Tim Roberts is one of three children of the late John Roberts, who was the founder of construction company Multiplex. Since 2007, when the Roberts family (including his brother Andrew Roberts and sister Denby Macgregor) sold out of Multiplex, he has led a private investment group through his family office. Warburton Group has interests in equities, hedge funds, infrastructure, property, aviation, fishing and aquaculture, domestically and internationally. Mr Roberts joined the board of ASX-listed Mineral Resources in November 2016. He has also served on the boards of Crown Resorts Perth and the Perth Symphony Orchestra, which he became patron of in 2018. Mr Roberts is a member of the board of trustees of the Telethon Institute, and patron of North Cottesloe Surf Lifesaving Club. He was an executive director of Multiplex Group from 2003 to 2007, before the company was bought by Brookfield Asset Management. A significant private business of his has been selling corporate aircraft, notably for Bombardier.