Susquehanna International Group, LLP (SIG), a big investment company, recently told the Securities and Exchange Commission (SEC) that it owns more than $1.8 billion in Bitcoin exchange-traded funds (ETFs). They did this by filing a document called 13F-HR.

In this document, they said their biggest investment is in a Bitcoin ETF called GBTC, which is run by a company called Grayscale. They have over $1 billion invested in it.

SIG also owns parts of other Bitcoin ETFs. Some of these are ARK 21SHARES BITCOIN ETF, BITWISE BITCOIN ETF TR, and ISHARES BITCOIN TR. All these together add up to more than $1.8 billion.

One interesting thing SIG invested in is a Bitcoin ETF that lets them make money when the price of Bitcoin goes down. It's called ProShares Short Bitcoin ETF. They also invested in another ETF that makes them extra money when Bitcoin's price goes up, called Volatility Shares 2x Bitcoin ETF.

These ETFs allow big companies to invest in Bitcoin without actually having to buy Bitcoin themselves. This makes it easier and more regulated for them.

SIG's investment in Bitcoin ETFs shows that big companies are starting to take Bitcoin seriously. They believe it's a good idea to have some Bitcoin as part of their investments.

Experts think more big companies will start talking about their Bitcoin investments soon. They'll have to file documents with the SEC just like SIG did. This will give us a better idea of who else is investing in Bitcoin.