The U.S. spot Bitcoin exchange-traded funds (ETFs) marked a historic milestone on March 12th, attracting over $1 billion in net inflows for the first time in a single day. This unprecedented surge in capital inflows coincides with a remarkable bull run in the cryptocurrency market.

Over the past 13 days, investments into spot Bitcoin ETFs have soared, with daily inflows breaching a staggering $11.1 billion. On March 12th alone, Bitcoin ETFs witnessed their biggest-ever daily inflow of $1.045 billion, primarily driven by BlackRock's iShares Bitcoin ETF (IBIT), which accounted for $849 million of the total.

Other prominent ETFs, such as ARK 21Shares Bitcoin ETF (ARK), VanEck Bitcoin Trust ETF (HOLD), and Fidelity Wise Origin Bitcoin Fund (FBTC), recorded comparatively lower contributions of $93 million, $82.9 million, and $51.6 million, respectively.

As a direct consequence of these massive inflows into Bitcoin ETFs and the supporting bull run, the daily inflows of capital being stored on the Bitcoin network have hit an unprecedented $2 billion per day, marking yet another milestone for the ecosystem. Concurrently, the market price of Bitcoin reached a new high of $73,000 at the time of writing.

Among the approved Bitcoin ETFs in the U.S., Franklin Bitcoin ETF (EZBC) has recorded the lowest inflows to date at $148 million, while IBIT holds the lion's share at $11.4 billion. On the other hand, the Grayscale Bitcoin Trust (GBTC) has been consistently shedding capital, with net outflows totaling $11.1 billion over the last 13 days.

Notably, Grayscale's GBTC fell below 50% market share for the first time since spot Bitcoin ETFs began trading in the U.S. on January 11th. On the first trading day of the 10 U.S. spot Bitcoin ETFs, Grayscale's fund accounted for around 99.5% of their total assets under management. However, consistent daily outflows from the GBTC, which averaged $329 million per day last week, have eroded the ETF's market share over time.