AdvertisementSKIP ADVERTISEMENTThe funding round would double the value of the start-up behind ChatGPT and establish it as the world’s most valuable private company.Sam Altman, OpenAI’s chief executive, speaking at Salesforce’s Dreamforce conference in San Francisco on Tuesday. His company is planning an I.P.O. in 2027.Credit...Benjamin Fanjoy/Getty ImagesSept. 16, 2026, 12:01 a.m. ETOpenAI is considering a new funding round that would value the giant artificial intelligence start-up at about $1...