NioCorp Developments Ltd美股招股说明书(2025-07-17版)

Preliminary Prospectus Supplement, dated July 16, 2025 offering, minus $0.0001, which is the exercise price of each Pre-Funded Warrant. The Pre-Funded Warrants will not have an expirationdate and will be immediately exercisable. The public offering price for each Common Share is $ relates to the offering of Common Shares issuable upon exercise of the Pre-Funded Warrants. The Common Shares and Pre-Funded Our Common Shares trade on the Nasdaq Global Market under the symbol “NB.” On July 16, 2025, the last reported sale price ofour Common Shares on the Nasdaq Global Market was $3.99 per Common Share. There is no established trading market for the Pre-Funded Warrants and we do not expect a market to develop. In addition, we do not intend to list the Pre-Funded Warrants on anynational securities exchange or any other nationally recognized trading system. disapproved 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 this amount 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 the information regarding these arrangements. Placement Agent fees(1)$$$Proceeds, before expenses, to us$$$(1)We have agreed to pay the Placement Agent a cash placement commission equal to 7.00% of the aggregate proceeds from the sale S-iii 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 supplement that was filed with the SEC before the date of this prospectus prospectus supplement—the statement in the document having the later date modifies or supersedes the earlier statement.Documents incorporated by reference herein include industry and market data and other information that we have obtained from, other information is subject to change based on various factors, including those described in this prospectus supplement and theaccompanying prospectus under the heading “Risk Factors” and under Item 1A. “Risk Factors” in our most recent Annual Report onForm 10-K filed with the SEC, which is incorporated herein by reference.We have not authorized anyone to provide you with different information from the information contained or incorporated by incorporated by reference, or any free writing prospectus is accurate as of any date, other than the date mentioned on the cover page ofthese documents. We are not making offers to sell the securities in any jurisdiction in which an offer or solicitation is not authorized or in which the person making such offer or solicitation is not qualified to do so or to anyone to whom it is unlawful to make an offer orsolicitation.Unless we state otherwise or the context otherwise requires, the terms “we,” “us,” “our,” “our business,” “NioCorp,” “theCompany” and similar references refer to NioCorp Developments Ltd. and its consolidated subsidiaries. WHERE YOU CAN FIND MORE INFORMATIONThis prospectus supplement and the accompanying prospectus are part of a registration statement on Form S-3 that we filed withthe SEC under the Securities Act of 1933, as amended (the “Securities Act”), and does not contain all the information set forth or incorporated by reference in the registration statement. Whenever a reference is made in this prospectus supplement and theaccompanying prospectus to any of our contracts, agreements or other documents, the reference may not be complete and you shouldrefer to the exhibits that are a part of the registration statement of which this prospectus supplement and the accompanying prospectusare a part or the exhibits to the reports or other documents incorporated by reference into this prospectus supplement and theaccompanying prospectus for a copy of such contract, agreement or other document. You may obtain copies of the registration with the SEC at www.sec.gov.We make available, free of charge, on our website at www.niocorp.com, our annual reports on Form 10-K, quarterly reports on practicable after they are filed with the SEC. We do not incorporate the information on or accessible through any website into thisprospectus supplement or the accompanying prospectus, and you should not consider any information on, or that