Wall Street swung between gains and losses ahead of today’s expiration of options and futures, a quarterly event that usually brings increased volume and volatility. Iron ore prices continued to fall, dragging on the US shares of mining giants BHP and Rio Tinto and setting the Australian sharemarket up for a weak start.

The S&P 500 fluctuated on either side of unchanged after the index posted its biggest gain since August on Wednesday, and closed 0.2 per cent lower at 4473.75 points. The equity market benchmark is down about 1 per cent so far this month amid concern about a broader pullback in the wake of a string of record gains. The Dow Jones Industrial Average also dropped 0.2 per cent, while the Nasdaq edged up 0.1 per cent.

The lack of direction on Wall Street and the iron ore’s slump are set to make for a soft open at the local bourse. ASX futures were down 20 points, or 0.3 per cent, at 7422 as of 6:46am AEST. The US-traded shares of BHP fell 3.6 per cent and Rio’s stock tumbled 4.6 per cent as the iron ore price extended its recent slide, falling by a further 8.1 per cent to $US107.21 per tonne.

Technology companies weakened, along with communications and health care stocks. Nvidia fell 0.4 per cent and Facebook fell 0.2 per cent.

“After seven months of gains, equity markets have been choppier mid-way through September,” said Keith Lerner, chief market strategist at Truist Advisory Services. “This is actually quite normal from a historical seasonal standpoint, though the ongoing carousel of concerns continues.”

Losses for banks were tempered by rising bond yields that help them charge more lucrative interest on loans. The yield on the 10-year Treasury rose to 1.34 per cent from 1.30 per cent late Wednesday.

US indices began fluctuating as investors weighed the impact of mixed economic data on the Federal Reserve’s plans to taper stimulus.

Retail sales unexpectedly increased in August, suggesting that demand for goods remains strong. Consumers simply shifted spending to more online purchases and away from businesses that are still struggling to recover from the pandemic, including restaurants and other business that rely on in-person spending.

Wall Street was also reviewing a disappointing report showing that weekly unemployment claims rose more than expected.