SoftBank Group (9984.JP) is in negotiations to invest up to US$30 billion more in OpenAI, The Wall Street Journal quoted sources as saying. SoftBank Group is already one of the largest shareholders of OpenAI, having invested US$22.5 billion last December, increasing its stake to 11%.OpenAI is seeking to raise up to US$100 billion new capital from investors, and the Company's valuation could reach US$830 billion if it succeeds in raising the full amount.