Culper Research has announced a short position on Ethereum (ETH) and related securities, including BMNR, citing concerns over the token's economic model following the December 2025 Fusaka upgrade. The firm claims the upgrade increased block space, leading to a 90% drop in gas fees and a surge in address poisoning and dusting transactions, which artificially inflate on-chain activity. Additionally, staking rewards have reportedly decreased, weakening validator incentives. Culper Research also notes that Ethereum's market share is being eroded by Solana and Layer 2 networks.