Institutional investors have returned to the crypto market. After months of heavy selling and pessimism, US Spot Bitcoin ETFs have finally staged a strong comeback.
On Monday, September 21, US Spot Bitcoin ETFs recorded a net inflow of $998.95 million—approximately $1 billion. This marks the largest single-day inflow since October 6, 2025, when Bitcoin hit an all-time high of $126,200. It is the ninth-largest daily inflow since the ETFs launched in January 2024.
This figure is historic because, just a week prior, the ETFs saw an inflow of only $6.2 million—the lowest weekly figure in 141 weeks of trading. Conditions were even worse in mid-July, with a 30-day average daily outflow of $88.9 million and trading volumes down 80% from the October 2025 peak.
Who bought? BlackRock took the lead.
Monday's entire inflow was driven by institutional giants. There were no outflows from any fund; even Grayscale’s GBTC—previously the primary source of selling pressure during the ETF era—saw a slight inflow, signaling that selling by legacy, high-fee holders has likely concluded.
Breakdown:
BlackRock IBIT: $381.37 million – IBIT alone now holds $68.29 billion in assets, representing 3.91% of Bitcoin's total market capitalization. Its total inflow since launch has reached $64.5 billion. ARK 21Shares ARKB: $289.12 million | Fidelity FBTC: $238.84 million | Morgan Stanley MSBT: $61.67 million
Bitwise BITB: $21.56 million
Three major funds—IBIT, ARKB, and FBTC—accounted for over 90% of the day's inflows.
Trading volume in the Bitcoin ETF market also reached between $4.5 billion and $4.57 billion that day. High turnover indicates that these inflows represented genuine liquidity rather than a fluke in a thin market.
And this wasn't limited to Bitcoin. US Spot Ether ETFs also saw inflows of $270 million that same day, with BlackRock’s ETHA capturing $110 million. Combined, the single-day inflow for BTC and ETH totaled $1.27 billion.
Why is this rebound so significant?
1. Average investor back in profit:
Bitcoin traded above the $86,000–$86,300 range on Monday. According to Bloomberg Intelligence analyst James Seyffart, the cost basis for the average US Spot Bitcoin ETF holder is $81,722. With BTC rising 5% above this level, the average ETF investor is back in profit for the first time since January.
2. September turnaround, though the year remains negative:
Total inflows for September have now reached $1.31 billion, down from August's $3.52 billion. The year-to-date (YTD) figure remains in negative territory, ranging from approximately -$450 million to -$464 million. Since launch, total cumulative net inflows stand at $56.16 billion, with total Assets Under Management (AUM) at $110.14 billion—representing 6.3% of Bitcoin's market cap.
3. Short squeeze + institutional return:
Analysts believe this rally is driven by two factors: ETF demand and a short squeeze. Short positions worth approximately $448.96 million were liquidated. Bitcoin first gained momentum as macro conditions improved, breaking resistance and forcing out bearish positions; ETF inflows followed. In other words, the rally began first, and institutions joined later.
From a technical standpoint, this is also a significant signal. For the first time in 45 weeks, Bitcoin closed above its 50-week moving average—a level considered indicative of a long-term bullish trend.
What to watch next?
The market is now focused on September 22. According to analysts, if inflows exceed $300 million for a fourth consecutive day, the $90,000 target will be confirmed. Conversely, if outflows resume, it would suggest that Monday’s activity was merely a peak rather than the start of a sustained rally.
Overall, following a $4.6 billion rebound, this $999 million day demonstrates that when a giant like BlackRock buys, every single dollar has a direct impact on the spot market. Institutional capital is returning.
