More than 600 firms have unveiled substantial investments in spot Bitcoin exchange-traded funds (ETFs) in their 13F filings submitted to the United States Securities and Exchange Commission (SEC) over the past week. According to the disclosed data, professional investment firms have declared ownership of Bitcoin ETFs amounting to a staggering $3.5 billion.

Millennium Management emerges as the largest investor in BTC ETFs, having allocated a whopping $1.9 billion. Their investments include $844.2 million in BlackRock’s iShares Bitcoin Trust (IBIT), $806.7 million in Fidelity’s Wise Origin Bitcoin Fund (FBTC), $202 million in the Grayscale Bitcoin Trust (GBTC), $45.0 million in the ARK 21Shares Bitcoin ETF (ARKB), and $44.7 million in the Bitwise Bitcoin ETF (BITB).

Following closely is Schonfeld Strategic Advisors, a hedge fund managing $13 billion in assets, with a substantial investment of $248 million in BlackRock’s ETF and an additional $231.8 million in Fidelity’s fund, totaling $479 million.

Morgan Stanley, one of the leading financial institutions, has disclosed a substantial investment of $269.9 million in GBTC, solidifying its position as one of the largest GBTC holders. Aristeia Capital, an alternative asset manager, has revealed a $163.4 million investment in IBIT.

Other financial giants such as JPMorgan, Wells Fargo, UBS, BNP Paribas, and Royal Bank of Canada are also on the list of investors. While the recent weeks have witnessed a significant slowdown in inflows, spot Bitcoin ETFs experienced tremendous demand in the first three months following their launch in mid-January.