James Howells said he threw away the hard drive while cleaning during the summer and last Friday he realized the part was where he had stored the 7,500 Bitcoins he created in 2009, when the currency value of Bitcoins was considerably lower, The Guardian reported Friday.
"You know when you put something in the bin, and in your head, say to yourself, 'That's a bad idea?' I really did have that," Howells said. "I don't have an exact date. The only time period I can give -- and I've been racking my own brains -- is between 20 June and 10 August. Probably mid-July."
The Bitcoins were worth about $818,000 when he threw the hard drive away during the summer, but the price has since soared, with the worth of a single Bitcoin surpassing $1,000 Wednesday.
The actual contents of the hard drive was the cryptographic "private key" needed to access and spend the Bitcoins, Howells said. He said the currency is lost without the key.
Bitcoins were popularized by black market websites specializing in anonymous purchases and have since become accepted currency for online sites including OKCupid and Reddit. Virgin announced it will accept Bitcoins to purchase flights with Virgin Galactic.