Bitfinex
Bitfinex is a cryptocurrency trading platform, owned and operated by iFinex Inc. which is headquartered in Hong Kong and registered in the British Virgin Islands.In 2015 the exchange's customers were hacked, losing about $400,000, and in 2016 about $73 million more was stolen from its customers' accounts. The exchange's access to U.S. dollar payments and withdrawals has been curtailed.
Research suggests that price manipulation of bitcoin on Bitfinex accounted for about half of the price increase for bitcoin in late 2017.