By Deepa Seetharaman Jan 27 (Reuters) - SoftBank Group Corp (SFTBY, 9984.T) is in talks to invest as much as an additional $30 ​billion in OpenAI (OPAI.PVT), a person familiar with the ‌matter said on Tuesday, as the Japanese conglomerate doubles down on its bet ‌on the ChatGPT owner. The fresh investment would form part of a funding round that could raise up to$100 billion for OpenAI, valuing it at about $830 billion, the person said. Softbank shares rose more than 3% before the bell on Wednesday. ...