U.S. spot Bitcoin and Ethereum exchange-traded funds posted a combined $577 million in net inflows on Sept. 18, with Bitcoin products accounting for roughly three-quarters of the day's allocations.

Spot Bitcoin ETFs Lead With $433 Million in Net Inflows

Spot Bitcoin ETF products recorded $433 million in net inflows on Sept. 18 (ET), the larger of the two reported totals for the session. The figure reflects net flows across the U.S. spot Bitcoin ETF complex for that single trading day. Daily net flow readings like this one are built from fund share creations and redemptions, so they serve as a gauge of demand moving through these regulated vehicles rather than a read on price direction.

The Sept. 18 result extends a pattern of positive Bitcoin ETF flow days that has drawn sustained attention from market observers. On a prior session, Bitcoin ETFs added $100 million while Solana, XRP, and Ethereum ETF products were in the red, underscoring how unevenly inflows can be distributed across the asset class on any given day.

Spot Ethereum ETFs Add $144 Million as Combined Total Reaches $577 Million

Spot Ethereum ETFs recorded $144 million in net inflows on Sept. 18 (ET), lifting the combined one-day total across both product categories to $577 million. Bitcoin ETFs accounted for roughly 75% of the combined figure, with Ethereum funds making up the remaining 25%.

The Ethereum result is notable in context: on a single day earlier in September, Ethereum ETFs drew $226 million, nearly matching Bitcoin's haul for that session. The Sept. 18 figures show a wider gap between the two assets, with Bitcoin pulling in three times the Ethereum total. On a weekly basis, Ethereum ETFs have pulled in $713 million against Bitcoin's $884 million, suggesting the gap can narrow considerably when aggregated over multiple sessions.

What the Sept. 18 ETF Flow Figures Show

• Spot Bitcoin ETFs recorded $433 million in net inflows on Sept. 18 (ET).
• Spot Ethereum ETFs recorded $144 million in net inflows during the same session.
• Combined net inflows across both product types totaled $577 million for Sept. 18 (ET) only.

Both spot Bitcoin and spot Ethereum ETF products posted positive net inflows on Sept. 18 (ET), meaning more capital entered the funds than exited over the session, and both the Bitcoin and Ethereum U.S. spot ETF complexes drew net new allocations on the same day. The figures reflect a single trading day and do not, on their own, indicate a multi-day trend. Because flow data for both products is tracked daily by The Block's ETF flow dashboards, subsequent sessions will add the data points needed to show whether Sept. 18's combined total was extended or offset in the days that followed.

Disclaimer: This article is for informational purposes only and does not constitute financial or investment advice. Cryptocurrency and digital asset markets carry significant risk. Always do your own research before making decisions.