Dentsu Soken Inc. shares rose to a record high after the Japanese IT services and consulting firm said it received a buyout proposal from trading house Itochu Corp. at ¥2,880 ($18) per share. The Tokyo-based company supports Itochu’s offer, it said in an announcement on Friday, following a Nikkei newspaper report on the offer. The proposal, made through an Itochu subsidiary, aims to take the company private by acquiring shares from holders other than Dentsu Group Inc.