MUMBAI (Reuters) -Investment firm GQG Partners and State Bank of India Mutual Fund are considering investing up to $800 million in total in a $2.16 billion share offering of Indian telecom firm Vodafone Idea, according to two people familiar with the matter. U.S.-based GQG, run by India-born executive Rajiv Jain, plans to invest about $500 million, while SBI Mutual Fund is considering an investment of $200 million to $300 million in the follow-on public offering, said both people, who declined to be named as the plans are confidential. GQG and SBI declined to comment while Vodafone Idea did not respond to queries seeking comment.