Gina Rinehart has emerged as a big shareholder in Lynas Rare Earths after a $49 million spending spree on the resources stock over the past few days.

Mrs Rinehart’s Hancock Prospecting lifted its stake in Lynas, the world’s biggest non-China producer of rare earths, to 5.82 per cent on Tuesday. The share raid has fuelled speculation Australia’s richest person may emerge as a kingmaker in any rare earths mega-merger between Lynas and New York-listed MP Materials.