The Bitcoin bulls are back — at least if ETF flows are any guide.

U.S. spot bitcoin exchange-traded funds took in $999 million in new investment Monday, according to Farside Investors data. It was the funds' biggest single day since October 6, when they received more than $1.2 billion and the price of the leading cryptocurrency hit a new all-time high of $126,080. Daily flow tallies like Farside's have become one of the most closely watched gauges of institutional appetite for bitcoin since the funds launched.

Bitcoin's price recently stood at $86,552 after scraping $87,330 on Monday. Over the past seven days, the coin has surged by nearly 13%.

U.S. bitcoin ETFs, approved by the Securities and Exchange Commission (SEC) in 2024, gave investors a way to gain exposure that they previously lacked, offering a stake in bitcoin's price without requiring them to hold the asset directly. Wall Street firms can now quickly buy shares of funds managed by the likes of BlackRock, Fidelity, and Morgan Stanley, among others. When large investment hits the funds, the price often moves significantly — as it did on Monday.

Bloomberg ETF analyst James Seyffart said on Monday that the average ETF buyer is now in profit, after the estimated ETF cost basis surged above $81,72 for the first time since January. The cost basis is a running estimate of the average price at which ETF investors as a whole have bought, making it a rough barometer of whether the typical fund holder is sitting on gains or losses.

BlackRock's iShares Bitcoin Trust received the largest share of Monday's investment at $381.4 million. The ARK 21Shares Bitcoin ETF took in $289.1 million, while Fidelity's Wise Origin Bitcoin Fund received $238.8 million — three of the largest products in the category.

Renewed investor interest in Bitcoin has come after the artificial intelligence stock rally cooled and the U.S. Department of the Treasury said in August that it would at least double the size of its liquidity-support buyback operations, in which the government repurchases outstanding debt to shore up market liquidity. Analysts said the move pushed 30-year Treasury yields down, weakened the dollar, and made assets like bitcoin more attractive. Following the announcement, the bitcoin price had its best run in years.

A Tuesday report from crypto market data firm CryptoQuant said that the leading cryptocurrency crossed above its 365-day moving average — a signal that the asset has finished being in a bear market. The 365-day moving average tracks bitcoin's average price over a full year and is widely used to separate long-term bull and bear phases. Whether Monday's near-$1 billion haul marks a sustained return of institutional demand — and whether bitcoin can keep its place above the long-term average CryptoQuant flagged — are the developments likely to shape the next phase of the market.

This article first appeared on Bitcoin Magazine and was written by Mathew Di Salvo.