BlackRock’s (NYSE: BLK) IBIT (NASDAQ: IBIT) spot Bitcoin exchange-traded fund crossed 250,000 BTC ($17.7 billion) in assets under management on Wednesday, just 11 weeks after trading began on Jan. 11. BlackRock’s Bitcoin ETF had already accumulated 245,951 BTC as of Tuesday, according to its latest fund disclosures. IBIT’s $323.8 million (4,702 BTC) worth of net inflows yesterday, per BitMEX Research data, were enough to tip it over the milestone. Speaking to Fox Business’ Charlie Gasparino and Liz Claman on Wednesday, BlackRock CEO Larry Fink said, “IBIT is the fastest-growing ETF in the hist…