Late on Thursday night, US Eastern time, someone made one of the biggest transactions in bitcoin history: 94,504 bitcoins. At the then-current bitcoin price of around $10,600, this transaction was worth almost exactly $1 billion. It's now worth around $967 million.

Bitcoin's shared transaction ledger is open, but addresses are anonymous by default. As a result, we know that the transaction occurred, but we don't know who made it or why. One analysis indicated that at least a third of the money comes from Huobi Global, a cryptocurrency exchange based in Singapore. So the transaction could reflect big withdrawals from a Huobi customer—or it could mean that Huobi itself was consolidating some of its deposits.

This isn't the largest transaction in bitcoin terms. In 2013, for example, someone moved 194,993 bitcoins in a single transaction. But bitcoins were much less valuable back then, so the transaction was only valued at around $150 million.

An even larger 2011 transaction moved 550,000 bitcoins. But with bitcoins only worth around $3 at the time, this represented around $1.5 million at the time.

However, I can't find any previous examples of bitcoin transactions where the dollar value exceeded $1 billion.

Whoever initiated the $1 billion transfer paid a transaction fee of 0.065 bitcoins—around $690 at the time of the transaction.