United States spot Bitcoin exchange-traded funds (ETFs) have seen their biggest inflow day in over four months, with over half a billion dollars in inflows. 

The 11 ETFs saw aggregate net inflows of $555.9 million on Oct. 14, their largest daily net inflow since early June, according to data from Farside Investors.

The big inflow day comes as Bitcoin (BTC) tapped a two-week high of $66,500 during late trading on Oct. 14. 

ETF Store President Nate Geraci called it a “monster day” for spot BTC ETFs, adding that they were now approaching $20 billion in net inflows over the past ten months. 

“Simply ridiculous and blows away every pre-launch demand estimate,” he said in an Oct. 15 X post. “This is NOT ‘degen retail,’ it’s advisers and institutional investors continuing to slowly adopt.”

The Fidelity Wise Bitcoin Origin Fund (FBTC) was the leader of the pack with an inflow of $239.3 million — its highest since June 4. 

The Bitwise Bitcoin ETF (BITB) had a little over $100 million, while BlackRock’s iShares Bitcoin Trust (IBIT) saw inflows of $79.6 million.

Ark 21Shares Bitcoin ETF (ARKB) had inflows of just under $70 million and the Grayscale Bitcoin Trust (GBTC) saw its first inflow for October at $37.8 million — also its highest since early May. 

In an Oct. 14 X post, Bloomberg senior ETF analyst Eric Balchunas compared Bitcoin ETFs to gold-based products stating that since the January launch of the BTC funds, the asset has hit an all-time high five times.

Meanwhile, gold has hit record highs 30 times this year, but gold ETFs have only seen $1.4 billion in net inflows compared to more than $19 billion for Bitcoin ETFs, Balchunas explained. 

Related: Bitcoin ETFs end three-day skid with $254M inflow

Ethereum funds were not enjoying the same momentum, however, with zero net flows for Bitwise, VanEck, Franklin, and Grayscale and minor flows for Fidelity and Invesco. 

The BlackRock iShares Ethereum Trust (ETHA) had an inflow of $14.3 million, bringing the total to $17 million. 

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