Exhibit
10.2


EXECUTION
AGREEMENT


COMPANY
SUPPORT AGREEMENT


This
Company Support Agreement (this “Agreement”) is dated as of September 25, 2022, by and among GX Acquisition Corp.
II, a Delaware corporation (“GX”), NioCorp Developments Ltd., a company incorporated under the laws of the Province
of British Columbia (the “Company”), and the shareholders of the Company set forth on Schedule I hereto (the
“Company Shareholders”). Capitalized terms used but not otherwise defined herein shall have the respective meanings
ascribed to such terms in the Business Combination Agreement.


RECITALS


WHEREAS,
as of the date hereof, each Company Shareholder is a “beneficial owner” (within the meaning of Rule 13d-3 under the Securities
Exchange Act of 1934, as amended (the “Exchange Act”)) of the common shares in the capital of the Company identified
on Schedule I attached hereto as being beneficially owned by such Company Shareholder (such shares, the “Company Shares”);


WHEREAS,
contemporaneously with the execution and delivery of this Agreement, GX, the Company and Big Red Merger Sub Ltd, a Delaware corporation
and a direct, wholly owned subsidiary of the Company (“Merger Sub”), entered into a Business Combination Agreement
(as amended or modified from time to time, the “Business Combination Agreement”) pursuant to which, among other transactions,
(i) Merger Sub will merge with and into GX, with GX surviving the merger, (ii) the Company will purchase all shares of Class A common
stock of GX as the surviving corporation of such merger (other than the shares of Class A common stock then held by the Company) in exchange
for Company Common Shares, (iii) all shares of GX Class A common stock will be transferred by the Company to 0896800 B.C. Ltd., a company
organized under the laws of the Province of British Columbia and a direct wholly owned subsidiary of the Company (“Intermediate
Holdco”) in exchange for additional shares of Intermediate Holdco, and (iv) Elk Creek Resources Corporation, a Nebraska corporation
and a direct wholly owned subsidiary of Intermediate Holdco, will merge with and into GX, with GX surviving (collectively, and together
with the other transactions contemplated by the Business Combination Agreement and the Ancillary Agreements, the “Transactions”);


WHEREAS,
Mark A. Smith (“Smith”), as lender, and the Company, as borrower, have entered into a credit facility agreement dated
January 16, 2017, providing for a non-revolving credit facility in the amount of up to $3,500,000 expiring on June 30, 2023 (as amended,
the “Smith Credit Agreement”);


WHEREAS,
Smith and the Company have entered into a general security agreement dated June 17, 2015 securing, among others, the obligations of the
Company under the Smith Credit Agreement (the “Smith GSA”);


WHEREAS,
in connection with the execution by the Company of the Business Combination Agreement, the Company has asked that Smith (i) waive certain
Events of Default (as defined in the Smith Credit Agreement) and/or “defaults” (as defined in the Smith GSA) which have occurred
or may occur, in each case, in connection with the Transactions, (ii) waive such other applicable rights (to acceleration or otherwise)
under the Smith Credit Agreement and the



    	 	 	 



    	 



    







Smith
GSA, in each case, with respect to the Transactions, and (iii) provide its consent and approval, if required, in connection with the
Transactions and the entering into by the Company of the Business Combination Agreement and each of the applicable Ancillary Agreements;
and


WHEREAS,
as an inducement to GX and the Company to enter into the Business Combination Agreement and to consummate the Transactions, the parties
hereto desire to agree to certain matters as set forth herein.


AGREEMENT


NOW,
THEREFORE, in consideration of the foregoing and the mutual agreements contained herein, and intending to be legally bound hereby, the
parties hereto agree as follows:


ARTICLE
I

SUPPORT AGREEMENT; COVENANTS


Section
1.1            No Transfer. During the period commencing on the date hereof
and ending on the earliest of (a) the Second Merger Effective Time, (b) such date and time as the Business Combination Agreement has
been terminated in accordance with its terms (the earlier of (a) and (b), the “Support Expiration Time”) and (c) the
liquidation of GX, each Company Shareholder shall not (i) sell, offer to sell, contract or agree to sell, hypothecate, pledge, grant
any option to purchase or otherwise dispose of or agree to dispose of (each, a “Transfer”), directly or indirectly,
file (or participate in the filing of) a registration statement with the SEC (other than the Joint Proxy Statement and Form S-4) or establish
or increase a put equivalent position or liquidate or decrease a call equivalent position within the meaning of Section 16 of the Exchange
Act, with respect to any Company Shares owned by such Company Shareholder, (ii) enter into any swap or other arrangement that transfers
to another, in whole or in part, any of the economic consequences of ownership of any shares of Company Shares owned by such Company
Shareholder, or grant or enter into any proxy (except in accordance with this Agreement), voting trust or other agreement or arrangement
with respect to the voting of any Company Shares owned by such Company Shareholder, or (iii) publicly announce any intention to effect
any transaction specified in clause (i) or (ii); provided, however, that the foregoing restrictions will not apply to (A)
a Company Shareholder’s transfer to an officer or director of the Company or any affiliate or family member of any of the Company’s
officers or directors; (B) a Company Shareholder’s transfer to a member of such Company Shareholder’s immediate family, a
trust, the beneficiary of which is a member of such Company Shareholder’s immediate family, an affiliate of such Company Shareholder
or a charitable organization; (C) a transfer by virtue of laws of descent and distribution upon death of such Company Shareholder; (D)
a transfer pursuant to a qualified domestic relations order; or (E) a transfer to satisfy tax withholding obligations in connection with
the exercise of rights to purchase Company Shares or the vesting of stock-based awards, including without limitation, sell-to-cover transactions
(each, a “Permitted Transfer”); provided, however, that, prior to and as a condition to the effectiveness
of any Permitted Transfer, the transferee shall have executed and delivered to GX a joinder or counterpart of this Agreement pursuant
to which such transferee shall be bound by all of the applicable terms and provisions of this Agreement. Any Transfer of any Company
Shares in violation of any provision of this Agreement shall be void ab initio and of no force or effect.






    	 	2	 



    	 



    

 


Section
1.2            New Shares. In the event that (a) any Company Shares or
other equity securities of the Company are issued to a Company Shareholder after the date of this Agreement pursuant to any stock dividend,
stock split, recapitalization, reclassification, combination, exchange of shares or other similar event of Company Shares of, on or affecting
the Company Shares owned by such Company Shareholder or otherwise, (b) a Company Shareholder purchases or otherwise acquires beneficial
ownership of any Company Shares or other equity securities of the Company after the date of this Agreement (including without limitation
upon the exercise or settlement of options or other equity-based awards), or (c) a Company Shareholder purchases or otherwise acquires
the right to vote or share in the voting of any Company Shares or other equity securities of the Company after the date of this Agreement
(such Company Shares or other equity securities of the Company, collectively the “New Securities”), then such New
Securities acquired or purchased by, or otherwise issued to, such Company Shareholder shall be subject to the terms of this Agreement
to the same extent as if they constituted the Company Shares owned by such Company Shareholder as of the date hereof.


Section
1.3            Closing Date Deliverables. On the Closing Date, the Company
Shareholders shall deliver to GX and the Company a duly executed copy of the Registration Rights and Lock-Up Agreement.


Section
1.4            Company Shareholder Agreements. At any meeting of the shareholders
of the Company, however called, or at any adjournment thereof, or in any other circumstance in which the vote, consent or other approval
of the shareholders of the Company is sought, each Company Shareholder shall (i) appear at each such meeting or otherwise cause all of
his or her Company Shares to be counted as present thereat for purposes of calculating a quorum and (ii) vote (or cause to be voted),
or execute and deliver a written consent (or cause a written consent to be executed and delivered) covering, all of his or her Company
Shares:


		(a)	in
                                            favor of each Company Resolution and any other matter necessary for the consummation of the
                                            Transactions;
	 	 	 
	 	(b)	against
                                            any (i) merger agreement, merger, amalgamation, arrangement or other Acquisition Proposal
                                            (in each case, other than the Business Combination Agreement and the Transactions) or (ii)
                                            consolidation, combination, sale of substantial assets, reorganization, recapitalization,
                                            dissolution, liquidation or winding up of or by the Company;




		(c)	against
                                            any change in the business, management or board of directors of the Company (other than in
                                            connection with the Company Resolutions); and



		(d)	against
                                            any proposal, action or agreement that would (i) impede, frustrate, prevent or nullify any
                                            provision of this Agreement, the Business Combination Agreement or the Transactions, (ii)
                                            result in a breach of any covenant, representation, warranty or any other obligation or agreement
                                            of the Company under the Business Combination Agreement, (iii) result in any of the conditions
                                            set forth in Article VI of the Business Combination Agreement not being fulfilled, or (iv)
                                            change in any manner the dividend





    	 	3	 



    	 



    




			policy
                                            or capitalization of, including the voting rights of any class of shares of, the Company
                                            (other than in connection with the Company Resolutions).





Section
1.5            Further Assurances. Each Company Shareholder shall take,
or cause to be taken, all actions and do, or cause to be done, all things reasonably necessary under applicable Laws to consummate the
Transactions on the terms and subject to the conditions set forth therein and herein. Without limiting the foregoing, no later than five
Business Days prior to any meeting of the shareholders of the Company, each Company Shareholder shall deliver or cause to be delivered
to the Company duly executed proxies or voting instruction forms voted in accordance with the terms hereof, such proxy or voting instruction
forms not to be revoked or withdrawn without the prior written consent of GX. Prior to a Company Recommendation
Change, no Company Shareholder will communicate with any shareholder of the Company in a manner inconsistent with the Company Board recommendation
in favor of the Transactions and the Business Combination Agreement.


Section
1.6            No Inconsistent Agreement. Each Company Shareholder represents
and covenants that such Company Shareholder has not entered into, and shall not enter into, any agreement, or amend or modify any existing
agreement, that would restrict, limit or interfere with the performance of such Company Shareholder’s obligations hereunder.


Section
1.7            Binding Effect of Business Combination Agreement. Each Company
Shareholder shall be bound by and comply with Section 5.2 and Section 5.8 of the Business Combination Agreement as if (a) such Company
Shareholder was an original signatory to the Business Combination Agreement with respect to such provision and (b) each reference to
“the Company” in Section 5.2 and Section 5.8 of the Business Combination Agreement also referred to each Company Shareholder.
Nothing in this Agreement is intended to restrict a Company Shareholder’s discretion to act (including, for the avoidance of doubt,
Smith), when acting in his or her capacity as an officer or director of the Company, in a manner consistent with all fiduciary obligations
imposed on such Company Shareholder in that capacity, subject to and in accordance with the Business Combination Agreement. For greater
certainty, the obligations of a Company Shareholder hereunder to vote in favor of the Company Resolutions and not take any actions inconsistent
with that support are intended to apply to such Company Shareholder only in his or her capacity as a holder of securities of the Company
and not in such Company Shareholder’s capacity as an officer or director of the Company, and any such actions taken by a Company
Shareholder in such capacity shall not constitute a breach or violation of this Agreement.


Section
1.8            Tax Treatment. Each party hereto agrees to report the Transactions
in all cases in accordance with the Intended Tax Treatment except, and then solely to the extent, otherwise required by a final determination
under applicable Law.


ARTICLE
II

REPRESENTATIONS AND WARRANTIES


Section
2.1            Representations and Warranties of the Company Shareholders.
Each Company Shareholder represents and warrants as of the date hereof to GX and the Company




    	 	4	 



    	 



    

(solely
with respect to himself or herself and not with respect to any other Company Shareholder) as follows:


(a)         
Organization; Due Authorization. Such Company Shareholder has full legal capacity, right and authority to execute and deliver
this Agreement and to perform his or her obligations hereunder. This Agreement has been duly executed and delivered by such Company Shareholder
and, assuming due authorization, execution and delivery by the other parties to this Agreement, this Agreement constitutes a legally
valid and binding obligation of such Company Shareholder, enforceable against such Company Shareholder in accordance with the terms hereof
(subject to the Enforceability Exceptions). If this Agreement is being executed in a representative or fiduciary capacity, the Person
signing this Agreement has full power and authority to enter into this Agreement on behalf of the applicable Company Shareholder.


(b)         
Ownership. Such Company Shareholder is the beneficial owner (as defined in the Securities Act) of, and has good title to, all
of such Company Shareholder’s Company Shares, and there exist no Liens or any other limitation or restriction (including any restriction
on the right to vote, sell or otherwise dispose of such Company Shares (other than transfer restrictions under the Securities Act)) or
preemptive or other right or privilege for the purchase, acquisition or transfer from such Company Shareholder affecting any such Company
Shares, other than Liens pursuant to (i) this Agreement, (ii) the organizational documents of the Company, (iii) the Business Combination
Agreement, or (iv) any applicable securities Laws. As of the date of this Agreement, such Company Shareholder’s Company Shares
are the only equity securities in the Company owned beneficially by such Company Shareholder or over which such Company Shareholder has
voting control or direction, and none of such Company Shareholder’s Company Shares are subject to any proxy, voting trust or other
agreement or arrangement with respect to the voting of such Company Shares. Other than any options to purchase Company Shares, such Company
Shareholder does not hold or own any rights to acquire (directly or indirectly) any equity securities of the Company or any equity securities
convertible into, or which can be exchanged for, equity securities of the Company.


(c)              
No Conflicts. The execution and delivery of this Agreement by such Company Shareholder does not, and the performance by such Company
Shareholder of his or her obligations hereunder will not require any consent or approval that has not been given or other action that
has not been taken by any Person (including under any contract binding upon such Company Shareholder or such Company Shareholder’s
Company Shares), in each case, to the extent such consent, approval or other action would prevent, enjoin or materially delay the performance
by such Company Shareholder of his or her obligations under this Agreement.


(d)              
Litigation. There are no Actions pending against such Company Shareholder, or to the knowledge of such Company Shareholder threatened
against such Company Shareholder, before (or, in the case of threatened Actions, that would be before) any arbitrator or any Governmental
Entity, which in any manner challenges or seeks to prevent, enjoin or materially delay the performance by such Company Shareholder of
his or her obligations under this Agreement.


(e)              
Brokerage Fees. Except as set forth on Section 3.24 of the Company Disclosure Letter, no broker, finder, investment banker or
other Person is entitled to any brokerage




    	 	5	 



    	 



    

fee,
finders’ fee or other commission in connection with the Transactions upon arrangements made by such Company Shareholder, for which
the Company or any of its Affiliates may become liable.


(f)               
Acknowledgment. Such Company Shareholder understands and acknowledges that each of GX and the Company is entering into the Business
Combination Agreement in reliance upon such Company Shareholder’s execution and delivery of this Agreement.


(g)              
Disclosure. Each of the undersigned hereby consents to the disclosure of this Agreement and the terms and conditions hereof in
any press release or other documents filed pursuant to applicable securities laws in connection with the Business Combination Agreement
or the Transactions.


ARTICLE
III

Consent and Waiver


Section
3.1            Consent and Waiver(a). Smith hereby consents to and confirms
that (in each case, to the extent required pursuant to the Smith Credit Agreement or the Smith GSA):


(a)              
The Company shall be permitted to enter into the Business Combination Agreement and each of the Ancillary Agreements to which it is a
party, to consummate the Transactions and any Contemplated Financing;


(b)         
The Company shall be permitted to do, or cause to be done, all such acts and things as may be deemed necessary or desirable by the Company
in order to implement the Transactions, enter into definitive documentation with respect to, and consummate, any Contemplated Financing;
and


(c)              
Any Event of Default (as defined in the Smith Credit Agreement) or “default” (as defined in the GSA), applicable right to
acceleration, or breach or event of noncompliance which have occurred or may occur, in each case, in connection with the Transactions
and any Contemplated Financing, is hereby waived.


(d)              
The waiver and consent hereby granted shall be effective only with respect to the matters referred to above and not with respect to any
other events, facts or circumstances, and Smith shall be entitled to assert and exercise in good faith all rights and powers granted
to him under the Smith Credit Agreement and Smith GSA in respect of any such other events, facts or circumstances.


ARTICLE
IV

MISCELLANEOUS


Section
4.1            Termination. This Agreement and all of its provisions shall
terminate and be of no further force or effect upon the earliest of (a) the Support Expiration Time and (b) the written agreement of
the Company Shareholders, GX and the Company. Upon a termination of this Agreement all obligations of the parties under this Agreement
or such provisions, as applicable, will terminate, without any liability or other obligation on the part of any




    	 	6	 



    	 



    

party
hereto to any Person in respect hereof or the transactions contemplated hereby, and no party hereto shall have any claim against another
(and no Person shall have any rights against such party), whether under contract, tort or otherwise, with respect to the subject matter
hereof; provided, however, that the termination of this Agreement or any provision hereof shall not relieve any party hereto
from liability arising in respect of any breach of this Agreement prior to such termination. This ARTICLE IV shall survive the
termination of this Agreement.


Section
4.2            Governing Law; Venue; Waiver of Jury Trial.


(a)         
This Agreement will be construed and enforced in accordance with the Laws of the State of Delaware, without regard to the conflict of
laws principles that would result in the application of any Law other than the Law of the State of Delaware.


(b)         
Each of the parties hereby irrevocably and unconditionally submits, for itself and its property, to the exclusive jurisdiction and venue
of the Court of Chancery of the State of Delaware (or, to the extent that such Court does not have subject matter jurisdiction, the Superior
Court of the State of Delaware) or, if it has or can acquire jurisdiction, in the United States District Court for the District of Delaware
(collectively, the “Chosen Courts”), in any proceeding arising out of or relating to this Agreement or the agreements
delivered in connection herewith or the Transactions or for recognition or enforcement of any judgment relating thereto, and each of
the parties hereby irrevocably and unconditionally (i) agrees not to commence any such proceeding, except in the Chosen Courts;
(ii) agrees that any claim in respect of any such proceeding may be heard and determined in the Chosen Courts; (iii) waives,
to the fullest extent it may legally and effectively do so, any objection that it may now or hereafter have to the laying of venue of
any such proceeding in the Chosen Courts; and (iv) waives, to the fullest extent permitted by Law, the defense of an inconvenient
forum to the maintenance of such proceeding in the Chosen Courts. Each of the parties agrees that a final judgment in any such proceeding
shall be conclusive and may be enforced in other jurisdictions by suit on the judgment or in any other manner provided by applicable
Law. Each party irrevocably consents to service of process inside or outside the territorial jurisdiction of the Chosen Courts the manner
provided for notices in Section 4.7. Nothing in this Agreement will affect the right of any party to this Agreement to serve
process in any other manner permitted by applicable Law.


(c)         
EACH PARTY HEREBY IRREVOCABLY WAIVES, AND WILL CAUSE ITS SUBSIDIARIES AND AFFILIATES TO WAIVE, ANY AND ALL RIGHTS TO TRIAL BY JURY IN
ANY LEGAL PROCEEDING ARISING OUT OF OR RELATED TO THIS AGREEMENT OR THE TRANSACTIONS.


Section
4.3            Assignment. This Agreement will be binding upon and inure
to the benefit of the parties and their respective successors, legal representatives and permitted assigns. No party may assign any of
its rights or delegate any of its obligations under this Agreement, by operation of Law or otherwise, without the prior written consent
of the other Party.


Section
4.4            Specific Performance. The parties agree that irreparable
damage for which monetary damages, even if available, would not be an adequate remedy, would occur in the event that the parties do not
perform their obligations under the provisions of this Agreement (including failing to take such actions as are required of them hereunder
to consummate this




    	 	7	 



    	 



    

Agreement)
in accordance with its specified terms or otherwise breach such provisions. Subject to the other provisions of this Section 4.4,
the parties acknowledge and agree (and further agree not to take any contrary position in any litigation concerning this Agreement) that
(a) the parties will be entitled to an injunction or injunctions, specific performance, or other equitable relief, to prevent breaches
of this Agreement and to enforce specifically the terms and provisions hereof without proof of damages or otherwise, and that such relief
may be sought in addition to and will not limit, diminish or otherwise impair, any other remedy to which they are entitled under this
Agreement, (b) the provisions set forth herein are not intended to and do not adequately compensate for the harm that would result
from a breach of this Agreement and will not be construed to limit, diminish or otherwise impair in any respect any party’s right
to specific enforcement, and (c) the right of specific enforcement is an integral part of the Transactions and without that right,
none of the parties would have entered into this Agreement. The parties acknowledge and agree that any party seeking an injunction or
injunctions to prevent breaches of this Agreement and to enforce specifically the terms and provisions of this Agreement in accordance
with this Section 4.4 will not be required to provide any bond or other security in connection with any such order or injunction.


Section
4.5            Amendment. This Agreement may not be amended, changed, supplemented,
waived or otherwise modified or terminated, except upon the execution and delivery of a written agreement executed by GX, the Company
and the Company Shareholders.


Section
4.6            Severability. The provisions of this Agreement will be deemed
severable and the invalidity or unenforceability of any provision will not affect the validity or enforceability of the other provisions
hereof. If any provision of this Agreement, or the application thereof to any Person or any circumstance, is invalid or unenforceable,
then (a) a suitable and equitable provision will be substituted therefor in order to carry out, so far as may be valid and enforceable,
the intent and purpose of such invalid or unenforceable provision and (b) the remainder of this Agreement and the application of
such provision to other Persons or circumstances will not be affected by such invalidity or unenforceability, nor will such invalidity
or unenforceability affect the validity or enforceability of such provision, or the application thereof, in any other jurisdiction.


Section
4.7            Notices. All notices and other communications among the
parties will be in writing and will be deemed to have been duly given (a) when delivered in person, (b) when delivered by FedEx
or other nationally recognized overnight delivery service, or (c) when delivered by email (so long as the sender of any such e-mail
has not received an e-mail from the applicable server indicating a delivery failure), in each case, according to the instructions set
forth below. Such notices will be deemed given: at the time of personal delivery, if delivered in person; one (1) Business Day after
being sent, if sent by reputable, overnight delivery service and at the time sent (so long as the sender of any such e-mail has not received
an e-mail from the applicable server indicating a delivery failure), if sent by email prior to 5:00 p.m. local time of the recipient
on a Business Day; or on the next Business Day if sent by email after 5:00 p.m. local time of the recipient on a Business Day or on a
non-Business Day.


If
to GX:


GX
Acquisition Corp. II




    	 	8	 



    	 



    

1325
Avenue of the Americas, 28th Floor


New
York, New York 10019


	 	Attention:
	Jay Bloom
	 	 	Dean
Kehler
	 	Email:	jay.bloom@trimarancapital.com
	 	 	dean.kehler@trimarancapital.com









 


with
a copy to (which will not constitute notice):


 


Skadden, Arps, Slate, Meagher & Flom LLP

One Manhattan West

New York, New York 10001


	 	Attention:	Michael Chitwood
	 	 	Michael Civale
	 	Email:	Michael.Chitwood@skadden.com
	 	 	Michael.Civale@skadden.com



 


If
to a Company Shareholder:


 


To
such Company Shareholder’s address set forth in Schedule I


with
a copy to (which will not constitute notice):


Jones
Day


250
Vesey Street


New
York, NY 10281


	 	Attention:
	Joel May
	 	 	Ann
Bomberger
	 	Email:
	jtmay@jonesday.com
	 	 	ambomberger@jonesday.com






                 


If
to the Company:


NioCorp
Developments Ltd.


7000
South Yosemite Street, Suite 115


Centennial,
CO 80112


	 	Attention:
	Mark Smith
	 	 	
Neal Shah
	 	Email:
	msmith@niocorp.com
	 	 	nshah@niocorp.com









 


with
copies to (which shall not constitute notice):


 


Jones
Day


250
Vesey Street


New
York, NY 10281


	 	Attention:
	Joel May
	 	 	Ann
Bomberger









                    




    	 	9	 



    	 



    




	 	Email:
	jtmay@jonesday.com
	 	 	ambomberger@jonesday.com



 


and
to


 


Blake,
Cassels & Graydon LLP

2600 – 595 Burrard Street

Vancouver, BC V7X 1L3

Attention:Bob Wooder

E-mail:bob.wooder@blakes.com


 


Section
4.8            Counterparts. This Agreement may be executed in any number
of counterparts (including by pdf or other readable electronic format), each such counterpart being deemed to be an original instrument,
with the same effect as if the signature thereto and hereto were upon the same instrument, and will become effective when one or more
counterparts have been signed by each of the parties and delivered (including by email or DocuSign) to the other parties, and all such
counterparts will together constitute one and the same agreement.


Section
4.9            Entire Agreement. This Agreement and the agreements referenced
herein constitute the entire agreement, and supersede all other prior agreements, understandings, representations and warranties both
written and oral, among the parties, with respect to the subject matter hereof.


Section
4.10        No Third-Party Beneficiaries. The representations, warranties and covenants set
forth herein are solely for the benefit of the other parties, in accordance with and subject to the terms of this Agreement, and this
Agreement is not intended to, and does not, confer upon any Person other than the parties hereto any rights or remedies hereunder, including
the right to rely upon the representations and warranties set forth herein; provided that GX Sponsor II LLC is an intended third-party
beneficiary of, and may enforce, GX’s rights under this Agreement.


[THE
REMAINDER OF THIS PAGE IS INTENTIONALLY BLANK]




    	 	10	 



    	 



    

IN
WITNESS WHEREOF, the Company Shareholders, GX and the Company have each caused this Agreement to be duly executed as of the date first
written above.





 


	 	COMPANY
    SHAREHOLDERS:
	 	 
	 	/s/
    Mark A. Smith
	 	Name: Mark
    A. Smith
	 	 
	 	 
	 	/s/
    Neal Shah
	 	Name: Neal
    Shah
	 	 
	 	 
	 	/s/
    Scott Honan
	 	Name:Scott
    Honan
	 	 
	 	 
	 	/s/
    Jim Sims
	 	Name:Jim
    Sims
	 	 
	 	 
	 	/s/
    Michael Morris
	 	Name:Michael
    Morris
	 	 
	 	 
	 	/s/
    David Beling
	 	Name:David
    Beling
	 	 
	 	 
	 	/s/
    Anna Castner Wightman
	 	Name:Anna
    Castner Wightman
	 	 	 	 
	 	 	 	 





 




    		[Signature Page to Company Support Agreement]	 



    	 



    

 





	 	GX:
	 	 
	 	 
	 	GX ACQUISITION
    CORP. II
	 	 
	 	 
	 	By:  	/s/
    Dean Kehler
	 	 	Name:  Dean Kehler  
	 	 	Title:    Co-Chairman and Chief Executive Officer  
	 	 	 	 





 


 




    		[Signature Page to Company Support Agreement]	 



    	 



    

 





		COMPANY:
	 	 
	 	NIOCORP DEVELOPMENTS
    LTD.
	 	 
	 	 
	 	By:  	/s/
    Mark Smith
	 	 	Name:  Mark Smith  
	 	 	Title:    Chief Executive Officer  
	 	 	 	 


 


 




    		[Signature Page to Company Support Agreement]	 



    	 



    

Schedule
I


 


Company
Shares


 


	Company
    Shareholder	Company
    Shares
	Mark
                                            A. Smith

    c/o
    NioCorp Developments Ltd.

    7000
    South Yosemite Street, Suite 115

    Centennial,
    CO 80112
	19,565,395
	Neal
                                            Shah

    c/o
    NioCorp Developments Ltd.

    7000
    South Yosemite Street, Suite 115

    Centennial,
    CO 80112
	401,000
	Scott
                                            Honan

    c/o
    NioCorp Developments Ltd.

    7000
    South Yosemite Street, Suite 115

    Centennial,
    CO 80112
	365,042
	Jim
                                            Sims

    c/o
    NioCorp Developments Ltd.

    7000
    South Yosemite Street, Suite 115

    Centennial,
    CO 80112
	390,826
	Michael
                                            Morris

    c/o
    NioCorp Developments Ltd.

    7000
    South Yosemite Street, Suite 115

    Centennial,
    CO 80112
	310,876
	David
                                            Beling

    c/o
    NioCorp Developments Ltd.

    7000
    South Yosemite Street, Suite 115

    Centennial,
    CO 80112
	589,255
	Anna
                                            Castner Wightman

    c/o
    NioCorp Developments Ltd.

    7000
    South Yosemite Street, Suite 115

    Centennial,
    CO 80112
	295,620


 






    		[Schedule I to Company Support Agreement]