The MEV Problem

Maximal Extractable Value — MEV — is one of those topics that starts as a niche technical issue and becomes, the more you understand it, a fundamental challenge for how blockchain-based finance is supposed to work.

The basic idea: whoever controls which transactions get included in a block, and in what order, can extract value that other users aren't aware they're giving up. This was first systematically analyzed in a 2019 paper titled "Flash Boys 2.0," which showed that miners on Ethereum were extracting significant value through transaction reordering and sandwich attacks on DeFi users.

Here's a concrete example. You're trying to buy 100,000 USDC worth of ETH on Uniswap. Your transaction is sitting in the mempool (the public queue of pending transactions) before it's included in a block. A bot watching the mempool sees your large order, buys ETH just before you (moving the price up), lets your order execute at the worse price, and immediately sells into your buy (profiting from the artificial price movement it created). This is a sandwich attack, and it's a rational response to a system where transaction ordering is sold to the highest bidder.

MEV in Ethereum has evolved significantly since the PoW era. Flashbots, a research and development organization, created MEV-Boost — a middleware layer that separates block building from block proposing. Validators don't need to build their own blocks anymore; they can receive pre-built blocks from specialized "block builders" and collect most of the MEV value. The block builder market has become highly competitive and concentrated, with a small number of builders handling most blocks.

This doesn't eliminate MEV; it redistributes it. Validators now capture most of the MEV value through block builder payments. The net effect on users is that MEV extraction becomes more efficient and systematic rather than less. For retail DeFi users, sandwich attacks and arbitrage continue.

PBS (Proposer-Builder Separation) is Ethereum's longer-term architectural solution — enshrining the separation at the protocol level rather than through voluntary adoption of Flashbots middleware. The current MEV-Boost setup is a temporary workaround.

The deeper problem is that some MEV is technically unavoidable in any system with public transaction ordering. Arbitrage MEV — which brings prices on different exchanges into alignment — is actually beneficial; it makes markets more efficient. "Bad" MEV like sandwich attacks and liquidation exploitation is more clearly harmful to users. Separating the two and finding protocol-level solutions to reduce harmful MEV without harming beneficial arbitrage is an active area of Ethereum research. Solutions like encrypted mempools (where transactions are hidden until finalized) are promising but introduce their own tradeoffs.

MEV matters for the global settlement layer thesis because it represents a form of systematic wealth extraction from users that doesn't exist in traditional financial markets (or exists in different and regulated forms). If Ethereum-based finance is going to compete with or replace traditional financial infrastructure, it needs answers to MEV that scale to institutional participation levels.

// COMMENTS

ON THIS PAGE