Bitcoin spot exchange-traded funds (ETFs) recorded a net outflow of $450.4 million in a day, the biggest since late June.

On Sept. 16 (local time), blockchain outlet Cointelegraph reported that the outflows coincided with a decline in bitcoin prices and the failure of the Clarity bill to make progress in the U.S. Senate.

Farside data showed the ETFs posted a net inflow of $159.9 million on Sept. 15, before flows reversed a day later. The amount was the largest since a $469 million outflow on June 24. At the time, selling in technology stocks pressured risk assets broadly and money left bitcoin spot ETFs.

Outflows were concentrated in some large products. Fidelity's FBTC recorded the biggest outflow at $214.8 million. It was followed by $161.7 million from BlackRock's iShares Bitcoin Trust, $44.1 million from Grayscale's GBTC, $17.4 million from the Ark-21Shares Bitcoin ETF and $12.4 million from the Bitwise Bitcoin ETF.

The market also showed weakness. Bitcoin traded at $75,700, down 2.5 percent over the past 24 hours. The roughly $450 million outflow came as bitcoin was falling. The flow stands out for flipping immediately from the previous day's inflows. Fidelity and BlackRock products led the overall move as the top sources of outflows.

Political factors also weighed on sentiment. The Clarity bill has been cited as a major cryptocurrency bill, but it failed to advance in the Senate. As a result, the U.S. cryptocurrency industry is shifting the focus of its response toward regulators.

The figures show that bitcoin spot ETF flows are reacting sensitively to price swings and policy uncertainty. With a price drop and a stalled bill overlapping to drive large outflows, the market is expected to watch in the near term whether changes in the U.S. regulatory environment, along with bitcoin price moves, can help ETF inflows recover.