Two recently-listed commodity groups are to join Britain’s FTSE 100 after the latest quarterly indexes shuffle, FTSE Group said on Wednesday, reflecting strong investor interest in resource-linked stocks. India-focused oil & gas group Essar Energy and gold miner African Barrick Gold (ABG), which both floated in London earlier this year after being spun out of international parents, will join the blue-chip index from the start of business on Monday, June 21.