Unlike Bitcoin, which began with no pre-existing units or bootstrapping, Ethereum took a different approach, funding its early marketing and development through an Initial Coin Offering (ICO). Before any ETH was fairly generated and distributed via the mining process, 72.6 million ETH was created, a fact that still remains a highly controversial aspect of Ethereum's origins.
In 2015, 60.1 million ETH was sold during a public crowdfunding event, with contributions mostly made in bitcoin (BTC). An additional 9.1 million ETH was allocated to early contributors, and 3.4 million ETH was assigned to the Ethereum Foundation. Only after the fundraiser was completed did Ethereum enable mining, allowing anyone to participate based on market-determined value for effort, securing the network in the process, and earning ETH through block rewards.
The funds raised through the ICO were instrumental in bootstrapping the Ethereum network, supporting early development, building critical infrastructure, and funding initial research. However, this initial supply creation and distribution, often called a ‘pre-mine’, has been a point of controversy, with some viewing it as essential for Ethereum's success and an ethical means of project funding, while others argue it diverged from the open and accessible ethos championed by the Bitcoin community, unfairly enriching insiders and risking centralisation of control now that network consensus is based on stake.