Northern Star Resources' (ASX:NST) most recent mineral resources and ore reserves update sent mixed signals regarding the quality of its asset portfolio, according to a Wednesday Jarden note.

The company said on Wednesday its estimated mineral resources increased 26% to 88.9 million ounces as of March 31, while its estimated ore reserves jumped 27% to 28.4 million ounces.

The initial resource estimate for the Hemi project was 254 million tonnes at 1.4 grams per tonne grade of gold for 11 million gold ounces, excluding regional deposits, compared to the final estimate published by De Grey Mining in November 2024 of 264 million tonnes at 1.3 g/t gold for 11.2 million ounces, Jarden noted.

Jarden said that although the resource is slightly smaller, the updated estimate is viewed as being of higher quality, driven by changed resource estimation methodology, increased mining dilution assumptions, and updated cost estimates.

The research firm believes that the decline in ore reserves, despite a higher gold price environment, is a "poor outcome."

Jarden maintained its underweight rating on Northern Star Resources and decreased its price target to AU$21.60 from AU$22.30.