Australia’s sharemarket experienced a notable decline on Friday, as a significant cost overrun at BHP’s Jansen potash project and ongoing geopolitical uncertainties weighed heavily on investor sentiment. The S&P/ASX 200 index dropped 82.4 points, or 0.92 percent, to close at 8,828.7, while the broader All Ordinaries index decreased 79.5 points, or 0.87 percent, ending the session at 9,047.3. Despite the downturn on the day, the benchmark index registered a slight gain of just under 0.3 percent for the week.

Materials stocks led the losses, declining by 4 percent, with BHP—Australia’s largest company—suffering the steepest single-day fall since April 2025. The mining giant’s shares slipped 5.6 percent to $61.40 after it revealed that the estimated cost for its Canadian Jansen potash project had escalated to approximately US$6.9 billion, including contingencies. This figure represents a substantial increase from the initial budget of US$4.9 billion, prompting investor concern over the project's financial outlook.

Other mining companies, including those involved in uranium, aluminium, metals, and gold, also faced downward pressure. Deep Yellow, a uranium miner, was the worst performer on the ASX 200, falling 9.88 percent to $1.55. Aluminium producer Alcoa declined 6.87 percent to $83.14 as commodity prices remained under strain.

In contrast, sectors such as healthcare and information technology provided some relief. 4D Medical's shares rose 17.6 percent to $4.54, while Life360, a location-sharing safety app, gained 6.19 percent to close at $23.84. Energy stocks showed mixed results: Woodside advanced 14.3 percent to $29.03, supported by rising oil prices, whereas Santos and Ampol slipped 0.4 percent and 0.6 percent respectively.

Oil markets saw Brent crude prices climb by US$1 to reach US$77 per barrel. This followed earlier declines linked to a recent peace agreement between the United States and Iran, which briefly increased expectations that oil flow through the strategic Strait of Hormuz could normalize after disruptions. However, concerns remain regarding the impact of sea mines on shipping traffic, a factor that analysts say could delay a full recovery of oil transit volumes. John Oh, an energy and sustainable economist at Commonwealth Bank, highlighted this ongoing uncertainty, while Global X’s senior investment strategist Marc Jocum attributed Friday’s sharemarket fall to a combination of geopolitical tensions, weakness in commodity prices, and worries about global economic growth.

In corporate developments, SkyCity shares surged 14.63 percent to 47 cents after the entertainment company disclosed it had agreed to a $2 million payment, spread over three installments, in relation to breaches of anti-money-laundering and harm-minimisation regulations. Meanwhile, education services provider IDP increased 6.7 percent to $2.56 following a positive trading update.

Asian markets closed mixed on Friday, with Japan’s Nikkei index rising 0.3 percent, while South Korea’s KOSPI modestly declined by 0.13 percent.