Hitachi Ltd. shares jumped as much as 9.9%, the most since April 10, after the company announced a tie-up with OpenAI, the latest in a growing list of pacts between Japanese tech firms and US artificial intelligence giants. The strategic partnership will involve collaboration on Hitachi’s energy and power grid operations, cooling equipment, storage and its digital solutions hub Lumada, a Hitachi representative told Bloomberg. Hitachi and OpenAI signed a memorandum of understanding on Oct. 2, the Japanese ...