Rain AI, a San Francisco-based chip startup backed by OpenAI CEO Sam Altman, is exploring a sale after its ambitious $150 million Series B funding round failed to secure investors. Despite early backing from Altman in a $25 million seed round in 2022, Rain AI has struggled to convert technical ambition into scalable business outcomes. The company, which aimed to rival industry giants like Nvidia (NASDAQ:NVDA) with its energy-efficient chips, is now in discussions with potential buyers, including