BlackRock's iShares Bitcoin Trust (IBIT) has emerged as the largest Bitcoin fund, surpassing Grayscale's GBTC, following an impressive $102 million inflow on Tuesday. This development marks a significant shift in the Bitcoin ETF landscape, with IBIT now holding a substantial $19.68 billion worth of Bitcoin. Grayscale's GBTC, on the other hand, has been experiencing outflows, with a net asset value of $19.65 billion as of Wednesday.

The investment giant, BlackRock, has been expanding its presence in the cryptocurrency market. Recently, it added IBIT to its income and bond-focused funds, further solidifying its position. The firm's Strategic Income Opportunities Fund (BSIIX) and Strategic Global Bond Fund (MAWIX) have allocated $3.56 million and $485,000 to IBIT shares, respectively, as confirmed by recent SEC filings.

The fee structure has played a crucial role in this transition. Grayscale's GBTC carries a 1.5% management fee, which has driven investors towards more economical options like IBIT. The low fees of IBIT have attracted investors, leading to a significant increase in inflows.

US spot Bitcoin ETFs have been experiencing a streak of net positive investments, with a total daily net inflow of $45.14 million on Tuesday, marking the 11th consecutive day of inflows. This is the longest streak of positive flows since February. The cumulative total net inflows since January have reached $13.73 billion, with the 11 spot Bitcoin ETFs seeing total net inflows of over $2 billion in the past 11 days.

Fidelity's FBTC reported the second-largest net inflows of $34.35 million, while other funds from Ark Invest and 21Shares, Bitwise, Invesco and Galaxy Digital, Valkyrie, and WisdomTree saw single-digit gains on Wednesday. The price of Bitcoin has also seen a 0.73% increase in the past 24 hours, reaching $68.126.

This sudden shift in IBIT's fortunes can be attributed to the recent bullish sentiment for Bitcoin and the broader crypto market. The listing approval for ether (ETH) ETFs and renewed support for crypto among US political parties have contributed to the increased buying activity for IBIT. After experiencing low or even zero inflows before May 15 and seeing its first-ever day of outflows in April, IBIT has now emerged as a leader in the Bitcoin ETF space.

In conclusion, BlackRock's IBIT has taken the top spot among spot Bitcoin funds, surpassing Grayscale's GBTC. The investment giant's expansion into the cryptocurrency market, combined with the low fees of IBIT, has driven investors towards this more economical option. As the crypto market continues to evolve, it will be interesting to see how this shift in leadership impacts the future of Bitcoin ETFs.