The sharemarket seesawed in early trading before turning lower, as investors took profits in index heavyweight Commonwealth Bank that offset a rally in the iron ore majors.

The benchmark S&P/ASX 200 Index dropped 43.4 points, or 0.5 per cent, to 8554.3 by 12.05pmAEST after resetting its record in the previous session. Eight out of the 11 sectors were trading in the red, led by banking.

Housing developer GemLife opened 5.8 per cent higher on the ASX at midday to trade at $4.40 in the first few minutes of trade.

Investors shrugged off a buoyant Wall Street that overnight saw the S&P 500 reset its record high as President Donald Trump announced that the US had reached a framework trade agreement with Vietnam.

Profit-taking sent the Australian bourse lower with declines in the big four banks led by a 1.6 per cent drop for Commonwealth Bank, while National Australia Bank and Westpac both lost about 1 per cent.

Retailers were also sold off after rallying earlier in the week on hopes of a rate cut by the Reserve Bank of Australia next week. JB Hi-Fi lost 5.6 per cent, Wesfarmers 2.3 per cent, and Harvey Norman 2.8 per cent.

The broader losses were offset by a jump in the iron ore price after Beijing vowed to crack down on disorderly low-price competition and phase out some industrial capacity. That buoyed the mining giants, with index heavyweight BHP jumping 4 per cent, Rio Tinto 1.3 per cent, and Fortescue 0.5 per cent.

Lithium miners also jumped, with Mineral Resources up 6.4 per cent, Pilbara up 7.7 per cent, and Liontown up 4.3 per cent.

Stocks in focus

In corporate news, Pro Medicus jumped more than 10 per cent, at one point reaching a record intraday high of $316.47, before paring gains to be up 6.4 per cent as of midday after announcing it had won two US contracts collectively worth nearly $200 million.

Domino’s Pizza rebounded 2.4 per cent after tanking nearly 16 per cent on Wednesday on the news that chief executive Mark van Dyck would resign in December. Morningstar cut its fair value estimate for the share price by 21 per cent, but said it remains “materially undervalued”.