ETF outflow streak and pushed two-week redemptions to $2.26 billion. It may represent a single institution rotating out of Bitcoin entirely, rather than a benign transfer .

Binance Research points to this trade as evidence that institutional Bitcoin exposure is increasingly being routed through regulated ETF rails rather than direct spot purchases, a shift that centralizes market access points but deepens overall liquidity .

Conclusion: A Market of Contradictions

The state of institutional Bitcoin ownership in late May 2026 is best described as robust but restless. The structural trend is undeniable: 3.88 million BTC are now locked in institutional treasuries and ETFs, a number that has grown over ninefold in a decade. Public company treasury adoption continues to spread, and long-term holder conviction appears unshaken.

Yet the near-term flow data and the historic IBIT dark pool trade suggest that some large players are taking chips off the table, even as others double down. The divergence between record holdings and record outflows is a paradox that will likely define the next chapter of Bitcoin’s institutionalization.