At noon AEST on Monday, the benchmark ASX200 index was down 22.4 points, or 0.3 per cent, at 7,257.1. The broader All Ordinaries was down 26.6 points, or 0.03 per cent, at 7,444.9.
In the US, House Speaker Kevin McCarthy and President Joe Biden were set to meet on Monday to resume negotiations on the US debt ceiling, which have bogged down amid Republican demands to cut spending.
If the ceiling is not raised soon, the world's most powerful nation will begin defaulting on its debts as soon as June 1.
At lunchtime eight of the ASX's 11 sectors were lower with financials the biggest loser, down 0.7 per cent.
All of the Big Four banks were lower with CBA down 1.1 per cent, ANZ dropping 0.9 per cent, Westpac falling 0.6 per cent and NAB down 0.7 per cent.
Insurers were mostly up, however, with QBE rising 1.0 per cent and IAG and Suncorp both 0.5 per cent higher.
The heavyweight mining sector was down 0.4 per cent, although BHP had edged 0.1 per cent higher at $44.19.
Fortescue was down 0.2 per cent and Rio Tinto was basically flat at $109.46.
The energy sector was up one per cent, with Woodside also up one per cent and Santos adding 1.7 per cent.
New Hope was up 2.2 per cent as the coalminer announced underlying April quarter earnings of $448.1m, up 14.8 per cent from the previous quarter and 20.6 per cent from the same quarter last year.
In tech, Bigtincan Holdings was up 7.0 per cent to 53.5c as the AI-powered sales platform announced it had received several confidential takeover offers since engaging with Morgan Stanley to evaluate a potential sale.
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