Spot Bitcoin ETFs Record $139 Million in Net Inflows as Ethereum Funds Extend Outflow Streak
Spot Bitcoin exchange-traded funds recorded $139.54 million in net inflows on May 15, equivalent to 1,761 BTC at prevailing prices, while spot Ethereum ETFs posted a fourth consecutive day of net outflows totaling $5.21 million, or 2,350 ETH. BlackRock‘s iShares Bitcoin Trust absorbed $144 million on its own, more than covering the aggregate inflow across the full Bitcoin ETF category. The divergence marks the widest single-day gap between Bitcoin and Ethereum institutional fund flows since the two product categories began trading alongside each other in mid-2024.
The Flow Numbers in Detail
Bitcoin (BTC) held near $79,160 on May 15 as the ETF inflow data was published by Blockchain News.
BlackRock’s IBIT fund (IBIT) drove the bulk of that day’s positive flow, taking in $144 million independently. Other Bitcoin ETF issuers saw modest mixed results that netted to a positive aggregate figure. Ethereum (ETH) ETFs have now shed assets for four straight sessions, with cumulative outflows over that period exceeding $20 million.
The pattern suggests institutional allocators are maintaining Bitcoin exposure while reducing or rotating out of Ethereum-linked products in the near term.
Also Read: Bitcoin Exchange Supply Falls to an 8-Year Low as Investors Withdraw Coins to Cold Storage
Background
Spot Bitcoin ETFs launched in the United States in January 2024 after a decade of SEC rejections, immediately attracting billions in institutional capital. Spot Ethereum ETFs followed in July 2024 but drew smaller flows from the start, partly because Ethereum’s staking yield is excluded from the U.S.
ETF wrapper, reducing its appeal relative to direct on-chain holdings. Bitcoin ETF total assets under management crossed $100 billion in early 2025 and have held above that threshold through most of the year.
The May 15 inflow extends a positive run that has now seen net weekly inflows into Bitcoin ETFs for the past three consecutive weeks, according to flow tracking published by Blockchain News.
Also Read: Interactive Brokers Expands Cryptocurrency Futures Access Through Coinbase Derivatives
What to Watch
Bitcoin price sits roughly 21% below its all-time high, and ETF inflows at this range have historically preceded sustained price recovery periods. Whether Ethereum ETF outflows reverse depends partly on whether the SEC approves in-kind redemption or staking features for Ethereum fund structures, a decision that remains pending.
The next key data point is weekly flow totals, with three straight positive weeks for Bitcoin ETFs suggesting durable institutional appetite even as the broader market trades cautiously amid macro uncertainty.
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