US spot bitcoin ETFs had their strongest week in almost a year, attracting about $2.4 billion in net inflows between September 21 and September 25. It was the biggest weekly inflow since October 2025, when bitcoin ETFs brought in about $2.7 billion.

The latest inflows also helped turn Bitcoin ETFs' 2026 performance positive. According to data cited in reports from Farside Investors, the funds had been down by roughly $5.8 billion in net flows in mid-July. After last week's strong buying, they were up by about $934 million for the year.

The figures show that investors have returned to bitcoin ETFs after a difficult period earlier in 2026. The biggest inflow came on Monday last week, when investors put almost $999 million into Bitcoin ETFs.

The pace then slowed each day. The funds received about $714.7 million on Tuesday, $347 million on Wednesday, $190.6 million on Thursday and $134.5 million on Friday.

Even though the daily amounts declined, every trading day of the week still recorded a net inflow. The slowdown came as bitcoin's price also weakened. Bitcoin traded above $87,000 early in the week before falling toward the $83,000-$84,000 range.

BlackRock's IBIT attracted the most money during the week, bringing in roughly $1.2 billion.

Fidelity's FBTC was second with about $702 million, while ARK Invest and 21Shares' ARKB received around $295 million.

Morgan Stanley's MSBT also had a strong week, attracting about $203 million. The fund launched in April and recorded its largest weekly inflow during the period covered by the reports.

Since their launch in January 2024, US spot bitcoin ETFs have attracted about $57.6 billion in cumulative net inflows. Their combined assets stood at around $107 billion as of September 29, according to data from SosoValue.

One reason for the continued demand is that bitcoin ETFs give investors an easier way to gain exposure to the scarce digital asset. Instead of buying and storing bitcoin directly, investors can buy ETF shares through traditional investment accounts.

The latest buying also happened despite several challenges in the wider economy, including inflation concerns, Treasury yields and uncertainty over Federal Reserve policy.

Some analysts have linked the strong ETF flows to increased demand from larger investors and broader movements in financial markets.

Bloomberg ETF analyst Eric Balchunas described the recent inflows as a “$4.6b tsunami of cash” in a post on X.

The strong ETF numbers are encouraging for bitcoin demand, but they do not guarantee that bitcoin's price will continue rising.

The decline in daily inflows is one reason investors are watching the next few trading sessions closely. Last Monday's nearly $1 billion inflow was followed by much smaller amounts throughout the week.

The declining trend continued after the weekend, with inflows totaling just $31 million on Monday, September 28. Bitcoin also struggled to stay above $87,000 after reaching that level.

ETF flows are only one factor affecting bitcoin's price. Interest rates, inflation, investor sentiment, leverage and selling pressure can also have a major impact.