NioCorp Developments Ltd美股招股说明书(2025-09-29版)

7,004,740 Common Shares2,755,260 Pre-Funded Warrants to Purchase 2,755,260 Common Shares We are offering 7,004,740 of our common shares, without par value (“Common Shares”), and, in lieu of Common Shares tocertain investors that so choose, 2,755,260 pre-funded warrants to purchase an aggregate of 2,755,260 Common Shares (the “Pre-Funded Warrants”). The purchase price of each Pre-Funded Warrant will equal the price per share at which each Common Share issold to the public in this offering, minus $0.0001, which is the exercise price of each Pre-Funded Warrant. The Pre-Funded Warrantswill not have an expiration date and will be immediately exercisable. The public offering price for each Common Share is $6.15. Thisprospectus supplement also relates to the offering of Common Shares issuable upon exercise of the Pre-Funded Warrants. TheCommon Shares and Pre-Funded Warrants are being sold on a “reasonable best efforts” basis. See “Plan of Distribution.” Our Common Shares trade on the Nasdaq Global Market under the symbol “NB.” On September 25, 2025, the last reported saleprice of our Common Shares on the Nasdaq Global Market was $7.31 per Common Share. There is no established trading market forthe Pre-Funded Warrants and we do not expect a market to develop. In addition, we do not intend to list the Pre-Funded Warrants onany national securities exchange or any other nationally recognized trading system. Investing in our securities involves a high degree of risk. See “Risk Factors” beginning on page S-4 of this prospectussupplement and on page 2 of the accompanying prospectus, and the documents incorporated by reference herein and therein. Neither the Securities and Exchange Commission (the “SEC”) nor any state securities commission has approved ordisapproved of these securities or determined if this prospectus supplement or the accompanying prospectus is truthful orcomplete. Any representation to the contrary is a criminal offense. We have engaged Maxim Group LLC (the “Placement Agent”) to act as our exclusive placement agent in connection with thisoffering. The Placement Agent has agreed to use its reasonable best efforts to solicit offers for the securities offered by this prospectussupplement and accompanying prospectus. The Placement Agent does not have any obligation to sell any specific number or dollaramount of the securities being offered hereby, nor are we requiring any minimum purchase or sale of any specific number of securitiesin order for us to consummate this offering and there are no arrangements to place the funds in an escrow, trust, or similar account. ThePlacement Agent is not purchasing or selling any of the securities we are offering. We have agreed to pay the Placement Agent thecommissions set forth in the table below. See “Plan of Distribution” beginning on page S-24 of this prospectus supplement for moreinformation regarding these arrangements. (1)We have agreed to pay the Placement Agent a cash placement commission equal to 7.00% of the aggregate proceeds from the saleof the Common Shares and the Pre-Funded Warrants sold in this offering to the investors. The Company has agreed to reimbursethe Placement Agent for certain expenses incurred in connection with this offering. See “Plan of Distribution” for additionaldisclosure regarding the Placement Agent’s compensation. (2)Reflects actual amounts. The securities are expected to be delivered on or about September 29, 2025, subject to satisfaction of customary closingconditions. Sole Placement Agent Maxim Group LLC The date of this prospectus supplement is September 26, 2025. TABLE OF CONTENTS Prospectus Supplement About This Prospectus SupplementWhere You Can Find More InformationIncorporation of Documents By ReferenceProspectus Supplement SummaryRisk FactorsCautionary Note Regarding Forward-Looking StatementsUse of ProceedsDilutionDescription of SecuritiesCertain United States Federal Income Tax ConsiderationsCertain Canadian Federal Income Tax Considerations For U.S. ResidentsPlan of DistributionLegal MattersExperts Prospectus About This ProspectusWhere You Can Find More InformationInformation Incorporated by ReferenceSummaryRisk FactorsCautionary Note Regarding Forward-Looking StatementsUse of ProceedsDescription of Capital StockDescription of WarrantsDescription of UnitsPlan of DistributionLegal MattersExperts ABOUT THIS PROSPECTUS SUPPLEMENT On June 13, 2024, we filed with the SEC a registration statement on Form S-3. The registration statement was declared effectiveon June 27, 2024. This prospectus supplement describes the specific terms of the securities we are offering and adds to, and updates, information inthe accompanying prospectus and the documents incorporated by reference herein and therein. If there is a conflict between theinformation contained in this prospectus supplement and the information contained in the accompanying prospectus or any documentincorporated by reference into it or into this prospectus s