BlackRock's iShares Bitcoin Trust (IBIT) ETF saw a massive inflow of $290 million on May 21, accounting for 95% of the total inflow into US spot Bitcoin ETFs that day. This is the highest inflow for BlackRock's ETF since April 5, reversing a six-week trend of low or zero inflows. The latest figures bring the total inflows for the BlackRock fund to $16 billion since its launch. Meanwhile, Grayscale's GBTC spot ETF, an industry leader, registered zero flow on May 21, maintaining a five-day streak without an outflow.