The S&P gave back early gains from a record high of 7417.6 points to finish flat on the day at 7394 points as investors shrugged off speculation Sydney’s lockdown will knock 2.4 per cent off GDP in the September quarter.

The materials sector was the best performer, finishing up 1 per cent with mining heavyweights BHP Billiton, Rio Tinto, Fortescue and Mineral Resources all advancing. BHP shares hit a new record high of $52.19, before giving back some gains to finish up 1.25 per cent at $51.91.