Bitcoin ETFs add $2.65 billion in September

US spot bitcoin exchange-traded funds recorded $2.65 billion in net inflows during September, their second-largest monthly total since October 2025. The figure was below August's $3.52 billion but remained far stronger than most months over the preceding year.

Spot ether ETFs added another $832.43 million during September, down from $1.85 billion in August. The two sets of funds therefore finished the month with positive institutional flows even as daily prices remained volatile around interest-rate and regulatory news.

Monthly ETF data smooths over the large reversals visible from one trading day to the next. The September total shows that the listed products accumulated assets across the month despite several short periods of withdrawals.