Northern Star Resources Shares Down 31% in Two Weeks: Why The Sentiment Shift?

Northern Star Resources shares (ASX: NST) have suffered a dramatic collapse in market confidence, with shares closing 18.75% lower at A$21.75 into the weekend, marking the stock’s lowest point of 2026 and capping a brutal 31.45% decline from its 2 March close in less than a fortnight. Having earlier rallied strongly, what is behind the sudden shift in sentiment at NST?

The Norther Star share price hit the new 2026 low following an operational update that rattled markets already nervous about the company’s execution capability. The shares now sit 10.97% lower year-to-date, a remarkable reversal for a name that remains 25.07% higher over the past twelve months. That twelve-month comparison underscores just how violent the recent selloff has been, erasing months of gains built on optimism around higher gold prices and the company’s flagship expansion project at Kalgoorlie.

Guidance trimmed, and not for the first time

The severity of today’s move reflects mounting frustration with Northern Star’s guidance trajectory. Markets had already digested a production downgrade in early January, when management cut full-year expectations from 1.7-1.85 million ounces to 1.6-1.7 million ounces. Today’s update effectively delivered a second blow, suggesting even the lower end of that revised range may prove elusive.

Northern Star’s latest operational disclosure revealed that achieving the bottom of its already-reduced FY 2026 production guidance will be “challenging.” Management now expects full-year output to come in “above 1.5 million ounces”; language that markets interpreted as a soft downgrade to approximately 1.5-1.6 million ounces, well below the 1.6-1.7 million ounce range reaffirmed just ten weeks ago.

The company reported total gold sales of 220,000 ounces for January and February combined, a run rate that implies significant improvement will be needed in the second half to reach even the lowered expectations. The underperformance stems from two key operational headaches: weaker-than-planned milling performance at the KCGM operation in Kalgoorlie and reduced mining productivity across several sites, particularly at the Jundee mine.

Management explicitly noted that the final FY 2026 outcome “will depend heavily on mill throughput at KCGM, which continues to be highly variable.” That dependency is particularly concerning given the existing mill’s inconsistent performance and the fact that Northern Star’s major growth catalyst, the KCGM Mill Expansion Project, won’t come online until early FY 2027.

The A$1.5 billion expansion project remains on schedule for commissioning between July 2026 and June 2027, according to the company. To protect that timeline, Northern Star has increased labour on site, with approximately 800 contractors currently working on the plant itself and another 400 completing enabling works. The decision to add labour suggests management is willing to accept higher near-term costs to avoid delays on a project that underpins the company’s medium-term growth thesis.

Northern Star’s half-year results to 31 December 2025, released in mid-February, had shown EBITDA surging roughly 34% year-on-year on the back of stronger gold prices, despite softer volumes. The company maintained a strong balance sheet with net cash and declared a fully franked interim dividend of 25 cents per share. Those results, combined with the company’s impending inclusion in the S&P/ASX 20 Index on 23 March, had fuelled optimism through early March and pushed the stock above A$31.

What comes next for Northern Star?

The timing of the selloff is particularly painful for Northern Star given the positive sentiment that had built through February and early March. Broker Jefferies had lifted its price target to A$35 with a Buy rating when the stock was trading around A$28-29, highlighting the company’s leverage to gold prices and the potential for re-rating as the KCGM expansion neared completion. Consensus analyst ratings sat around Buy with a median target near A$30.33.

That constructive view has now been thrown into doubt. The pattern of successive guidance reductions; first in January, now effectively again in March, damages management credibility and raises questions about whether operational challenges at KCGM and Jundee are transitory or structural in nature. Markets are likely to demand a larger risk premium until Northern Star can demonstrate consistent delivery against expectations.

The broader market backdrop has amplified the stock-specific pain. Australian equities have endured a volatile week, with the benchmark index posting its lowest weekly close since December amid geopolitical tensions, rising oil prices, and expectations of a Reserve Bank of Australia rate hike. In that risk-off environment, high-multiple growth names with execution concerns tend to be punished more severely.

The question for value-oriented investors is whether the selloff has created a buying opportunity or whether further downgrades loom. The answer likely hinges on whether KCGM’s milling performance stabilises in coming months and whether the expanded mill delivers on its promise when commissioned next financial year.

Northern Star’s resource base of more than 70 million ounces and diversified portfolio of long-life assets remain intact, as does the structural tailwind from elevated gold prices. The company’s inclusion in the ASX 20 will bring mechanical buying from index funds and increased institutional ownership. However, markets will need evidence that management can execute on operational plans before rewarding the stock with a premium multiple again, leaving Northern Star facing a credibility rebuild even as its long-term fundamentals remain sound.