Northern Star Resources Ltd (NST.AU) saw its stock price plummet by 5% in Monday's trading session following the release of its operational update and forward-looking guidance. The gold miner's shares faced significant selling pressure as investors digested the company's forecasts for the fiscal year 2026 (FY26).

According to the company's announcement, Northern Star expects to sell between 1,700,000 and 1,850,000 ounces of gold in FY26. However, the All-In Sustaining Cost (AISC) guidance for the same period is projected to be in the range of A$2,300 to A$2,700 per ounce. This cost guidance represents a substantial increase from the FY25 revised cost guidance range of A$2,100 to A$2,200 per ounce, potentially squeezing profit margins despite increased production.

Adding to investor concerns, Northern Star disclosed that its exploration expenditure for FY26 is forecast to be approximately A$225 million. While this significant investment in exploration could lead to future growth opportunities, it may also impact short-term profitability. The market's negative reaction suggests that investors are wary of the rising costs and increased spending, despite the company's efforts to boost production. As the gold price environment remains crucial for miners' profitability, Northern Star's ability to manage costs and deliver on its production targets will be closely watched in the coming quarters.