"Think Smart” yell the billboards across Sydney, Melbourne, Brisbane and Perth. “Tell BHP it’s time for CHANGE.” The slogan is a play on BHP Billiton’s recently unveiled strapline “Think Big”, and the advertising campaign is the latest salvo from activist investor Elliott Advisors, which wants the world’s biggest mining company to shake up its strategy.

Elliott, the New York-based hedge fund founded by Paul Singer, has a history of aggressive campaigns. It brings a “prosecutorial” approach to investing, according to one critic, leaving no tool unturned in its quest to rattle complacent company boards.

The activist’s recent campaigns include Dulux paint maker Akzo Nobel, investment firm Alliance Trust, and manufacturer Arconic; the latter two resulted in the ousting of the firms’ chief executives. Yet Elliott’s fight with BHP, dubbed “The Big Australian” down under, has taken it into uncharted waters.

With the miner set to unveil full-year results later this month, and a new chairman starting in September, speculation is mounting that the fund will push for a board seat – but can it convince fellow investors that its interests align with theirs?