Becoming Immutable: How Ethereum is Made

We collect and study 15,097 blocks proposed for inclusion in the Ethereum blockchain during 8 minutes on December 3rd, 2024, corresponding to 39 added blocks. These proposed blocks contain 10,793 unique transactions, and 2,380,014 transaction-block pairings, our primary unit of analysis. We find that 20% of user transactions are delayed: although proposed during a bidding cycle, they are not included in the corresponding winning block. Approximately 30% of such delayed transactions are exclusive to a losing builder. We also identify two arbitrage bots trading between decentralized (DEX) and centralized exchanges (CEX), which are responsible for a significant fraction of the value of proposed blocks. By examining their bidding dynamics, we estimate that the implied price at which these bots trade USDC/WETH and USDT/WETH on CEXes is approximately 2.8 basis points better than the contemporaneous Binance price.