UltimusPool.

UltimusPool was a Bitcoin mining poolMining poolA group of miners who share the work of finding blocks and split the rewards, so each gets paid steadily instead of rarely. for professional miners. It found its first block, 710,564, on 20 November 2021 and its last, 968,574, on 25 September 2026, and it closed on 22 October 2026, when it stopped taking miners’ work. Its website named no company, people or address. When Binance announced a partnership with the pool in 2022, it named Sofia Li as UltimusPool’s chief executive.

UltimusPool paid its miners by full pay per share, or FPPS: a set amount for the work they sent, paid daily, whether or not the pool found a block. So each UltimusPool block’s first transaction pays the reward to the pool’s own address, and the pool paid its miners separately. These are payments to the pool’s miners, separate from the transactions confirmed inside the block.

In June 2022 Binance Pool, the Binance exchange’s mining pool, announced UltimusPool as its “technical services provider”. UltimusPool called itself “a key strategic business partner of the Binance Pool”. On 13 October 2026 Binance said it would close Binance Pool too, on 10 November.

Researchers link UltimusPool to AntPool. TheMinerMag found its block rewards being moved together with AntPool’s from 2022, and in 2024 mempool.space’s mononaut reported that one custodian, a firm that holds bitcoin for others, controlled both pools’ reward addresses. He also saw UltimusPool often send its miners the same draft blocks, or templates, as AntPool. In December 2024 and March 2025 the researcher 0xB10C saw UltimusPool, AntPool, Braiins, Poolin and Binance Pool send miners the same invalid work, for blocks that would have paid out more than Bitcoin’s rules allow, and took it as a further sign that one entity operates them. He calls the group “AntPool & friends”, while noting that which pools belong can only be assumed. UltimusPool didn’t say what the arrangement was.