$25 million MEV brothers case trial invalid: disputes arise again over the boundaries of encryption law.

In November 2025, the highly publicized “MEV Brothers” case was declared a mistrial due to the jury's inability to reach a unanimous verdict. The brothers, who graduated from MIT, were accused of profiting $25 million by manipulating the Ethereum MEV-Boost system within 12 seconds. The core dispute of the case revolves around whether exploiting the design features of blockchain protocols constitutes fraud. Coin Center Executive Director Peter Van Valkenburgh criticized the prosecution's charges as a “significant overreach,” and the outcome of this case will directly affect the U.S. Department of Justice's definition of regulatory boundaries for on-chain activities.

Case Context: 12 Seconds 25 Million Dollars of on-chain Dispute

Anton (25 years old) and James Peraire-Bueno (29 years old) have been charged by the U.S. Attorney for the Southern District of New York with conspiracy to commit wire fraud, wire fraud, and conspiracy to commit money laundering. The indictment states that the two exploited a vulnerability in the MEV-Boost software by monitoring other traders' activities through “transaction poisoning” and then executing a “sandwich attack” to profit $25 million within 12 seconds, seven months after Ethereum's transition to proof of stake in April 2023.

During the three-week trial, the prosecution claimed that the brothers engaged in a typical “bait-and-switch” scam, deceiving users by disguising themselves as legitimate MEV-Boost validators. Meanwhile, the defense attorneys insisted that their actions were akin to “stealing bases in a baseball game,” fully exploiting competitive strategies allowed by the system's design, and did not constitute fraud or conspiracy. This fundamental cognitive divide ultimately led to a deadlock among the jurors. According to Business Insider, some jurors even cried and had sleepless nights during the deliberation process.

The Essence of MEV Technology: The Gray Area and Legal Void of Blockchain

Maximal Extractable Value (MEV) is an intrinsic feature of Ethereum and other proof-of-stake blockchains, referring to the additional profits that validators can obtain by optimizing the order of transactions. In the decentralized finance ecosystem, MEV bots compete with each other to capture arbitrage opportunities, an activity that has been criticized for harming the interests of ordinary users, but is indeed within the bounds allowed by the protocol rules. As Van Valkenburgh emphasized in the amicus brief: “There is no honor among validators; the only expectation is to maximize profits.”

From a technical perspective, the “sandwich attack” implemented by the two brothers is a common MEV strategy: upon detecting a large user transaction, they buy the same asset in advance to drive up the price, and then sell it for profit after the user transaction is completed. This strategy relies on the transparency and predictability of blockchain transactions, while the vulnerabilities in MEV-Boost allow them to peek into transaction information that should have been isolated. Blockchain security expert Chen Dong pointed out: “The uniqueness of this case lies in their active manipulation of the block construction process, rather than passively utilizing public information.”

MEV brother case key facts sorting

• Charges: 3 counts of federal felonies (fraud and money laundering)
• Suspected profit: 25 million USD (within 12 seconds)
• Technical Means: MEV-Boost Exploit
• Attack Type: Sandwich Attack
• Verdict: Jury deadlock results in a mistrial
• Next step: The prosecution decides whether to refile charges.

The Cutting Edge of Crypto Law: Balancing Overregulation and Industry Autonomy

This case forms an interesting contrast with the 2024 Mango Markets manipulation case. In the latter, Avraham Eisenberg was convicted for explicitly admitting to manipulating the market, while the core controversy of the MEV Brothers case revolves around “when actions permitted by the protocol constitute a crime.” Van Valkenburgh warned that if the prosecution ultimately succeeds in convicting, it would “greatly suppress public participation in permissionless networks,” as every on-chain participant could face criminal charges for utilizing the protocol's features.

Legal scholar Professor Wang Lili analyzed: “This case reflects the disconnection between the Web2 legal framework and the realities of Web3 technology. When the idea of code as law encounters traditional financial regulation, the boundaries become blurred.” It is worth noting that Judge Jessica G. Clarke acknowledged during the announcement of the invalid judgment that existing laws indeed face interpretive difficulties when applied to such new types of cases. This judicial modesty may influence the prosecution strategies for similar cases in the future.

Global Regulatory Comparison: Exploring the Legitimization of MEV Activities

Different jurisdictions have different attitudes towards MEV activities. The EU does not explicitly address MEV in the MiCA regulations but includes it under market manipulation regulations; the UK FCA has issued guidance classifying certain MEV strategies as market abuse; Singapore takes a more cautious approach, requiring licensed exchanges to monitor such activities. In Japan, the Financial Services Agency is considering incorporating MEV into the validators' code of conduct, managing it through industry self-regulation rather than criminal prosecution.

Technical solutions are also rapidly evolving. The SUAVE platform developed by Flashbots aims to make MEV competition fairer and more transparent, while trading protocols like CowSwap fundamentally eliminate the possibility of sandwich attacks through batch auction mechanisms. Ethereum core developer Tim Beiko stated that future protocol upgrades will consider limiting MEV extraction capabilities from the consensus layer, but this requires a broad consensus from the community and a balance of technical feasibility.

The Collision Test of Code and Law

The trial of the MEV brothers is not the end of the story, but an important node in the evolution of crypto regulation. When twelve ordinary jurors struggled to map traditional legal terms onto the reality of blockchain technology, it clearly revealed the limitations of the existing legal framework in the digital age. Whether it is the prosecution's insistence on pursuing charges or the industry's outcry, they are essentially delineating the boundaries for on-chain activities in the coming years. In this new world where code and law continue to collide, the MEV case will serve as an important precedent - it concerns not only the fate of two technological geniuses but also how we redefine fairness and fraud in an algorithm-driven economy.