Given the input sentence, please extract the subject and object containing a certain relation in the sentence according to the following relation types, in the format of "relation1: word1, word2; relation2: word3, word4". Relations include: product/material produced; manufacturer; distributed by; industry; position held; original broadcaster; owned by; founded by; distribution format; headquarters location; stock exchange; currency; parent organization; chief executive officer; director/manager; owner of; operator; member of; employer; chairperson; platform; subsidiary; legal form; publisher; developer; brand; business division; location of formation; creator.

In June, we announced that the LUMA Energy, a joint venture between Quanta and Canadian Utilities Limited and ATCO company, was selected by the Puerto Rico Public-Private Partnership Authority for a 15-year operation and maintenance agreement with the Puerto Rico Electric Power Authority, or PREPA, to operate, maintain and modernize PREPA’s more than 18,000-mile electric transmission and distribution system in Puerto Rico.

Answer: subsidiary: ATCO, Canadian Utilities