Shares of Regis Resources Ltd (RRL.AU) tumbled 5.04% intraday on Friday following the release of its fourth-quarter production report, which revealed a significant jump in all-in sustaining costs.

The gold miner reported Q4 gold production of 101.5 thousand ounces at an all-in sustaining cost (AISC) of A$3,244 per ounce. This marks a notable increase in costs compared to the full-year FY26 AISC of A$2,945 per ounce, raising concerns about margin pressures during the quarter. For the full fiscal year, production totaled 379 thousand ounces.

Separately, the company reported Q4 gold sales of 102.4 thousand ounces, generating total revenue of A$639 million at an average realized price of A$6,241 per ounce. Despite the strong gold price, the elevated quarterly costs appear to have disappointed investors, triggering the sharp intraday decline.