US spot bitcoin exchange-traded funds recorded $2.65 billion in net inflows in September, their second-largest monthly total since October 2025, according to SoSoValue data cited by The Block. The figure trails only August's $3.52 billion and sits comfortably above the monthly run-rate the funds have posted through most of the past year, signaling that institutional demand for regulated bitcoin exposure has held firm rather than faded with summer's price volatility.

For issuers, the flow picture carries direct operational weight. Two consecutive months above $2.5 billion in net creations translate into fee revenue, primary-market share activity and balance-sheet bitcoin accumulation through authorized participants — the plumbing that has made the US spot ETF wrapper the dominant vehicle for traditional finance exposure to the asset class.

How do ether ETFs compare?

Spot ether ETFs posted their own solid September, drawing $832.43 million in net inflows — the second-best month for those products since August 2025, though well short of August's $1.85 billion. The first trading day of October split the two categories: bitcoin ETFs added $102.7 million on October 1, while ether ETFs bled $55.4 million in net outflows, a reminder that daily positioning can diverge sharply even when the monthly trend points the same direction.

Why do analysts read the flows as durable?

Dominick John, an analyst at Zeus Research, told The Block that the inflow figures show institutional demand "has not faded" and that large investors are still treating dips as buying opportunities rather than exits. He framed the September data as evidence of a lasting recovery rather than a brief uptick.

"With the Q4 bottom seemingly established, continued ETF inflows also signal improving market sentiment and a potentially more bullish setup heading into the final quarter," John said.

He also pointed to the Crypto Fear & Greed Index, which stood at 69 — "greed" territory but short of extremes. John said that level suggests "sentiment has strengthened without reaching extreme levels," leaving room for buyers to keep adding before positioning becomes stretched. Bitcoin traded at $86,626, up 3.1% in 24 hours, while ether gained 1% to $2,735, according to The Block's price page.

What comes next for flows?

Attention now shifts to a cluster of US macro releases that could reset rate expectations — and, with them, the institutional risk appetite that drives ETF creations and redemptions.

"The Oct. 8 jobless claims report will offer another read on the U.S. labor market, while inflation data and Fed commentary could shift rate expectations," John said.

The jobless claims report lands Thursday, October 8. Traders will pair that release with incoming inflation prints and Federal Reserve commentary to gauge the policy path. Any surprise on those fronts is likely to move bitcoin and ether ETF flows in tandem, given how closely institutional positioning now tracks rate expectations. Whether October sustains September's pace will offer the next clean read on the durability of the institutional bid.