WA Super chief executive John McNally said the appointment of Towers Watson followed a "rigorous selection process".
"We chose Towers Watson as the most suitable partner to provide investment consulting given their global research coverage, thought leadership and alignment in assisting the trustee in delivering investment outcomes for members," Mr McNally said.
Towers Watson head of Australian investment Graeme Miller said there is a "strong cultural and philosophical alignment" between WA Super and Towers Watson.
"We are very pleased to have been appointed ... and look forward to the prospect of working closely and partnering with WA Super," Mr Miller said.
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