India, Oct. 6 -- Energy company Emera Inc. (EMA.TO) and Canadian Utilities Ltd. (CU.TO), a subsidiary of ATCO Ltd. (ACO.X), Tuesday said they have agreed to combine in an all-share merger of equals, creating a utility and energy infrastructure company with a pro forma enterprise value of about C$72 billion.

Valued at an implied enterprise value of about C$28 billion for Canadian Utilities, the deal would be the largest merger in Canadian history and create a Top 20 North American utility.

The combined company, which will operate as Emera, is expected to have about C$45 billion in rate base and serve six million customers across Canada, the U.S. and international markets. About 95% of earnings are expected to come from regulated utilities,...