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Stock Markets February 6, 2026

NexGen Shares Slide After Short Seller Questions Rook I Valuation and Production Case

Culper Research says the Rook I project's NPV is substantially overstated and peak output targets are 'impossible to achieve,' prompting a sharp stock decline

By Marcus Reed NXE
NexGen Shares Slide After Short Seller Questions Rook I Valuation and Production Case
NXE

NexGen Energy Ltd. shares fell 10.5% after short seller Culper Research disclosed a short position and published a critique alleging the Rook I project's net present value is overstated by 43% to 62% and that the company's 29.7 million-pound peak annual production forecast is "impossible to achieve." The report also contests geological continuity in the high-grade A2-HG zone, flags higher-than-reported capital requirements, highlights executive payouts, and notes frequent CFO turnover.

Key Points

  • NexGen shares dropped 10.5% after Culper Research announced a short position and published detailed allegations.
  • Culper claims the Rook I project's NPV is overstated by 43% to 62% and calls the 29.7 million-pound peak production forecast "impossible to achieve."
  • The short seller raises concerns about deposit continuity in the A2-HG zone, capital cost and schedule underestimates, executive payouts exceeding C$140 million, and frequent CFO turnover.

NexGen Energy Ltd. stock fell 10.5% on Friday after a short seller announced a position in the company and released a detailed critique of its flagship Rook I project in Saskatchewan's Athabasca basin.

In a report disseminated on social media, Culper Research argued that NexGen has overstated the net present value of Rook I by between 43% and 62%. The firm further contended that the project’s projected peak annual uranium production of 29.7 million pounds is "impossible to achieve."

Culper questioned the characterization of the deposit, focusing on the A2-HG zone that NexGen presents as the project's dominant high-grade area. That zone is said to account for 68% of the project's total metal, but the short seller maintains it is not as "thick" and "continuous" as NexGen portrays. Culper says this discrepancy undercuts the C$6.3 billion NPV figure NexGen has assigned to Rook I.

The report also scrutinized NexGen’s cost and schedule assumptions. While NexGen recently updated its capital plan to double its pre-production capital expenditure estimate from $1.1 billion to $2.2 billion, Culper argued that capital costs and construction timelines remain "materially understated."

Alongside technical and financial criticisms, Culper characterized NexGen as "an insider enrichment vehicle masquerading as a uranium development company," citing named executives who the firm says have received more than C$140 million in total payouts over the past decade, including C$78.5 million to the chief executive.

The short seller also pointed to executive turnover as a concern, highlighting that NexGen has cycled through seven chief financial officers since 2012. Culper further noted that several key personnel involved in the original Arrow deposit discovery have departed for smaller mining firms.

NexGen, which has not yet generated revenue, continues to develop the Rook I project, which the company describes as "the world’s most strategic uranium asset." The dispute over resource geometry, capital requirements, management track record, and executive compensation has now coincided with a notable move in the company's share price.

Market participants will likely watch for any formal response from NexGen and for further developments that could corroborate or rebut the technical and financial claims in the short seller's report. For now, the allegations have translated into immediate market reaction and added scrutiny on project valuation and execution risk.

Risks

  • Valuation risk: If the claims about an overstated NPV and less continuous high-grade zones are correct, investors face potential downward revisions to project valuation - impacting mining and resource investment sectors.
  • Execution and cost risk: Allegations that capital costs and construction timelines remain "materially understated" imply the potential for further increases in capital expenditure and schedule slippage - affecting project finance and construction contractors tied to mining developments.
  • Governance and personnel risk: Frequent CFO turnover and departures of key discovery team members, combined with large executive payouts, raise questions about corporate governance and management continuity - relevant to investors and service providers in the mining and capital markets sectors.

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