Two unnamed Bitcoin mining pools have jointly surpassed 51% of the cryptocurrency’s global hash rate, according to data cited by industry commentators on 19 Aug. The concentration gives the pair—believed by some participants to include AntPool—technical power to reorganize blocks, reverse or block transactions and potentially mint counterfeit bitcoin, a scenario commonly referred to as a 51% attack. It is the first time in more than a decade that any combination of pools has held majority control. The last instance was in 2014, when GHash.io briefly crossed the threshold before voluntarily reducing its capacity after industry backlash. The new concentration has revived long-standing debate over centralization risks in what is marketed as a decentralized network. Critics warn that sustained majority control could erode trust in Bitcoin’s ledger and price stability, while others argue that the thousands of individual miners behind the pools have diverging interests and would abandon any pool that attempted to manipulate the chain. AntPool’s parent firm Bitmain has historically reported partial ownership by Chinese state-affiliated entities, adding geopolitical sensitivity to the development. As of late Tuesday, no irregularities had been observed on the Bitcoin blockchain, and the pools involved had not commented publicly on their intentions.