The cash-laden institutions responsible for pumping hefty sums into spot bitcoin exchange traded funds (ETFs) this past quarter have been revealed, thanks to recent 13F documents filed with the U.S. Securities and Exchanges Commission (SEC).

One of the world’s largest hedge funds, Millennium Management, plowed nearly $2 billion into bitcoin ETFs, while other notable entities such as investment bank Morgan Stanley and even the the State of Wisconsin Investment Board, invested hundreds of millions into the recently approved investment vehicles.   

The SEC requires all institutional investment firms managing $100 million or more to report their holdings on a quarterly basis via Form 13F by a certain deadline, which fell on May 15 this year for Q1 filings.

Eleven spot bitcoin ETFs —– some managed by prestigious firms such as BlackRock, which led the way with 414 reported 13F holders of its fund, according to Bloomberg ETF Analyst, Eric Balchunas — were approved in January, opening the door to the categorization of bitcoin as a mainstream asset. 

Read more: There Are Now 11 Spot Bitcoin ETFs. Here’s the One That’s Best for You

And now, many consider the large stakes purchased by Millennium Management and others, as further legitimization of the dominant cryptocurrency.

“Normally you don’t get these big fish institutions in the 13Fs for a year or so (when the ETF gets more liquidity),” Balchunas posted on X. “It’s mind-boggling,” he later told Unchained.

The Big Rollers

So far, it appears Millennium Management’s nearly $2 billion stake in five different bitcoin ETFs is the largest among institutional investment managers, representing just over 3% of its current $64 billion in total assets under management (AUM).

Institutional investors will sometimes diversify their holdings across multiple providers.  

The company disclosed an $844 million investment in BlackRock’s ETF (IBIT), $806 million in Fidelity’s (FBTC), $202 million in Grayscale’s (GBTC), and roughly $44 million apiece in the Bitwise (BITW) and Ark (ARKB) ETFs.

Read more: Why Spot Ether ETFs Will Likely Have to Wait Until After the Presidential Election to Be Approved

But quantitative trading firm Susquehanna International Group comes in at a close second with roughly $1.3 billion invested across all ten active ETFs, with more than $1 billion of that in Grayscale’s fund.

The firm describes itself as “an early entrant to the cryptocurrency market” that trades “cryptocurrencies around the clock,” so the company’s bullish position on bitcoin ETFs shouldn’t come as a surprise. 

Balchunas also pointed out that Susquehanna is a market maker, or liquidity provider, which is why it holds some of all active bitcoin spot ETFs.

Read more: Hong Kong Doesn’t Define Ether as a Security, Says Issuer as Spot Crypto ETFs Go Live

“They hold all the ETFs as inventory in order to make markets for other investors,” Balchunas explained.  

Bracebridge Capital, an investment manager based out of Boston, Massachusetts, reported approximately $434 million in spot bitcoin ETF investments. About $307 million of that was in Ark’s fund, $100 million in BlackRock’s, and the rest ($26 million) was in the Grayscale ETF.

Boothbay Fund Management out of New York City purchased a total of $377 million spot bitcoin ETF units from BlackRock ($150 million), Fidelity ($105 million), Grayscale ($70 million) and Bitwise ($52 million).

Investment bank Morgan Stanley, which in April reportedly gave permission to its 15,000 brokers to start pitching bitcoin ETFs, disclosed holdings of nearly $270 million in Grayscale’s spot bitcoin ETF, with a smaller $2 million stake in Ark’s fund.

One of the more notable investors was the State of Wisconsin Investment Board, which, per its filing, bought almost $100 million worth of BlackRock’s bitcoin ETF and invested another $63 million in Grayscale’s fund.

According to its website, the entity has close to $160 billion in assets that it manages on behalf of the Wisconsin Retirement System, the State Investment Fund, and other state trust funds. 

Its official asset allocation strategy includes designating 19% of its capital to “inflation protection,” which could explain why bitcoin—widely considered an inflation hedge—would be an attractive investment to the organization.