Mumbai: The Adani Group is planning to raise at least $1 billion through the sale of equity to fund the takeover of two Mumbai airports from GVK Group, said people with knowledge of the matter.The conglomerate is currently in talks with about four global wealth funds, including Qatar Investment Authority (QIA) — a partner in Adani Electricity— as well as a Canadian and a Singapore-based fund. Adani Airport Holdings will likely sell a 10-20% holding to raise the funds, said the people cited above. QIA could be a frontrunner, they said.