The superannuation industry will grow to be worth $13.6 trillion by 2048 – or 176 per cent of Australia’s GDP – but a continuously shrinking number of funds will control the nation’s retirement pool as “big super” cements its influence over the economy.

A new report by financial services company Mercer predicts just 77 super funds will exist within four years, down from 107 now and 232 in 2015.