Spot bitcoin ETFs shed $1.26 billion in worst week since late January as ether funds see 10-day outflow streak

U.S. spot bitcoin ETFs ended the week with roughly $1.26 billion in cumulative net outflows, the heaviest weekly drain since late January, capping a six-day outflow streak totaling $1.55 billion, according to SoSoValue data. 

The 12 U.S.-based funds lost a combined $648.6 million on Monday alone, when bitcoin slipped below $77,000 after President Trump's latest Iran threat, the largest single-day outflow since Jan. 29. "Key culprits [are] surging Treasury yields hitting 12-month highs, a stronger dollar, and geopolitical escalation," Andri Fauzan Adziima, research lead at Bitrue Research Institute, previously told The Block.

Outflows eased after Monday but never turned positive, with the funds shedding $331 million on Tuesday, $70.5 million on Wednesday, $100.8 million on Thursday, and $105.2 million on Friday, per the data.

Spot ether ETFs took a smaller dollar hit but have seen a longer outflow streak. The nine funds posted $216 million in combined outflows across the week, bringing their consecutive outflow run to 10 sessions, the category's most sustained outflow streak since March of 2025. 

That stretch has now pulled cumulative ether ETF net inflows down to $11.62 billion against $11.84 billion in net assets. That leaves the funds' net assets sitting just $223 million above their cumulative inflows. 

The asymmetry is sharper at the issuer level of certain funds. BlackRock's iShares Bitcoin Trust, which still leads the market in assets under management (AUM), closed Friday with $61.1 billion in net assets against $64.8 billion in cumulative net inflows, putting current market value roughly $3.7 billion below the dollars investors have put in. Fidelity's FBTC, by contrast, still carries a roughly $3.2 billion cushion of net assets over cumulative inflows.

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The week's flow data landed in a market that hadn't made significant moves all week. Bitcoin opened Friday around $77,550 and ether around $2,130, with both assets holding tight ranges since Monday's open. Bitcoin's intraweek band came in under $1,000, and ether barely moved from Monday to Friday, per The Block's Ethereum Price page. However, ether has dropped about 3.3% over the past 24 hours, a significant move that came after Friday's ETF market close.

The structural backdrop has apparently been deteriorating for weeks. A May 14 Bitfinex report cited by The Block found that corporate treasury buyers pulled back roughly 80% in purchase volume month-over-month, leaving ETFs as one of the only institutional demand channels still active.

With that channel now also in retreat, the spot bid has thinned, visibly. Aggregate cumulative volume delta on bitcoin's spot order books ran negative for nine consecutive sessions through May 19, the longest sustained net-selling stretch of 2026, according to a Nexo note cited by The Block.

Despite the week's losses, spot bitcoin ETFs still hold $57.1 billion in cumulative net inflows and $98.9 billion in total net assets across all 12 funds, with IBIT alone accounting for 4% of bitcoin's circulating supply.