The Independent Electricity System Operator (IESO) is the Crown corporation responsible for operating the electricity market and directing the operation of the bulk electrical system in the province of Ontario, Canada. It is one of seven Independent System Operators in North America. The IMO was renamed to the IESO in January 2005 as a result of the passage of Bill 100, which redefined the direction of deregulation and also led to the creation of the Ontario Power Authority. As of January 1, 2015 the IESO and the Ontario Power Authority were merged.