A preliminary Federal Court ruling over journalist privilege has lifted the curtain on a potentially explosive defamation claim involving allegations of insider trading, social media stars, and the unmasking of a corporate broker who passed information to a sharemarket commentator.

Alan Davison, better known by his pseudonymous Twitter profile Stock Swami, is being sued by mining executive and capital markets deal-maker Tolga Kumova, for defamation over six tweets accusing Mr Kumova of insider trading, misleading the market, and the provision of inside information about New Century Resource’s planned acquisition of the Goro Nickel Mine.