U.S. spot Bitcoin exchange-traded funds (ETFs) returned to positive territory on September 17, recording $159 million in total net inflows, while spot Ethereum ETFs extended their outflow streak to a third consecutive day with roughly $39.24 million in net withdrawals.

Net inflows occur when money entering a fund category exceeds money leaving it during a trading session, while net outflows signal the opposite, which is why daily flow tallies are watched as a running record of how capital moves through these products.

The session's Bitcoin ETF result was driven entirely by BlackRock's iShares Bitcoin Trust (IBIT), which was the only spot Bitcoin ETF to report net inflows for the day. The figures suggest capital continued to move into BlackRock's Bitcoin product even as other funds the category failed to attract fresh net investment.

BlackRock's IBIT Drives All of the Day's Bitcoin ETF Inflows

BlackRock's IBIT stood apart from the rest of the U.S. spot Bitcoin ETF market by generating all of the category's net inflows for the session. That concentration means the $159 million total did not reflect broad-based buying across multiple funds; instead, demand was focused on a single product rather than being spread across the wider lineup of U.S.-listed spot Bitcoin ETFs.

The distinction can be important when evaluating ETF activity. Strong headline inflows may appear robust at first glance, but the distribution of those flows can provide additional insight into where investor demand is actually concentrated.

Daily ETF flow figures remain an important indicator for tracking demand from investors seeking Bitcoin exposure through traditional financial markets. Spot ETFs are built to hold the underlying asset and trade through conventional brokerage accounts, which is why their daily creations and redemptions offer a window into how traditional market participants are adjusting their crypto exposure.

The September 17 flow data was highlighted in a post from Wu Blockchain, an account that tracks crypto market and on-chain activity:

Spot Bitcoin ETFs Record $159 Million in Net Inflows on Sept. 17 On Sept. 17 (ET), spot Bitcoin ETFs recorded total net inflows of $159 million, with BlackRock's IBIT being the only fund to report net inflows. Spot Ethereum ETFs saw total net outflows of $39.2445 million,… — Wu Blockchain (@WuBlockchain) September 18, 2026

Source post: Wu Blockchain on X

Ethereum ETFs Extend Outflow Streak to Three Consecutive Days

While Bitcoin ETFs moved back into positive territory, spot Ethereum ETFs continued to face redemptions. Ethereum funds recorded approximately $39.24 million in total net outflows on September 17, and the latest withdrawals extended the category's net outflow streak to three consecutive trading days. A streak of that length means outflows outweighed inflows in each of those individual sessions, a pattern that flow trackers monitor to separate isolated daily swings from sustained redemption pressure.

The contrasting performance highlights a divergence between the two largest U.S. spot crypto ETF categories. Bitcoin products attracted fresh capital during the session, while Ethereum funds continued to lose assets.

Attention now turns to whether Bitcoin ETF inflows can continue in upcoming sessions and whether Ethereum funds can reverse their three-day run of withdrawals, with each new daily flow report offering the next data point on both questions.

Source: CoinoMedia