US-based boutique investment firm GQG Partners has invested $1.1 billion in Adani Power for an 8.1 per cent stake, sources with knowledge of the matter said on Wednesday. GQG Partners bought 31 crore shares of Adani Power in the largest ever secondary markt equity deal, they said, adding that promoter Adani family sold the stake for over Rs 9,000 crore ($1.1 billion).