The 4K NFT marketplace sells one of its Casascius coins and welcomes Elias Ahonen as its third party Casascius coin authenticator

LOS ANGELES–(BUSINESS WIRE)–, the world’s first marketplace for physically-backed non-fungible tokens (NFTs), just sold a rare unpeeled 1 BTC Casascius coin at 3.5x the face value and added Elias Ahonen as a Casascius coin authenticator.

With only 19,752 unredeemed Casascius coins left, markets for these coins are experiencing high premiums. Prior to 4K offering Casascius coins on their marketplace, prospective buyers would have to search various forums for sellers, ask for references to ensure the seller is legitimate, and either trade in person or send funds ahead of time hoping that the seller will follow through with the trade and that the coin will be authentic. 4K streamlines this process by pre-authenticating each coin, which enables buyers and sellers to trade with confidence. With Elias onboard, 4K now has one of the world’s foremost experts formally signing off on authenticity.

Elias is the author of the Encyclopedia of Physical Bitcoins and Crypto-Currencies and operates, which aims to spread knowledge about these coins. He has been recognized internationally in the media and elsewhere as a subject-matter expert. “As Casascius coins become increasingly recognized as tangible relics of the blockchain revolution and the value of the enclosed BTC rises, authentication becomes all the more important,” says Elias.

There is now a new ungraded Casascius coin listed on the 4K marketplace authenticated by Ahonen. Produced by Mike Caldwell between 2011 and 2013, these coins enable newcomers to the bitcoin community to physically hold bitcoin, which helps overcome mental blocks around the idea of an intangible internet money. Each coin is equipped with a unique private key that is hidden behind a tamper-evident hologram. When peeled, the hologram leaves residue that shows future coin holders that the $BTC has been unloaded. The rarest Casascius coins are gold and contain the private keys to 1000 BTC, making them the most valuable coins in the world valued well above 40 million dollars each.

ABOUT is a protocol that enables humanity to bridge physical assets across digital and analog worlds. By securely storing physical assets and issuing non-fungible tokens (NFTs) that are redeemable for those assets, 4K’s blockchain-based marketplace empowers anyone to seamlessly and confidently buy and sell authenticated assets. For more information, please visit


Max Einhorn