U.S. bitcoin ETFs recorded their largest single-day inflows in more than a month on December 17, 2025, a move that coincided with Bitcoin’s market dominance reaching 60%. The surge, driven primarily by a single flagship product, reinforces the picture of institutional capital consolidating around regulated spot-Bitcoin exposure as the lead crypto asset continues to anchor broader digital-asset positioning.
ETF flows concentrate around flagship Bitcoin products
Spot Bitcoin ETFs took in $457.3 million on December 17, 2025, with the Fidelity Wise Origin Bitcoin Fund (FBTC) contributing $391.5 million of that day’s intake, a top-five inflow day for the fund, according to Farside data. BlackRock’s iShares Bitcoin Trust (IBIT) also saw meaningful demand with $111.2 million in flows, helping push cumulative net inflows beyond $57 billion and total net assets above $112 billion for U.S. spot Bitcoin ETFs, figures that underscore sustained institutional allocation into regulated BTC vehicles.
By contrast, Ethereum-focused ETFs registered notable outflows over the same window. Combined net outflows for Ether products exceeded $449 million across December 15–16, with the largest single-day withdrawals reported in BlackRock’s and Fidelity’s Ethereum products, according to Coinotag data. The split between renewed Bitcoin ETF inflows and concurrent Ethereum ETF outflows highlights a selective institutional rotation inside the crypto ETF complex rather than a uniform risk-on move across all large-cap assets.
Outside BTC and ETH, select altcoin ETFs have attracted targeted capital. XRP-focused ETFs have accumulated nearly $850 million since mid-November, while Solana-based ETFs have drawn roughly $500 million, signaling that investors are still pursuing concentrated non-BTC exposures even as top-down flows and market structure tilt in favor of Bitcoin.
Bitcoin’s dominance reaching 60% reflects a market regime in which capital is consolidating in the largest protocol, a dynamic typically associated with relatively weaker performance from broad altcoin baskets. The December 17 inflow spike into U.S. spot BTC ETFs translated into tangible buy-side support, with Bitcoin briefly approaching $90,000 before settling near $87,000, illustrating how ETF demand can underpin price momentum even amid elevated volatility.
For traders and treasuries, the current configuration translates into two immediate operational priorities: liquidity and basis management across spot and derivatives venues. Heavier ETF demand can widen spot-futures basis and reshape perpetual funding conditions, directly influencing execution costs and hedging efficiency for larger institutional orders. For product and compliance teams, the concentration of flows into a small number of flagship vehicles elevates the importance of monitoring redemption dynamics, custody capacity and reporting obligations under 40 Act–style frameworks as assets under management scale.
The renewed inflows into U.S. bitcoin ETFs and Bitcoin’s 60% dominance mark a phase of concentrated institutional demand that structurally favors BTC over many altcoins for the time being. Market participants will be watching whether ETF flow momentum persists and whether dominance can hold above the 60% threshold in coming sessions as key signals for the durability of this Bitcoin-led regime.
