U.S. spot bitcoin ETFs recorded $2.65 billion in net inflows in September, their second-largest monthly total since October 2025, according to SoSoValue data. The figure marks a slowdown from August's $3.52 billion but remains well above the levels posted throughout much of the past year, extending what analysts describe as a sustained institutional bid rather than a one-off repricing.

Spot ether ETFs posted a more pronounced deceleration, attracting $832.43 million in September against $1.85 billion in August. Even so, the month ranked as the second-largest inflow month for the ether products since August 2025, indicating that demand for the ETH-based funds, while cooling, has not reversed.

The flows carried into the start of the fourth quarter, though with a split picture. Bitcoin ETFs added $102.7 million on October 1. Ether ETFs moved the other way, shedding $55.4 million on the day — an early signal that the two product categories may be diverging as the quarter opens.

Dominick John, analyst at Zeus Research, told The Block that the September figures suggest institutional demand "has not faded" and point to a more sustained recovery in crypto allocations.

"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.

The flows data landed alongside a firmer tape. Bitcoin climbed 3.1% over the 24 hours to 1:00 a.m. ET Friday to trade at $86,626, while ether rose 1% to $2,735, according to The Block's price page. The Crypto Fear & Greed Index stood at 69, in greed territory, which John read as a sign that "sentiment has strengthened without reaching extreme levels." Notably, bitcoin's 30-day performance widget on The Block showed a modest 2.23% gain, underscoring that the September inflow story is about accumulation rather than a sharp price move.

For the issuers — the group that includes BlackRock, Fidelity and the other U.S. spot bitcoin ETF sponsors — two consecutive months above $2.5 billion in net creations supports fee revenue and strengthens the case for continued prime brokerage, lending and market-making capacity behind the products. The divergence between bitcoin and ether flows in the first October session will test whether ether ETF demand is stabilizing at a lower run-rate or beginning to roll over.

John said traders will keep watching daily ETF prints as the cleanest real-time proxy for institutional appetite, alongside macro data. "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," he said.

The next test of the trend arrives quickly: daily flow data over the coming sessions, followed by the October 8 jobless claims release, will show whether September's $2.65 billion inflow was the start of a fourth-quarter acceleration or the tail end of the August surge.