OpenAI and SoftBank Group Corp. have jointly invested $1 billion in SB Energy, an infrastructure company that’s working with the tech firms on a massive US buildout of data centers to power artificial intelligence.OpenAI and SoftBank will each invest $500 million in SB Energy to support the energy firm’s growth as a data center developer and operator, the companies said in a statement Friday. OpenAI also said it has selected SB Energy to build and operate its 1.2 gigawatt data center in Milam Co...