In the same way a dollar is made up of 100 cents, one bitcoin is composed of 100 million satoshis—or sats, for short. But not all sats are made equal. Those produced in the year bitcoin was created are considered vintage, like a fine wine. Other coveted sats were part of transactions made by bitcoin’s inventor. Some correspond with a particular transaction milestone. These and various other properties make some sats more scarce than others—and therefore more valuable. The very rarest can sell for tens of millions of times their face value; in April, a single sat, normally worth $0.0006, sold for $2.1 million.

Restey is part of a small, tight-knit band of hunters trying to root out these rare sats, which are scattered across the bitcoin network. They do this by depositing batches of bitcoin with a crypto exchange, then withdrawing the same amount—a little like depositing cash with a bank teller and immediately taking it out again from the ATM outside. The coins they receive in return are not the same they deposited, giving them a fresh stash through which to sift. They rinse and repeat. In April 2023, when Restey started out, he was one of the only people hunting for rare sats—and the process was entirely manual. But now, he uses third-party software to automatically filter through and separate out any precious sats, which he can usually sell for around $80. “I’ve sifted through around 230,000 bitcoin at this point,” he says.

Restey has unearthed thousands of uncommon sats to date, selling only enough to cover the transaction fees and turn a small profit—and collecting the rest himself. But the window of opportunity is closing. The number of rare sats yet to be discovered is steadily shrinking and, as large organizations cotton on, individual hunters risk getting squeezed out. “For a lot of people, it doesn’t make [economic] sense anymore,” says Restey. “But I’m still sat hunting.”