End-of-day summary:
The share market's winning streak ended at seven after a dour trading update from Westpac and slump in oil weighed on bank and energy stocks.
The ASX 200 declined 80 points or 0.97% to its biggest loss in more than three weeks.
The energy sector skidded 2.89% as oil prices reacted to a weekend decision by the OPEC+ cartel to raise production. Brent crude dived 3.7% this afternoon to US$59.09 a barrel.
The big four banks shed between 0.99% and 2.99% after Westpac missed half-year profit expectations. The day's winners included gold miners and some healthcare companies.
Wall Street's own winning run - the longest since 2004 - could also be in peril tonight following a slide in stock futures. S&P 500 futures declined 0.7% this afternoon as oil prices wilted. On Friday, the S&P 500 climbed 1.47% to a ninth straight gain.
