Rumors about the crypto exchange Poloniex sale have been officially confirmed. The cryptocurrency financial company Circle is the buyer who acquired one of the largest North American crypto-exchanges.

Circle and Poloniex published official statements, saying that they will work together to bring more efficient, broad and high-quality services to their customers.

Officially the amount paid for Poloniex is not disclosed, but according to the anonymous sources of Fortune, Circle paid about $400 million for the crypto-exchange.

"We’re proud to announce that Circle has extended its commitment to a new vision for global finance by acquiring Poloniex, a leading token exchange platform," Circle's statement says.

Circle uncovered what innovations Poloniex could soon adopt. Among possible future improvements is more wide fiat currency support, market expansion, including new tokens in the listing and a significant improvement in the customers support service.

"We are excited to announce that as of today, February 26, Poloniex will be joining the Circle team and building on our foundations to further the scale of our platform, grow our global reach, and accelerate the token ecosystem in the months and years ahead," Poloniex said in a statement.

The rumors about a possible deal between Poloniex and Circle first appeared on 2 February in the blog of Ken Kearson, former chief editor of the New York Observer. Then, the representative of Circle refused to confirm this information, as well as to refute it, citing the fact that he is on a business trip.

The Boston-based Circle offers cryptocurrency-related services either to retail or institutional investors. Circle Trade is the largest in the US over-the-counter platform for crypto-currency trading. In a month, it processes transactions with virtual currencies worth more than $2 billion with a minimum transaction size of $250,000.

Circle was founded in 2013 and received financing from the major US bank Goldman Sachs, Chinese Internet giant Baidu and venture capitalist Jim Breyer. After the last round of financing, that took place in June 2016; Circle was valued at $480 million.

Delaware-based Poloniex is the 18th cryptocurrency exchange in the world by trading volume. It lists 68 cryptocurrencies. Recently, Poloniex has faced problems caused by a sharp increase in customers. Users complained about problems with withdrawing funds and replenishment of deposits, erroneous account bans, and weak support service.

Acquiring Poloniex, Circle turns into a serious competitor to the largest exchanges of the country, such as Coinbase, Bittrex, and Kraken.