BlackRock’s spot bitcoin exchange-traded fund (ETF), IBIT, has crossed 800,000 BTC in assets under management (AUM), cementing its position as the largest bitcoin fund in the world.
The milestone, reached on Wednesday, reflects $97 billion in AUM — achieved less than two years after IBIT began trading in January 2024. The fund saw $426 million in net inflows on October 8 alone, equivalent to roughly 3,510 BTC, pushing its total holdings to around 802,257 BTC, according to the latest disclosures.
That represents 3.8% of bitcoin’s fixed 21 million supply, underscoring BlackRock’s growing footprint in the digital asset market.
A Rapid Rise in Bitcoin Exposure
The pace of accumulation places BlackRock well ahead of MicroStrategy, which holds approximately 640,031 BTC, or 3.1% of the total supply. For comparison, MicroStrategy’s bitcoin holdings are valued near $78 billion, while BlackRock’s ETF now commands a significantly larger share through client investments.
The surge comes amid a sustained run of inflows into U.S. spot bitcoin ETFs. On Wednesday alone, the combined U.S. funds brought in $440 million, marking an eight-day streak totaling more than $5.7 billion, data shows.
Of that, IBIT accounted for more than $4.1 billion in the past week, highlighting its dominance in the sector.
“The eight-day streak of ETF inflows underscores persistent structural demand,” said Timothy Misir, Head of Research at BRN, in a comment. “Corporate treasury participation continues to expand, adding ballast to bitcoin’s narrative as a strategic reserve asset.”
Record-Breaking Momentum
According to Bloomberg ETF analyst Eric Balchunas, IBIT led all ETFs — not just crypto — in weekly flows with $3.5 billion, representing about 10% of all U.S. ETF inflows. “Even GBTC took in cash this week,” Balchunas wrote on X (formerly Twitter), describing the ETF market as being in “two steps forward mode.”
$IBIT is #1 in weekly flows among all ETFs w/ $3.5b which is 10% of all net flows into ETFs. Also notable is the rest of the 11 OG spot btc ETFs all took in cash in past week, even $GBTC somehow, that's how hungry the fish are. Two steps forward mode. Enjoy while it lasts. pic.twitter.com/iNrcgiRVHV
— Eric Balchunas (@EricBalchunas) October 8, 2025
On Monday, bitcoin ETFs recorded their largest daily haul since the pro-crypto U.S. presidential election last November, pulling in $1.21 billion.
Since launching, U.S. spot bitcoin ETFs have collectively attracted nearly $63 billion, though IBIT alone has brought in $65 billion in gross inflows — offset slightly by outflows from Grayscale’s converted GBTC fund.
“Spot BTC ETFs are on an all-time heater,” noted Nate Geraci, President of NovaDius Wealth Management. “They’ve taken in $5.3 billion over the past seven trading days. People once thought the whole category would cap at $5 billion total.”
Spot btc ETFs on an all-time heater…
— Nate Geraci (@NateGeraci) October 8, 2025
Have taken in absurd *$5.3bil* over past 7 trading days.
$2bil just over past two days.
I remember when people thought entire category would top out at $5bil total assets.
BlackRock’s ETF Breaks Records
IBIT’s growth has been extraordinary. The fund surpassed 500,000 BTC in December 2024, becoming one of the top three fastest-growing ETFs in U.S. history.
In an interview earlier this year, BlackRock CEO Larry Fink called IBIT “the fastest-growing ETF ever,” expressing surprise at how quickly both investor appetite and bitcoin’s price had surged.
Bitcoin, which traded near $69,000 in March, has since rallied roughly 76%, currently hovering around $121,500, according to BTC price index.
