Mr. Jim Sims reports

NIOCORP ANNOUNCES DELAY IN FILING ANNUAL FINANCIAL STATEMENTS

Niocorp Developments Ltd. anticipates a delay in filing its annual financial statements for the year ended June 30, 2023, the related management discussion and analysis, and the chief executive officer and chief financial officer certifications relating to the annual financial statements, before the Sept. 28, 2023, deadline.

The closing of the Company's previously announced business combination (the "Business Combination") with GX Acquisition Corp. II ("GX"), and the ongoing complexities in integrating GX and accounting for the Business Combination has resulted in the anticipated delay in filing the Required Documents.

The Company has applied to the Ontario Securities Commission (the "OSC"), as principal Canadian regulator for the Company, for the imposition of a management cease trade order ("MCTO") under National Policy 12-203 - Management Cease Trade Orders ("NP 12-203") throughout the duration of the default. The MCTO, if approved, would generally not affect the ability of persons who are not management of the Company to trade in its securities. While no assurance can be given that the MCTO will be issued, the Company's existing Insider Trading Policy prohibits any and all trading by Company employees until at least three days following the filing of the Required Documents.

The OSC may issue a general cease trade order against the Company for failure to file the Required Documents within the prescribed time period or sooner if the Company fails to file its status reports during the prescribed time limits.

The Company confirms that it will satisfy the provisions of the alternative information guidelines under NP 12-203 by issuing bi-weekly default status reports in the form of news releases for so long as it remains in default of the above-noted filing requirements and further confirms there is no other material information relating to its affairs that has not been generally disclosed.

NioCorp's management is working diligently to remedy the situation and anticipates the Required Documents will be filed as soon as they are available, likely by October 6, 2023. As a U.S. Securities and Exchange Commission (the "SEC") reporting issuer, NioCorp anticipates filing a Form 12b-25 Notice of Late Filing (the "12b-25 Notice") with the SEC on or before September 29, 2023, to provide for an extension to file its Annual Report on Form 10-K through October 13, 2023.

NioCorp intends to provide updates on further developments in respect of this matter promptly following their occurrence.

Other than as disclosed herein, the Company is up to date in its filing obligations.# # #

About NioCorp

NioCorp is developing a critical minerals project in Southeast Nebraska that is expected to produce niobium, scandium, and titanium, subject to the receipt of sufficient project financing. The Company also is evaluating the potential to produce several rare earths from the Elk Creek Project. Niobium is used to produce specialty alloys as well as High Strength, Low Alloy steel, which is a lighter, stronger steel used in automotive, structural, and pipeline applications. Scandium is a specialty metal that can be combined with Aluminum to make alloys with increased strength and improved corrosion resistance. Scandium is also a critical component of advanced solid oxide fuel cells. Titanium is used in various lightweight alloys and is a key component of pigments used in paper, paint and plastics and is also used for aerospace applications, armor, and medical implants. Magnetic rare earths, such as neodymium, praseodymium, terbium, and dysprosium are critical to the making of Neodymium-Iron-Boron magnets, which are used across a wide variety of defense and civilian applications.

We seek Safe Harbor.