Exchange traded funds, or ETFs, in the top cryptocurrency were trading for the first time on Thursday.
And it proved to be a busy day.
Around $4.6 billion in shares in such funds changed hands.
That's according to data from LSEG.
It all came after the ETFs were approved by U.S. regulators.
The Securities and Exchange Commission had given the green light a day earlier.
That followed a decade-long legal tussle with backers of the crypto funds.
SEC boss Gary Gensler still isn't a fan, calling bitcoin a "speculative, volatile asset".
He said approval for the ETFs was in no way an endorsement of virtual money.
Nonetheless, it's a watershed moment for the crypto sector.
Supporters say the funds will make it much easier for people to invest in bitcoin.
They won't have to hold the coins themselves, but can just buy and sell shares in the funds.
And Etoro strategist Ben Laidler says more positives lie ahead for the sector:
"We've got bank regulatory changes; they're going to make it easier for banks to own crypto. I fully expect in the fullness of time, central banks to start owning crypto as part of their FX reserves. You know, all this, I think, is just the sort of gradual natural development of what is a very young, a very small asset class."
Bitcoin itself rose around 0.7% on Thursday, buoyed by the enthusiasm.
Products from BlackRock, Fidelity and Grayscale dominated the first day of trade.
But other big players remain wary.
Vanguard - the top provider of mutual funds - said it had no plans to make bitcoin ETFs available to brokerage clients on its platform.
