The company was spun out of BHP in May 2015 as the Anglo-Australian giant looked to slim down its portfolio. Its shares have since outperformed its former parent, and it announced a maiden interim dividend in February. Its stock slipped 3.2pc in morning trade. Analysts at Investec said the decision was "disappointing for South32, given the obvious synergies, but a comforting indication that miners are remaining disciplined".