Fidelity Digital Assets, part of one of the most prominent asset managers in the world, Fidelity Investments, announced this week it will offer Ethereum Ethereum Ethereum is an open source, blockchain-based distributed computing platform and operating system featuring smart contract functionality. Created in 2014, Ethereum now stands as the second largest cryptocurrency by market cap at the time of writing.As a decentralized cryptocurrency network and software platform, Ethereum represents the most prominent altcoin.