MEV and On-chain Arbitrage: Simplified

By Mishal Alexander | Learn you a new crypto knowledge | 17 Oct 2022

Understanding On-Chain Arbitrage and MEV

On-chain arbitrage is a crucial concept in decentralized finance (DeFi) that leverages price discrepancies across various liquidity pools. This process is intricately linked to the notion of Miner Extractable Value (MEV), which refers to the maximum profit miners can extract from reordering, including, or excluding transactions within a block.

What is MEV?

MEV, originally termed "Miner Extractable Value" and now frequently referred to as "Maximum Extractable Value," represents the potential profit miners can earn by manipulating transaction order. Transactions are held in a mempool until miners verify and pack them into blocks. By deploying specialized bots, traders can identify profitable opportunities based on anticipated price movements in automated market maker (AMM) pools.

MEV bots capitalize on their ability to influence transaction ordering, allowing them to prioritize trades that maximize their profits. Despite attempts to enhance order fairness in blockchain transactions, these efforts have seen limited success.

The Evolution of MEV

The concept of MEV was first noted by an algorithmic trader known as Pmcgoohan in 2014, even before Ethereum's launch. He recognized that miners could exploit their control over transaction inclusion and ordering to benefit at the expense of unsuspecting users. This issue gained wider attention with the publication of *Flash Boys 2.0* in 2019, which formally introduced the term "MEV." Subsequent works like Ethereum is a Dark Forest by Georgios Konstantopoulos & Dan Robinson and Escaping the Dark Forest by Samczsun further solidified MEV's significance within crypto-economics, highlighting its real-world implications for Ethereum users.

MEV is often described as an "invisible tax," representing the maximum value miners can extract from transaction manipulation.

Arbitrage Opportunities in DeFi

Arbitrage traditionally involves buying low in one market and selling high in another. In DeFi, this principle applies across various liquidity pools that may not communicate with each other, creating opportunities for profit through price discrepancies.

For example, if a user sells $5 million worth of WETH in a Uniswap pool, the increased supply may lead to a lower price for WETH compared to other platforms like Sushiswap. A savvy trader could then buy WETH on Uniswap and sell it on Sushiswap for a profit.

DeFi introduces an additional layer of complexity through atomic transactions. These allow users to execute multiple operations within a single transaction as long as the final state is valid. Flash loans enable users to borrow large amounts without upfront capital, facilitating arbitrage opportunities even for those with limited resources.

The Mechanics of On-Chain Arbitrage

To illustrate how on-chain arbitrage works, consider an AMM pool where users trade WETH and USDT. The pool operates under the "Uniswap invariant," which maintains that the product of reserves (X and Y) remains constant:

$$
x * y = z
$$

By rearranging this equation, traders can determine expected outputs for specific inputs when executing trades across different pools.

In practice, if Pool A allows purchasing WETH at a lower price than Pool B offers for selling it, traders can execute a series of swaps to maximize their returns. The goal is to achieve:

$$
e > 0
$$

where $$ e $$ represents the profit from these transactions.

The Role of Bots in Arbitrage

Arbitrage bots play a pivotal role in capitalizing on these opportunities. For instance, a bot connected to the mempool listens for transactions that signal potential arbitrage opportunities. Once identified, it calculates the optimal strategy and submits its own transaction for inclusion in the same block—a process known as "back running."

To successfully back run a transaction, bots must replicate gas prices from original transactions to ensure priority inclusion in the block.

Challenges and Risks Associated with MEV

While exploring MEV presents intriguing opportunities, it also comes with significant risks. The DeFi landscape resembles a "wild west," where malicious actors deploy traps to exploit unsuspecting traders. One common tactic is the "sandwich attack," where an MEV bot inflates token prices before an unsuspecting buyer enters the market, allowing the bot to profit at the buyer's expense.

Data from Flashbots indicates that substantial amounts—over $7 million—have been extracted through MEV activities on Ethereum alone within recent months. Although Ethereum is particularly susceptible due to its longer block times and high fees, other platforms like Compound and Aave also experience similar risks related to liquidation front-running.

Conclusion

On-chain arbitrage represents both an opportunity and a challenge within the DeFi ecosystem. As liquidity continues to grow and trading volumes increase, understanding MEV dynamics becomes essential for participants aiming to navigate this complex landscape effectively. Traders must remain vigilant against predatory practices while seeking out profitable arbitrage opportunities amidst evolving market conditions.