In an extraordinary display of investor interest, US spot Bitcoin exchange-traded funds (ETFs) witnessed a fourth consecutive day of inflows, totaling $257.34 million on Thursday. This remarkable surge in investment marks a significant milestone in the adoption of Bitcoin ETFs.

BlackRock's IBIT, the second-largest ETF by net asset value, led the charge with an impressive $94 million inflow. Fidelity's FBTC fund and Ark Invest and 21Shares' Bitcoin ETF followed closely, with $67 million and $62 million inflows, respectively.

Grayscale's GBTC, which had previously experienced significant outflows, saw a notable turnaround with a daily net inflow of $4.64 million. Other funds, including Valkyrie's Bitcoin ETF and those from Bitwise, Franklin Templeton, Invesco, and Galaxy Digital, also experienced substantial inflows.

This unprecedented growth in investor interest coincides with the first-quarter 13F reporting season on Wall Street. Major financial players have disclosed their stakes in spot Bitcoin funds, revealing a greater-than-expected interest in the asset class. IBIT, in particular, has seen a remarkable 414 reported holders in its first 13F season, a testament to its growing popularity.

As of the end of March, institutional investors such as Morgan Stanley, Millennium Management, and the State of Wisconsin Investment Board have disclosed significant holdings in spot Bitcoin ETFs, totaling over $2.3 billion.

The cumulative net inflows for the 11 US spot Bitcoin ETFs have reached an impressive $12.40 billion, according to SoSoValue data. While trading volume remains below its peak level in March, the sustained interest in Bitcoin ETFs signals a growing acceptance of the asset class among institutional investors.