Culper Research Bets Against Ethereum and BitMine Amid Concerns Over 'Fusaka' Upgrade

Short seller Culper Research has released a report expressing skepticism about ether (ETH) and BitMine (BMNR). According to NS3.AI, the report argues that Ethereum's 'Fusaka' upgrade in December 2025 has significantly reduced fees by approximately 90%, negatively impacting ETH tokenomics and undermining the bullish network metrics promoted by BitMine chairman Tom Lee. Culper Research suggests that the reduction in fees is compressing staking yields, which could potentially lead to a 'death spiral' characterized by decreased validator demand and weakened network security. Additionally, the report highlights that Ethereum co-founder Vitalik Buterin has sold nearly 20,000 ETH. It also estimates that BitMine's treasury of 4.4 million ETH is about 45% underwater, with unrealized losses amounting to approximately $7.4 billion.