Sigmapool.

Sigmapool is a 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 Bitcoin, Litecoin and several smaller coins. It began in 2018 with Litecoin and found its first Bitcoin block on 22 November 2018. Its site is in five languages, Russian first. Its terms name the company behind it as Sigmapool Project Management, in Dubai; in 2020 and 2021 they named Sibhash Pte. Ltd., a company in Singapore. Neither names any person.

It pays miners a set amount for their work, whether or not it finds a block: by pay per share, or PPS, and from 2019 also by full pay per share, or FPPS, which adds a share of the fees. Each Sigmapool block paid its whole reward to one of the pool’s addresses. That reward is separate from the transactions confirmed inside the block.

Its Bitcoin blocks came in two runs, from November 2018 to April 2019 and from June 2020 to 5 February 2022, its last. The pool still runs, but no block has carried its name since then, and no explanation from the pool was found. In 2024 the researcher 0xB10C found that its Bitcoin mining server was handing miners work from SECPOOL, so the blocks they found carried SECPOOL’s name; he called them “two names, but probably one pool”. He counts both among the pools he calls “AntPool & friends”, while noting it isn’t proven that one company runs them all.