U.S. Spot Bitcoin ETFs Take In About $1.7 Billion Over Two Days as Bitcoin Tops ETF Cost Basis

About $1.7 billion flowed into U.S. spot Bitcoin exchange-traded funds over two trading days as Bitcoin traded above Bloomberg Intelligence’s estimated aggregate ETF cost basis of about $81,722 per coin, putting the average ETF holder back in profit for the first time since January.

U.S. spot Bitcoin ETFs took in $998.95 million in net inflows on Monday, Sept. 21, according to SoSoValue data cited by The Block, CoinDesk and Decrypt. They added about $714.75 million more on Tuesday, Sept. 22, according to SoSoValue data reported by CoinNess and other market outlets. Combined, that amounts to roughly $1.7137 billion over the two sessions.

The Monday total was notable for its size and timing. Reporting described the Sept. 21 haul as the largest single-day inflow since Oct. 6, 2025, and among the biggest daily totals since U.S. spot Bitcoin ETFs began trading in January 2024. The products were approved earlier that month and launched on Jan. 11, giving investors a regulated fund structure for gaining exposure to Bitcoin without buying the token directly.

Bitcoin traded in the mid-$80,000 range during the two-day stretch, with reports citing highs near $86,000 to $87,000. One historical series put the Sept. 21 close at about $86,602.91. That left the cryptocurrency above Bloomberg Intelligence’s estimated aggregate ETF cost basis of about $81,722 per bitcoin.

James Seyffart, an analyst at Bloomberg Intelligence, said that move put the average ETF investor back in positive territory. “NEW: The average Bitcoin ETF Holder is back above water for the first time since January. The rally this morning has bitcoin:native above our estimated ETF cost basis of $81,722 per coin,” he said in comments reproduced by Decrypt and other outlets. The estimated cost basis is a market analytics measure, not an official regulatory figure, but it is widely used as a shorthand for whether the average ETF buyer is sitting on gains or losses.

For the big Sept. 21 inflow day, the largest contributions came from BlackRock’s iShares Bitcoin Trust, or IBIT, at $381.4 million, ARK 21Shares Bitcoin ETF, or ARKB, at $289.1 million, and Fidelity Wise Origin Bitcoin Fund, or FBTC, at $238.8 million, based on SoSoValue figures cited by The Block and CoinDesk. U.S. spot Bitcoin ETFs have been trading since January 2024.