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 …