Initially Circle offered OTC (over the counter) crypto services, allowing fait to crypto to fiat transactions, but recently it also acquired crypto exchange Poloniex, allowing for standard exchange trading.
Now the growing startup is raising a $110M Series E, led by strategic partner Bitmain, the world's largest crypto mining company. The round positions Circle as a 'unicorn', approaching the valuations of competing Coinbase and Robinhood.
Along with the funding announcement, Circle has said that it plans to launch Circle USD ("USDC"), an Ethereum-based stablecoin which will be backed by real US dollars. Currently the largest stablecoin in the crypto sphere is Tether, which offers $2.2B of USD-pegged currency, but Tether has been criticized for being unregulated and not transparent.
Circle hopes to offer a regulated solution, meaning it may also need to control the transactions of its token on the Ethereum blockchain to adhere to money laundering law.