The leading Bitcoin ETF inflow was Fidelity's FBTC, which raised an impressive $131.3 million. Bitwise's BITB also performed well, with inflows of $86.3 million.

Interestingly, Grayscale's GBTC, which has seen capital outflows over the past four months, saw sentiment turn around, registering $27 million in inflows.

This shift may indicate a change in the perspective of investors who are investing in the largest Bitcoin investment resources in the world.

Recent quarterly 13F filings with the US Securities and Exchange Commission (SEC) have shown that institutional investors are actively buying spot Bitcoin ETFs.

Prominent hedge fund Millennium Management, with over $64 billion in assets under management, holds a significant portfolio of $2 billion in various spot Bitcoin ETFs, including BlackRock's IBIT, Fidelity's FBTC, Grayscale's GBTC, ARKB Ark Invest and Bitwise's BITB. Other notable investors include Elliot Capital and Apollo Management Holdings.

The Wisconsin Investment Board has made a groundbreaking move by committing $163 million to a Bitcoin ETF, becoming one of the first U.S. public pension funds to do so.

These allocations were split between BlackRock's IBIT ($99.1 million) and Grayscale's GBTC ($63.6 million). The government pension fund's decision to invest in a Bitcoin ETF marks a significant step towards mainstream adoption of cryptocurrencies.

Positive sentiment in the market can be explained by the publication of April data on the US Consumer Price Index (CPI), which turned out to be lower than expected and amounted to 0.3%. This key indicator of inflation has fueled optimism among investors about the possibility that the Federal Reserve will cut interest rates and inject more liquidity into the market - a scenario that has historically favored high-risk assets such as cryptocurrencies.

As interest in Bitcoin ETFs has renewed, the price of Bitcoin has risen significantly, reaching a high of $66,350 during early Asian trading on May 16.

This marks a remarkable recovery for the cryptocurrency, which is now just 10% away from its all-time high of $73,750 reached on March 14.