Bitcoin ETFs see $433M in inflows as Ethereum ETFs add $144M in single-day surge

US spot Bitcoin ETFs pulled in $433 million in net inflows on September 18, while spot Ethereum ETFs added $144 million on the same day. Both figures represent a meaningful rebound from mixed and negative flow sessions that preceded them.

Fidelity’s FBTC was the standout performer on the Bitcoin side, attracting $311 million of the day’s total. BlackRock’s IBIT contributed $108 million. On the Ethereum front, the roles reversed: BlackRock’s ETHA led with $114 million, while Fidelity’s FETH added roughly $26 million.

The numbers behind the flows

The $433 million Bitcoin ETF inflow day arrived against a backdrop of total Bitcoin ETF assets under management reaching $102.532 billion, a figure that now represents 6.29% of Bitcoin’s entire market capitalization. Cumulative historical net inflows into these products have hit $55.161 billion since their launch.

Ethereum ETFs, while smaller in absolute terms, are growing at a pace that demands attention. Total AUM for spot Ethereum ETFs now stands at $16.719 billion, representing 5.2% of Ethereum’s market cap. Cumulative inflows have reached $13.250 billion.

The gap between 6.29% market cap penetration for Bitcoin ETFs and 5.2% for Ethereum ETFs is narrower than many expected at this stage.