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.

They may also be obtained for free by contacting comScore Investor Relations by mail at comScore, Inc., 11950 Democracy Drive, Suite 600, Reston, Virginia 20190, Attention: Investor Relations, by telephone at (310) 279-5980, or by going to comScore's Investor Relations page on its corporate web site at www.comscore.com , or by contacting Rentrak Investor Relations by mail at Rentrak Corporation, 7700 N.E.

Answer: owner_of: comScore, Rentrak