A collection of large-scale Bitcoin owners—known as whales—have moved 94,504 bitcoins, worth over $1 billion, to an unknown wallet. That’s over 0.5 percent of all coins in circulation, making the recipient the owner of the fifth richest Bitcoin wallet in existence.

The bitcoins were sent to a single wallet at 3am UTC this morning from 15 addresses. Over half of the bitcoins, 53,000 of them, came from a single address.

The transaction saw the price of Bitcoin spike from $10,569 to $10,790 in a matter of hours.

Nobody has claimed ownership over the wallet, and speculations vary.

We don’t have much to go on, apart from the fact that the transaction fee was high—some $700—which suggests that they wanted to confirm the transaction quickly, perhaps for security reasons. Or that the transaction had a lot of inputs that each have their own minimum fee; this is where multiple chunks of Bitcoin are brought together in one transaction.