Summary
Ethereum Layer-2 rollups have created a fragmented liquidity landscape where the same asset trades at different prices across different rollups, creating opportunities for cross-rollup arbitrage. We present the first empirical analysis of swap dynamics and price disparities across major Ethereum rollups, including Arbitrum, Optimism, zkSync, and Polygon. Analyzing over 100 million swap transactions across six months, we find that arbitrage opportunities are persistent and frequent, with an average price discrepancy of 0.3% between rollups for popular trading pairs. We characterize the behavior of arbitrageurs, finding that a small number of addresses capture the majority of arbitrage profits, suggesting increasing professionalization of cross-rollup MEV extraction.