U.S. spot Bitcoin ETFs recorded $731 million in net inflows on Sept. 3, their strongest single trading day since January.BlackRock’s IBIT led the session with $454 million, followed by $138 million for ARKB and roughly $74 million for Fidelity’s FBTC.Combined Bitcoin ETF net assets reached $103.34 billion, equal to just over 6% of Bitcoin’s market capitalization.The inflows followed a $236 million withdrawal on Sept. 1, when IBIT alone recorded roughly $201 million in redemptions.