US spot Bitcoin ETFs attracted $998.9 million in net inflows on September 21, 2026, according to SoSoValue data published September 22 at 2:22 PM UTC. The figure marks the strongest single-day performance for spot BTC funds in 2026, surpassing the previous year-to-date record of $844 million set on January 14, and the best daily result since October 6, 2025.
The surge was driven by three funds. BlackRock iShares Bitcoin Trust (IBIT) drew $381.4 million, ARK 21Shares Bitcoin ETF (ARKB) added $289.1 million, and Fidelity Wise Origin Bitcoin Fund (FBTC) attracted $238.8 million. Together these three accounted for roughly $909 million, or 91% of the day's total. No fund recorded a net outflow. Daily trading value reached $4.57 billion, and total net assets under management climbed to over $110 billion, an increase of more than $8 billion in a single session.
The broader crypto market followed. On Tuesday, September 22, total cryptocurrency market capitalization surpassed $3 trillion for the first time since January, as reported by 24/7 Wall St. The milestone was fueled by a convergence of factors: the US Treasury's expanded bond buyback program announced in late August, which released roughly $740 billion of cash into markets; the forced closure of approximately $920 million in short positions in a single day, per CoinGlass data; and the SEC's temporary conditional approval for venues to trade tokenized US stocks on public blockchains, with roughly $465 million in tokenized equities already trading on Solana.
The combined force of ETF inflows and short liquidations pushed Bitcoin above $87,200 on Monday, a gain of roughly 4.7% in 24 hours. The price settled around $85,430 at the close of the session. On Tuesday, market capitalization briefly touched the $3 trillion mark before retreating to approximately $2.95 trillion by Wednesday morning at 06:30 UTC, with Bitcoin trading near $86,400.
Ether ETFs completed the record session: spot ETH funds attracted approximately $270 million, the best single-day performance of 2026, with BlackRock Ethereum ETF (ETHA) leading at $110 million. The three-day net inflow total across Bitcoin ETFs from September 17 to 21 reached approximately $1.6 billion, a sharp reversal from the $450 million in outflows on September 15 and $296 million on September 16.
Caution remains warranted. Open interest on perpetual futures reached $160 billion, the highest level since late October 2025. This leverage amplifies moves in both directions: the same buying pressure that pushed the market past $3 trillion can quickly turn into selling if prices reverse. Additionally, despite the weekly rally, four of the top five cryptocurrencies by market capitalization remain negative year-to-date: Ethereum (-6.5%), XRP (-16.5%), Solana (-4.2%), and Bitcoin itself (-1.2%).
The cumulative net flow for spot BTC ETFs in 2026 remains negative, at roughly $464 million in net outflows year-to-date, despite the recent record days. The prior peak of $844 million on January 14 was followed by weeks of mixed flows before a mid-September selloff erased gains.
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