Document:

Exhibit 4.4

THE WARRANTS EVIDENCED HEREBY ARE
EXERCISABLE AT OR BEFORE 4:30 P.M. (VANCOUVER TIME) ON MAY 10, 2023 AFTER WHICH TIME THE WARRANTS EVIDENCED HEREBY SHALL BE DEEMED TO
BE VOID AND OF NO FURTHER FORCE OR EFFECT.

UNLESS PERMITTED UNDER SECURITIES LEGISLATION,
THE HOLDER OF THIS SECURITY MUST NOT TRADE THE SECURITY BEFORE SEPTEMBER 11, 2021.

THE SECURITIES REPRESENTED HEREBY AND THE
SECURITIES ISSUABLE UPON EXERCISE HEREOF HAVE NOT BEEN AND WILL NOT BE REGISTERED UNDER THE UNITED STATES SECURITIES ACT OF 1933, AS AMENDED
(THE “U.S. SECURITIES ACT”), OR UNDER ANY STATE SECURITIES LAWS. THE HOLDER HEREOF, BY PURCHASING THESE SECURITIES, AGREES
FOR THE BENEFIT OF NIOCORP DEVELOPMENTS LTD. (THE “COMPANY”), THAT THESE SECURITIES MAY BE OFFERED, SOLD, PLEDGED OR OTHERWISE
TRANSFERRED, DIRECTLY OR INDIRECTLY ONLY (A) TO THE COMPANY, (B) IF THE SECURITIES HAVE BEEN REGISTERED IN COMPLIANCE WITH THE REGISTRATION
REQUIREMENTS UNDER THE SECURITIES ACT AND IN ACCORDANCE WITH APPLICABLE STATE SECURITIES LAWS (C) IN COMPLIANCE WITH THE EXEMPTION FROM
THE REGISTRATION REQUIREMENTS UNDER THE SECURITIES ACT IN ACCORDANCE WITH RULE 144 THEREUNDER, IF APPLICABLE, AND IN ACCORDANCE WITH APPLICABLE
STATE SECURITIES LAWS, OR (D) IN A TRANSACTION THAT DOES NOT REQUIRE REGISTRATION UNDER THE SECURITIES ACT OR ANY APPLICABLE STATE LAWS
AND REGULATIONS GOVERNING THE OFFER AND SALE OF SECURITIES, AND, IN EACH CASE, THE HOLDER HAS, PRIOR TO SUCH SALE, FURNISHED TO THE COMPANY
AN OPINION OF COUNSEL OF RECOGNIZED STANDING, OR OTHER EVIDENCE OF EXEMPTION, REASONABLY SATISFACTORY TO THE COMPANY TO SUCH EFFECT. HEDGING
TRANSACTIONS INVOLVING THE SECURITIES ARE PROHIBITED EXCEPT IN COMPLIANCE WITH THE SECURITIES ACT. THESE SECURITIES MAY NOT CONSTITUTE
“GOOD DELIVERY” IN SETTLEMENT OF TRANSACTIONS ON CANADIAN STOCK EXCHANGES.

THIS WARRANT AND THE SECURITIES ISSUABLE
UPON EXERCISE HEREOF HAVE NOT BEEN REGISTERED UNDER THE UNITED STATES SECURITIES ACT OF 1933, AS AMENDED (THE “U.S. SECURITIES ACT”).
THIS WARRANT MAY NOT BE EXERCISED UNLESS THE SHARES ISSUABLE UPON EXERCISE OF THIS WARRANT HAVE BEEN REGISTERED UNDER THE U.S. SECURITIES
ACT AND THE APPLICABLE SECURITIES LEGISLATION OF ANY SUCH STATE OR EXEMPTIONS FROM SUCH REGISTRATION REQUIREMENTS ARE AVAILABLE.

	No. W-	**
	 	WARRANTS

WARRANT CERTIFICATE

NIOCORP
DEVELOPMENTS LTD.

7000 South Yosemite Street, Suite 115

Centennial, CO 80112

THIS CERTIFIES that, for value received:

 

(hereinafter referred to as the “Holder”)

is the registered holder of that number of
warrants (the “Warrants”) of NioCorp Developments Ltd. (the “Issuer”) set forth above.

THESE WARRANTS ARE TRANSFERABLE.

Transfer of Warrants

The Warrants and all rights hereunder are transferable
by the Holder in accordance with applicable laws by surrender of this Warrant Certificate together with a Warrant Transfer Form in the
form attached hereto as Schedule “B” at the head office of the Issuer stated above. No transfer of the Warrants shall be made
if, in the opinion of counsel to the Issuer, such transfer would result in the violation of any applicable securities laws.

    	 	 	 

    	 	-2-	 

    

Underlying Securities and Exercise Terms

Subject to adjustment as herein provided, each
Warrant entitles the Holder to purchase one common share (a “Warrant Share”) of the Issuer, as constituted on May
10, 2021 (the “Issuance Date”), at a price of $1.43 per Warrant Share until 4:30 p.m. (Vancouver Time) on May
10, 2023 (the “Expiry Date”). The Warrants and Warrant Shares are collectively referred to herein as the “Securities”.

The Issuer covenants that the Warrant Shares,
when issued upon the due exercise of the Warrants, will be fully paid and non-assessable securities of the Issuer, and will be free and
clear of all liens, charges and encumbrances. The Issuer covenants that, until the expiry of the Warrants, it will have reserved a sufficient
number of common shares to provide for the exercise of the rights represented by the Warrants.

Warrants Exercise Procedure 

The Warrants may be exercised at any time prior
to the Expiry Date of the Warrants by surrendering to the Issuer:

		(a)	this Warrant Certificate;

		(b)	the Subscription Form attached as Schedule “A” hereto, duly completed and executed; and

		(c)	a wire transfer, in accordance with the wire transfer instructions to be furnished on request, to the
Issuer in the aggregate amount of the exercise price,

at its head office stated above, or such other
office or agency of the Issuer as it may designate by notice in writing delivered to the Holder at the Holder’s address stated above.
Upon the due exercise of the Warrants, the Issuer shall issue or cause to be issued the requisite number of Warrant Shares to be issued
to the Holder pursuant to said exercise, registered in the name of the Holder or such other person as may be specified in the Subscription
Form, and each such person shall be deemed the holder of such Warrant Shares with effect from the date of such exercise. If Warrant Shares
are to be issued to a person other than the Holder, the Holder’s signature on the Subscription Form must be guaranteed by a Canadian
chartered bank, a Canadian trust company or a member firm of the Exchange. The Issuer will cause the certificates representing such Warrant
Shares to be mailed to the Holder at the Holder’s address stated above or such other address(es) as may be specified in the Subscription
Form, within five business days of the exercise of the Warrants.

Upon the due exercise of a Warrant, the Warrant
shall be deemed tendered for purposes thereof by the Holder without further notice or action by the Holder, and all rights under such
Warrant, other than the right to receive certificates representing the Warrant Shares to which the Holder is entitled on such exercise,
shall wholly cease and terminate and such Warrant shall be void and of no further effect or value.

Partial Exercise, Exchange and Replacement
of Certificates

The Warrants represented by this Warrant Certificate
may be exercised in whole or in part from time to time. If the Warrants are exercised in part, the Issuer shall deliver, with the Warrant
Shares issued pursuant to such exercise, a new Warrant Certificate representing the balance of the Warrants remaining unexercised.

This Warrant Certificate may be exchanged,
upon its surrender to the Issuer and payment of such administration fee, not exceeding $10.00, as the Issuer may require, for new Warrant
Certificates of like tenor in denominations which in the aggregate represent the number of Warrants represented hereby. Such new Warrant
Certificate will be mailed to the Holder at the Holder’s address stated above within five business days of the surrender of the
Warrant Certificate for exchange.

If this Warrant Certificate is lost, stolen,
mutilated or destroyed, the Issuer shall on such reasonable terms as it may in its discretion impose, including but not limited to the
provision of any indemnity by the Holder satisfactory to the Issuer in its sole discretion, issue and countersign a new Warrant Certificate
of like tenor, denomination and date as the Warrant Certificate so lost, stolen, mutilated or destroyed.

    	 	 	 

    	 	-3-	 

    

All Warrants shall rank pari passu,
notwithstanding the actual date of issue thereof.

Holding of Warrants

The Issuer may treat the Holder as the absolute
owner of the Warrants represented hereby for all purposes, and the Issuer shall not be affected by any notice or knowledge to the contrary
except where the Issuer is required to take notice by statute or by order of a court of competent jurisdiction.

Nothing in this Warrant Certificate or in the
holding of a Warrant evidenced hereby shall be construed as conferring upon the Holder any right or interest whatsoever as a shareholder
of the Issuer or entitle the Holder to any right or interest in respect of any Securities except as herein expressly provided.

Resale Restrictions and Legending Of
Certificates

The Warrants have been, and the Warrant Shares
will be, issued pursuant to an exemption (an “Exemption”) from the registration and prospectus requirements of applicable
securities laws. To the extent that the Issuer relies on such Exemption, the Securities may be subject to restrictions on resale and transferability
contained in applicable securities laws.

In the event that any of the Securities are
subject to a hold period, or any other restrictions on resale and transferability, the Issuer may place a legend on the certificates representing
the Securities as may be required under applicable securities laws, or as it may otherwise deem necessary or advisable.

Capital Adjustments

If at any time after the date hereof and prior
to the expiry of the Warrants, and provided that any Warrants remain unexercised, there shall be:

		(a)	a reclassification of the Issuer’s common shares, a change in the Issuer’s common shares into
other shares or securities, a subdivision or consolidation of the Issuer’s common shares into a greater or lesser number of common
shares, or any other capital reorganization, or

		(b)	a consolidation, amalgamation or merger of the Issuer with or into any other corporation other than a
consolidation, amalgamation or merger which does not result in any reclassification of the Issuer’s outstanding common shares or
a change of the Issuer’s common shares into other shares or securities,

(any of such events being called a “Capital
Reorganization”) any Holders who shall thereafter acquire Warrant Shares pursuant to the Warrants shall, subject to Exchange
approval, be entitled to receive, at no additional cost, and shall accept in lieu of the number of Warrant Shares to which such Holder
was theretofore entitled to acquire upon such exercise, the aggregate number of shares, other securities or other property which such
Holder should have been entitled to receive as a result of such Capital Reorganization if, on the effective date or record date thereof
as the case may be, the Holder had been the registered holder of the number of Warrant Shares to which such Holder was theretofore entitled
to acquire upon exercise of the Warrants. If determined appropriate by the Issuer acting reasonably, appropriate adjustments shall be
made in the application of the provisions set forth herein with respect to the rights and interests of the Holder relative to a Capital
Reorganization, to the end that the provisions set forth herein shall correspond as nearly as may be reasonably possible to the effect
of the Capital Reorganization in relation to any shares, other securities or other property thereafter deliverable upon the exercise of
any Warrants.

In case the Issuer, after the date hereof,
shall take any action affecting any securities of the Issuer, other than as previously set out herein, which in the opinion of the directors
would materially affect the rights and interests of the Holder hereunder, the number of Warrant Shares or other securities which are issuable
on the exercise of the Warrants shall be adjusted in such manner, if any, and at such time as the directors, in their sole discretion,
may determine to be equitable in the circumstances, provided that no such adjustment will be made unless all necessary regulatory and
stock exchange approvals, if any, have been obtained. In the event of any question arising with respect to any adjustment provided for
herein, such question shall be conclusively determined by a firm of chartered accountants

    	 	 	 

    	 	-4-	 

    

appointed by the Issuer at its sole discretion
(who may be the Issuer’s auditors) and any such determination shall be binding upon the Issuer and the Holder.

No adjustment shall be made in respect of any
event described herein if the Holder is entitled to participate in such event on the same terms, without amendment, as if the Holder had
exercised the Warrants prior to or on the effective date or record date of such event. The adjustments provided for herein are cumulative
and such adjustments shall be made successively whenever an event referred to herein shall occur, subject to the limitations provided
for herein. No adjustment shall be made in the number or kind of Securities or other securities which may be acquired on the exercise
of a Warrant unless it would result in a change of at least one-hundredth of a Warrant Share or other security. Any adjustment which may
by reason of this paragraph not be required to be made shall be carried forward and then taken into consideration in any subsequent adjustment.

Despite any adjustments provided for herein
or otherwise, the Issuer shall not be required, upon the exercise of any Warrants, to issue fractional Warrant Shares or other securities
in satisfaction of its obligations hereunder. Any fractional Warrants shall be rounded down to the nearest whole number and the Holder
of such Warrants shall not be entitled to any compensation in respect of any fractional Warrant Share that is not issued.

Miscellaneous Provisions

Except as otherwise provided for herein, any
delivery or surrender of documents shall be valid and effective if delivered personally or if sent by registered letter postage prepaid,
and any notice shall be valid and effective if made in writing and transmitted as aforementioned or if transmitted by email with confirmed
receipt, in each case addressed to:

		(a)	if to the Issuer,

NIOCORP DEVELOPMENTS LTD.

7000 South Yosemite Street, Suite115

Centennial, CO 80112

Email: jashburn@niocorp.com

		(b)	if to the Holder, at its address appearing in the register of holders of Warrants maintained by the Issuer,

and such shall be deemed to have been effectively
made and received on the date of personal delivery, if delivered; on the fourth business day after the time of mailing or upon actual
receipt, whichever is sooner, if sent by registered letter (except the delivery of documents to exercise the Warrants, in which case actual
receipt is required); or on the first business day after the time of email transmission, if sent by email. In the case of a disruption
in postal services, any delivery or surrender of documents or notice sent by mail shall not be deemed to have been effectively made or
received until it is actually delivered. The Issuer and the Holder may from time to time change their address for service hereunder by
notice in writing delivered in one of the foregoing manners.

Except as herein provided, any and all of the
rights conferred upon the Holder herein may be enforced by the Holder through appropriate legal proceedings. No recourse under or upon
any covenant, obligation or agreement herein contained shall be had against any shareholder, officer or director of the Issuer, either
directly or through the Issuer, it being expressly agreed and declared that the obligations under the Warrants are solely corporate obligations
of the Issuer and no personal liability whatsoever shall attach to or be incurred by the shareholders, officers or directors of the Issuer
in respect thereof. This Warrant Certificate shall be binding upon the Issuer and its successors.

This Warrant Certificate shall be governed
in accordance with the laws of British Columbia and the laws of Canada applicable therein. The parties hereby attorn to the jurisdiction
of the courts of British Columbia in the event of any dispute hereunder. Time shall be of the essence hereof.

Any alteration, amendment or revision to this
Warrant Certificate may only be made by a written agreement between the Issuer and the Holder.

    	 	 	 

    	 	-5-	 

    

For the purposes hereof, “business day”
means any day except Saturday, Sunday or a statutory holiday in Vancouver, British Columbia and, if any period expires or any day on which
any action is to be taken under this Warrant Certificate falls on a day which is not a business day, it shall be deemed to refer to the
next business day.

All amounts of money referred to in this Warrant
Certificate are expressed in lawful money of Canada.

If any covenant or provision herein or any
portion hereof is determined to be void, unenforceable or prohibited by the law of any province or the local requirements of any provincial
or federal government authority, such shall not be deemed to affect or impair the validity of any other covenant or provision herein or
a portion thereof, as the case may be, nor the validity of such covenant or provision or a portion thereof, as the case may be, in any
other jurisdiction.

This Warrant Certificate and all of its provisions
shall enure to the benefit of the Holder and its successors or personal representatives and shall be binding upon the Issuer, its successors
and permitted assigns.

[Remainder of page intentionally left blank.]

    	 	 	 

    	 	 	 

    

IN WITNESS WHEREOF the Issuer has caused this
Warrant Certificate to be signed by its duly authorized officer on the Issuance Date.

NIOCORP DEVELOPMENTS LTD.

 

	By:	 	 
	 	Authorized Signatory	 

 

 

 

[Warrant Certificate]

 

 

 

    	 	 	 

    	 	 	 

    

SCHEDULE “A” TO WARRANT CERTIFICATE

SUBSCRIPTION FORM

		TO:	NIOCORP DEVELOPMENTS LTD. (the “Issuer”)

7000 South Yosemite Street, Suite115

Centennial, CO 80112

 

The Undersigned, being the registered holder
of the attached Warrant Certificate of the Issuer, does hereby irrevocably exercise __________________ of the Warrants evidenced thereby
in accordance with the terms thereof, and accordingly hereby irrevocably subscribes for the Warrant Shares (as described therein) to be
received thereon and irrevocably surrenders the Warrant Certificate to the Issuer for such purpose. The Undersigned hereby irrevocably
directs that the Warrant Shares to be received by the Undersigned be registered as follows:

	Name in Full	Address	No. of

Warrant Shares
	1.	 	 
	 	 
	2.	 	 
	 	 
	3.	 	 
	 	 

IF WARRANT SHARES ARE TO BE ISSUED TO
A PERSON OR PERSONS OTHER THAN THE UNDERSIGNED REGISTERED HOLDER, THE SIGNATURE OF THE UNDERSIGNED MUST BE MEDALLION GUARANTEED
AND IT MUST PAY TO THE ISSUER ALL APPLICABLE TAXES AND OTHER DUTIES.

The Undersigned registered holder hereby represents,
warrants and certifies that:

		1.	the Undersigned is resident in the jurisdiction indicated as its address set forth in this Subscription
Form;

		2.	the Undersigned acknowledges that the Warrants and Warrant Shares (collectively, the “Securities”)
have not been registered under the United States Securities Act of 1933, as amended (the “1933 Act”),
or any applicable State securities laws and may not be offered or sold in the United States or to U.S. Persons without registration under
the 1933 Act and any applicable State securities laws, unless an exemption from registration is available;

		3.	the Undersigned has made reasonable inquiry into the jurisdiction of residence of all persons to whom
Warrant Shares are to be issued hereunder, and none of such persons is a person in the United States or a U.S. Person;

		4.	the Undersigned does not have any agreement or understanding (written or oral) with any person in the
United States or a U.S. Person respecting:

		(a)	the transfer or assignment of any rights or interest in any of the Securities;

		(b)	the division of profits, losses, fees, commissions, or any financial stake in connection with any of the
Securities; or

		(c)	the voting of the Warrant Shares to be issued hereunder; and

    	 	 	 

    	 	 -8-	 

    

		5.	the Undersigned has no intention to distribute, either directly or indirectly, any of the Securities in
the United States or to U.S. Persons.

DATED the ______ day of ______________, 20_____.

 

	 	}

}

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	Signature of Witness

[Please Note Instruction 2]	Signature of registered holder or Signatory thereof
	 	If applicable, print Name and Office of Signatory
	Print Name of Witness	Print Name of registered holder as on certificate
	Address of Witness	Street Address
	Occupation of Witness	City, Province and Postal Code

INSTRUCTIONS: 

1.                   The
registered holder of a Warrant may exercise its right to purchase Warrant Shares by completing and surrendering this Subscription Form
and the ORIGINAL Warrant Certificate representing the Warrant being exercised to the Issuer, together with the aggregate amount of the
exercise price for the Warrant Shares as provided for in the Warrant Certificate. Certificates representing the Warrant Shares to be
acquired on exercise will be sent by prepaid ordinary mail to the address(es) above within five business days after the receipt of all
required documentation.

2.                  
If this Subscription Form indicates that Warrant Shares are to be issued to a person or persons other than the registered holder
of the Warrants being exercised: (i) the signature of the registered holder on this Subscription Form must be medallion guaranteed by
an authorized officer of a chartered bank, trust company or an investment dealer who is a member of a recognized stock exchange, and (ii)
the registered holder must pay to the Issuer all applicable taxes and other duties.

3.                  
If this Subscription Form is signed by a trustee, executor, administrator, custodian, guardian, attorney, officer of a corporation
or any other person acting in a fiduciary or representative capacity, this Subscription Form must be accompanied by evidence of authority
to sign satisfactory to the Issuer.

    	 	 	 

    	 	 -9-	 

    

 

SCHEDULE “B” TO WARRANT CERTIFICATE

WARRANT TRANSFER FORM

For value received, the undersigned Transferor
hereby sells, transfers and assigns unto:

	 	(please print name of Transferee)	 

 

	of	 	 
	 	 	 
	 	(please print address of Transferee)	 

________________________________________________________
Warrants represented by the within certificate.

(please insert number of Warrants to be transferred).

DATED this ______ day of ______________, 20____.

	 	 
	 	Signature of Transferor

NOTICE: THE SIGNATURE TO THIS TRANSFER
MUST CORRESPOND WITH THE NAME AS WRITTEN UPON THE FACE OF THE WARRANT CERTIFICATE, IN EVERY PARTICULAR, WITHOUT ALTERATION, ENLARGEMENT
OR ANY CHANGE WHATEVER.

Signature guaranteed by: __________________________________________

NOTICE: THE SIGNATURE OF THE TRANSFEROR SHOULD
BE GUARANTEED BY A BANK, FINANCIAL INSTITUTION OR STOCK BROKER WHOSE SIGNATURE IS ACCEPTABLE TO THE ISSUER.

WARRANTS SHALL ONLY BE TRANSFERABLE IN ACCORDANCE
WITH APPLICABLE LAWS, AND THE RESALE OF WARRANTS AND COMMON SHARES ISSUABLE UPON EXERCISE OF WARRANTS MAY BE SUBJECT TO RESTRICTIONS UNDER
SUCH LAWS.

REPRESENTATIONS OF TRANSFEREE

The undersigned Transferee hereby certifies
it is a bona fide resident of the jurisdiction set forth above for its address, and that either (A)(i) at the time of this
transfer, it is not a U.S. Person and did not execute this Warrant Transfer Form while within the United States, (ii) it is not taking
transfer of any of the Warrants represented by the Transfer Form by or on behalf of any U.S. Person or any person who is within the United
States, and (iii) this transfer in all other respects complies with the terms of Regulation S; or (B)(i) it was an original purchaser
in the Issuer's private placement of the Units under which the Warrants were issued, (ii) it is an “Accredited Investor” as
defined in Rule 501(a) under the United States Securities Act of 1933, as amended (the “U.S. Securities Act”), and
(iii) the representations and warranties made to the Issuer in connection with the acquisition of the Units remain true and correct on
the date of this Warrant Transfer Form; or (C) the undersigned Transferee is delivering a written opinion of U.S. Counsel to the
effect that the transfer of the Warrants contemplated hereby has been registered under the U.S. Securities Act, or is exempt from registration
thereunder.

	 	 
	 	Signature of Transferor
	 	Name (Please Print)
	 	Date

 

    	 	 	 

    	 	 -10-	 

    

This Page intentionally left blankExhibit 4.5

UNLESS PERMITTED UNDER SECURITIES LEGISLATION,
THE HOLDER OF THIS SECURITY MUST NOT TRADE THE SECURITY BEFORE SEPTEMBER 11, 2021.

THE BROKER WARRANTS REPRESENTED HEREBY ARE
EXERCISABLE AT ANY TIME AND TIME TO TIME ON OR BEFORE 5:00 P.M. (VANCOUVER TIME) ON MAY 10, 2023 AFTER WHICH TIME THEY SHALL EXPIRE AND
BE OF NO FURTHER FORCE OR EFFECT.

NON-TRANSFERABLE BROKER WARRANTS TO PURCHASE
COMMON SHARES

OF

NIOCORP DEVELOPMENTS LTD.

(incorporated under the laws of British Columbia)

	
    Certificate No.:        BW-2021-001

    Number of Warrants:77,961
	
    Date: May 10, 2021

     

THIS CERTIFIES THAT,
for value received, Research Capital Corporation (the “Holder”), being the registered holder of 77,961 non-transferrable
broker warrants (the “Broker Warrants”), is entitled, at any time prior to 5:00 p.m. (Vancouver time) on the Expiry
Day (as defined below) to subscribe for and purchase the number of common shares (the “Common Shares”) of NioCorp Developments
Ltd. (the “Company”) set forth above on the basis of one Common Share at a price of $1.63 (the “Exercise Price”)
for each Broker Warrant exercised, subject to adjustment as set out herein, by surrendering to the Company at its principal office, 7000
South Yosemite Street, Suite 115, Centennial, CO 80112, this Broker Warrant certificate (the “Broker Warrant Certificate”),
with a completed and executed Subscription Form (as defined herein), and payment in full for the Common Shares being purchased.

The Company shall treat
the Holder as the absolute owner of this Broker Warrant for all purposes and the Company shall not be affected by any notice or knowledge
to the contrary. The Holder shall be entitled to the rights evidenced by this Broker Warrant free from all equities and rights of set-off
or counterclaim between the Company and the Holder and all persons may act accordingly and the receipt by the Holder of the Common Shares
issuable upon exercise hereof shall be a good discharge to the Company and the Company shall not be bound to inquire into the title of
any such Holder.

		1.	Definitions: In this Broker Warrant Certificate, unless there is something in the subject
matter or context inconsistent therewith, the following expressions shall have the following meanings namely:

		(a)	“Adjustment Period” means the period commencing on the date hereof and ending at the
Expiry Time;

		(b)	“Broker Warrant Certificate” means this Broker Warrant certificate;

		(c)	“Broker Warrant” means a non-transferable broker warrant exercisable to purchase one
Common Share at the Exercise Price until the Expiry Time;

		(d)	“Business Day” means any day other than a Saturday, Sunday, legal holiday or a day
on which banking institutions are closed in Toronto, Ontario or Vancouver, British Columbia;

		(e)	“Common Share” means the common shares in the capital of the Company.

		(f)	“Company” means NioCorp Developments Ltd., a company incorporated under the laws of
British Columbia and its successors and assigns;

    	 	 	 

     

    

		(g)	“Current Market Price” of a Common Share at any date means the price per share equal
to the volume weighted average price at which the Common Shares have traded on the TSX or,
if the Common Shares are not listed on the TSX, on any other stock exchange on which such shares are then listed as may be selected by
the directors of the Company, for the five Trading Days ending three Trading Days prior to the relevant date or, if the Common Shares
are not listed on any stock exchange, then on the over-the-counter market with the volume weighted average price per Common Share being
determined by dividing the aggregate sale price of all Common Shares sold on the said exchange or market, as the case may be, during the
said five Trading Days by the aggregate number of Common Shares so sold or, if the Common Shares are not listed or quoted on any stock
exchange or over-the-counter market, such price as may be determined by such firm of independent charted accountants as may be selected
by the directors of the Company;

		(h)	“Dividends Paid in the Ordinary Course” means dividends paid in any financial year
of the Company, whether in (i) cash; (ii) shares of the Company; (iii) warrants or similar rights to purchase any shares of the Company
or property or other assets of the Company provided that the value of such dividends does not in such financial year exceed the greater
of:

		(i)	150% of the aggregate amount of dividends paid by the Company on the Common Shares in the 12-month period
ending immediately prior to the first day of such financial year; and

		(ii)	100% of the consolidated net earnings from continuing operations of the Company, before any extraordinary
items, for the 12-month period ending immediately prior to the first day of such financial year (such consolidated net earnings from continuing
operations to be computed in accordance with generally accepted accounting principles in Canada);

		(i)	“Exercise Price” means $1.63 per Common Share, subject to adjustment in accordance
with Section 10 hereof;

		(j)	“Expiry Day” means May 10, 2023;

		(k)	“Expiry Time” means 5:00 p.m. (Vancouver time), on the Expiry Day;

		(l)	“Holder” shall have the meaning ascribed thereto on the face page hereof;

		(m)	“person” means an individual, corporation, partnership,
unincorporated association, unincorporated syndicate, unincorporated organization, trust, trustee, executor, administrator, or other legal
representative;

		(n)	“Rights Offering” has the meaning set out in Section 10(b)(ii) in this Broker Warrant
Certificate;

		(o)	“Subscription Form” means the subscription form annexed to this Broker Warrant Certificate;

		(p)	“TSX” means the Toronto Stock Exchange;

		(q)	“Trading Day” with respect to a stock exchange, market or over-the-counter market means
a day on which such stock exchange or over-the-counter market is open for business;

    	 	 2	 

     

    

		(r)	“United States” means the United States of America, its territories and possessions,
any state of the United States, and the District of Columbia;

		(s)	“U.S. Person” means U.S. person as that term is defined in Regulation S under the U.S.
Securities Act;

		(t)	“U.S. Securities Act” means the United States Securities Act of 1933, as amended; and

		(u)	“$” means Canadian Dollars.

		2.	Expiry Time: At the Expiry Time, all rights under the Broker Warrants evidenced hereby,
in respect of which the right of subscription and purchase herein provided for shall not theretofore have been exercised, shall expire
and be void and of no further force and effect.

		3.	Exercise Procedure:

		(a)	The Holder may exercise the right to subscribe and purchase the number of Common Shares herein provided,
by delivering to the Company prior to the Expiry Time at its principal office this Broker Warrant Certificate, with the Subscription Form
duly completed and executed by the Holder or its legal representative or attorney, duly appointed by an instrument in writing in form
and manner satisfactory to the Company, together with a certified cheque or bank draft payable to or to the order of the Company in an
amount equal to the aggregate Exercise Price in respect of the Broker Warrants so exercised. Any Broker Warrant Certificate so surrendered
shall be deemed to be surrendered only upon delivery thereof to the Company at its principal office set forth herein in the manner provided
in Section 24 hereof (or to such other address as the Company may notify the Holder).

		(b)	Upon such delivery and payment as aforesaid, the Company shall cause to be issued to the Holder hereof
the Common Shares subscribed for not exceeding those which such Holder is entitled to purchase pursuant to this Broker Warrant Certificate
and the Holder hereof shall become a shareholder of the Company in respect of the Common Shares subscribed for with effect from the date
of such delivery and payment and shall be entitled to delivery of a certificate evidencing the Common Shares and the Company shall cause
such certificates to be mailed to the Holder hereof at the address or addresses specified in such subscription as soon as practicable,
and in any event within five (5) Business Days of such delivery and payment.

		(c)	In the event that any Broker Warrants are exercised before September 11, 2021, the certificate(s) representing
the Common Shares issued upon such exercise shall bear the following legend:

“UNLESS PERMITTED
UNDER SECURITIES LEGISLATION, THE HOLDER OF THIS SECURITY MUST NOT TRADE THE SECURITY BEFORE SEPTEMBER 11, 2021.”

provided that, if at
any time, in the opinion of counsel to the Company, such legend is no longer necessary or advisable under any such securities laws, or
the holder of any such legended certificate, provides the Company with evidence satisfactory in form and substance to the Company (which
may include an opinion of counsel satisfactory to the Company) to the effect that such legends are not required, such legended certificate
may thereafter be surrendered to the Company in exchange for a certificate which does not bear such legend.

    	 	 3	 

     

    

		(d)	The Broker Warrants shall not be exercised by, or for the account or benefit of, any person in the United
States or any “U.S. person” (a “U.S. Person”) as defined in Rule 902(k) of Regulation S under the U.S.
Securities Act during any time that no Registration Statement (as defined below) registering the Warrants and the Common Shares issuable
upon the exercise of the Broker Warrant evidenced hereby is effective, unless an exemption from the registration requirements of the U.S.
Securities Act is available and such holder provides evidence of the availability of such exemption satisfactory to the Company, and the
certificate representing the Common Shares issued upon such exercise, if then required pursuant to Rule 144 of the U.S. Securities Act,
shall bear the following legend:

“THE SECURITIES
REPRESENTED HEREBY HAVE NOT BEEN AND WILL NOT BE REGISTERED UNDER THE UNITED STATES SECURITIES ACT OF 1933, AS AMENDED (THE “U.S.
SECURITIES ACT”), OR UNDER ANY STATE SECURITIES LAWS. THE HOLDER HEREOF, BY PURCHASING THESE SECURITIES, AGREES FOR THE BENEFIT
OF NIOCORP DEVELOPMENTS LTD. (THE “COMPANY”), THAT THESE SECURITIES MAY BE OFFERED, SOLD, PLEDGED OR OTHERWISE TRANSFERRED,
DIRECTLY OR INDIRECTLY ONLY (A) TO THE COMPANY, (B) IF THE SECURITIES HAVE BEEN REGISTERED IN COMPLIANCE WITH THE REGISTRATION REQUIREMENTS
UNDER THE SECURITIES ACT AND IN ACCORDANCE WITH APPLICABLE STATE SECURITIES LAWS (C) IN COMPLIANCE WITH THE EXEMPTION FROM THE REGISTRATION
REQUIREMENTS UNDER THE SECURITIES ACT IN ACCORDANCE WITH RULE 144 THEREUNDER, IF APPLICABLE, AND IN ACCORDANCE WITH APPLICABLE STATE SECURITIES
LAWS, OR (D) IN A TRANSACTION THAT DOES NOT REQUIRE REGISTRATION UNDER THE SECURITIES ACT OR ANY APPLICABLE STATE LAWS AND REGULATIONS
GOVERNING THE OFFER AND SALE OF SECURITIES, AND, IN EACH CASE, THE HOLDER HAS, PRIOR TO SUCH SALE, FURNISHED TO THE COMPANY AN OPINION
OF COUNSEL OF RECOGNIZED STANDING, OR OTHER EVIDENCE OF EXEMPTION, REASONABLY SATISFACTORY TO THE COMPANY TO SUCH EFFECT. HEDGING TRANSACTIONS
INVOLVING THE SECURITIES ARE PROHIBITED EXCEPT IN COMPLIANCE WITH THE SECURITIES ACT. THESE SECURITIES MAY NOT CONSTITUTE “GOOD
DELIVERY” IN SETTLEMENT OF TRANSACTIONS ON CANADIAN STOCK EXCHANGES.”

provided that, if at
any time, in the opinion of counsel to the Company, such legend is no longer necessary or advisable under any such securities laws, or
the holder of any such legended certificate, provides the Company with evidence satisfactory in form and substance to the Company (which
may include an opinion of counsel satisfactory to the Company) to the effect that such legends are not required, such legended certificate
may thereafter be surrendered to the Company in exchange for a certificate which does not bear such legend.

		(e)	Prior to effectiveness of a registration statement (the “Registration Statement”) under
the U.S. Securities Act, including any amendments or supplements thereto, registering the Warrants and the Common Shares issuable upon
the exercise of the Warrants and at any time the Registration Statement ceases to be effective, prior to the Expiry Time and for so long
as the Registration Statement is not effective, the Holder may exercise this Broker Warrant as set forth in Section 3(a). Within three
business days of notice from the Holder of the election to exercise while no Registration Statement is effective, the Corporation shall
elect, at its sole discretion, to either (a) redeem the Broker Warrants, or (b) permit the cashless exercise of the Broker Warrants. If
the Holder exercises the right provided for in

    	 	 4	 

     

    

this Section 3(e) in respect of a lesser
number of Broker Warrants than the aggregate number of Broker Warrants represented by the Broker Warrant Certificate surrendered, the
Holder shall be entitled to receive a further Broker Warrant Certificate in respect of the Broker Warrants represented by the Broker Warrant
Certificate that have not been part of a cashless exercise or redeemed.

		(f)	In the event Holder exercises this Broker Warrant in accordance with Section 3(e), the Corporation shall,
within three business days, either (i) redeem the Broker Warrants, or (ii) permit the cashless exercise of the Broker Warrants, each as
provided in this Section 3(f) and the Corporation shall cause either (a) in the case of a redemption, a cheque in the amount of money
determined by multiplying the number of Common Shares that would have been issued if the Broker Warrants to be redeemed were exercised
on the Determination Date (as defined below) by the excess (if any) of the Current Market Price per Common Share on the date (the “Determination
Date”) of execution by the Holder of the Subscription Form, over the exercise price of the Broker Warrant, or (b) in the case of
a cashless exercise, a certificate representing the number of Common Shares equal to the quotient obtained by dividing: (A) (i) the Current
Market Price per Common Share on the Determination Date minus the Exercise Price; (ii) multiplied by the number of Common Shares which
would, but for such cashless exercise, have been issued, by (B) the Current Market Price of the Common Shares on the Determination Date,
to be mailed to such Holder at the address specified in Subscription Form, or, if so specified in such Subscription Form, to be made available
for pick-up by such Holder at the Company or its transfer agent.

		4.	Partial Exercise: The Holder may subscribe for and purchase a number of Common Shares less
than the maximum number the Holder is entitled to purchase pursuant to the full exercise of this Broker Warrant Certificate. In the event
of any such subscription prior to the Expiry Time, the Holder shall be entitled to receive, without charge, a new Broker Warrant Certificate
in respect of the balance of the Common Shares which the Holder was entitled to subscribe for pursuant to this Broker Warrant Certificate
and which were then not purchased.

		5.	No Fractional Shares: Notwithstanding any adjustments provided for in Section 10 hereof
or otherwise, the Company shall not be required upon the exercise of any Broker Warrants to issue fractional Common Shares in satisfaction
of its obligations hereunder and, in any such case, the number of Common Shares issuable upon the exercise of any Broker Warrants shall
be rounded down to the nearest whole number. The Company shall not be required to make any payment to the Holder who, absent this Section
5 hereof, would otherwise have been entitled to receive a fractional Common Share.

		6.	Limitation on Transfer:  The Broker Warrants are non-transferable and non-assignable.

		7.	Not a Shareholder: Nothing in this Broker Warrant Certificate or in the holding of a Broker
Warrant evidenced hereby shall be construed as conferring upon the Holder any right or interest whatsoever as a shareholder of the Company
or any other right or interest except as herein expressly provided.

		8.	No Obligation to Purchase: Nothing herein contained or done pursuant hereto shall obligate
the Holder to subscribe for or the Company to issue any shares except those shares in respect of which the Holder shall have exercised
its right to purchase hereunder in the manner provided herein.

    	 	 5	 

     

    

		9.	Covenants:

		(a)	The Company covenants and agrees that so long as any Broker Warrants evidenced hereby remain outstanding,
it shall reserve and there shall remain unissued out of its authorized capital a sufficient number of Common Shares to satisfy the right
of purchase herein provided for, it will cause the Common Shares subscribed for and purchased in the manner herein provided to be issued
and delivered as directed and such Common Shares shall be issued as fully paid and non-assessable Common Shares and free from all taxes,
liens and charges with respect to the issue thereof and the holders thereof shall not be liable to the Company or to its creditors in
respect thereof.

		(b)	The Company covenants and agrees that until the Expiry Time, while the Broker Warrants (or remaining portion
thereof) shall be outstanding, the Company shall use its best efforts to preserve and maintain its corporate existence, to carry on and
conduct its business in a prudent manner in accordance with industry standards and good business practice, to remain listed on the TSX,
maintain its status as a “reporting issuer” not in default of the requirements of the applicable securities laws in the Canadian
jurisdictions in which the Company is currently a reporting issuer, provided that this covenant shall not prevent the Company from completing
any transaction which would result in the Company to cease its corporate existence, cease to be listed on the TSX or cease to be a reporting
issuer, respectively, so long as the holders of the Common Shares receive securities of an entity which is listed on a stock exchange
in Canada or cash or the holders of the Common Shares have approved the transaction in accordance with the requirements of applicable
corporate laws and the policies of the TSX.

		(c)	The Company shall use its best efforts to ensure the Common Shares are listed and posted for trading on
the TSX or such other stock exchange or over-the-counter market as the Common Shares may be listed or quoted (as the case may be) at the
time of exercise of the Broker Warrants. In addition, the Company shall make all requisite filings under applicable securities legislation
necessary to remain a reporting issuer not in default.

		(d)	If the issuance of the Common Shares upon the exercise of the Broker Warrants requires any filing or registration
with or approval of any securities regulatory authority or other governmental authority or compliance with any other requirement under
any law before such Common Shares may be validly issued (other than the filing of a prospectus or similar disclosure document), the Company
and the Holder agree to take such actions as may be necessary to secure such filing, registration, approval or compliance, as the case
may be.

		(e)	The Company will do, execute, acknowledge and deliver or cause to be done, executed, acknowledged and
delivered, all other acts, deeds and assurances in law as may be reasonably required for the better accomplishing and effecting of the
intentions and provisions of this Broker Warrant Certificate.

		10.	Adjustments:

		(a)	Adjustment: The rights of the holder of this Broker Warrant Certificate, including the number of
Common Shares issuable upon the exercise of such Broker Warrants evidenced hereunder, will be adjusted from time to time in the events
and in the manner provided in, and in accordance with the provisions of, this Section 10. The purpose and intent of the adjustments provided
for in this Section is to ensure that the rights and obligations of the Holder are neither diminished nor enhanced as a result of any
of the events set forth in paragraphs (b), (c) or (d) of this Section 10. Accordingly, the provisions of this Section 10 shall be interpreted
and applied in accordance with such purpose and intent.

    	 	 6	 

     

    

		(b)	The Exercise Price in effect at any date will be subject to adjustment from time to time as follows:

		(i)	Share Reorganization: If and whenever at any time during the Adjustment Period, the Company shall
(A) subdivide, redivide or change the outstanding Common Shares into a greater number of Common Shares, (B) consolidate, combine or reduce
the outstanding Common Shares into a lesser number of Common Shares, or (C) fix a record date for the issue of Common Shares or securities
convertible into or exchangeable for Common Shares to all or substantially all of the holders of Common Shares by way of a stock dividend
or other distribution other than a Dividend Paid in the Ordinary Course, then, in each such event, the Exercise Price shall, on the record
date for such event or, if no record date is fixed, the effective date of such event, be adjusted so that it will equal the rate determined
by multiplying the Exercise Price in effect immediately prior to such date by a fraction, of which the numerator shall be the total number
of Common Shares outstanding on such date before giving effect to such event, and of which the denominator shall be the total number of
Common Shares outstanding on such date after giving effect to such event (including, in the case where securities exchangeable for or
convertible into Common Shares are distributed, the number of Common Shares that would have been outstanding had such securities been
fully exchanged for or converted into Common Shares on such record date or effective date). Such adjustment shall be made successively
whenever any such event shall occur. Any such issue of Common Shares by way of a stock dividend shall be deemed to have been made on the
record date for such stock dividend for the purpose of calculating the number of outstanding Common Shares under paragraphs 10(b)(i) and
(ii) hereof.

		(ii)	Rights Offering: If and whenever at any time during the Adjustment Period, the Company shall fix
a record date for the issue of rights, options or warrants to all or substantially all of the holders of Common Shares entitling the holders
thereof, within a period expiring not more than 45 days after the record date for such issue, to subscribe for or purchase Common Shares
(or securities convertible into or exchangeable for Common Shares) at a price per share (or having a conversion or exchange price per
share) less than 95% of the Current Market Price on such record date (each such event, a “Rights Offering”), then the
Exercise Price shall be adjusted immediately after such record date so that it will equal the rate determined by multiplying the Exercise
Price in effect on such record date by a fraction, of which the numerator shall be the total number of Common Shares outstanding on such
record date plus the number of Common Shares equal to the number arrived at by dividing the aggregate price of the total number of additional
Common Shares so offered for subscription or purchase (or the aggregate conversion or exchange price of the convertible or exchangeable
securities so offered) by such Current Market Price, and of which the denominator shall be the total number of Common Shares outstanding
on such record date plus the total number of additional Common Shares so offered for subscription or purchase (or into or for which the
convertible or exchangeable securities so offered are convertible or exchangeable). Any Common Shares owned by or held for the account
of the Company or any subsidiary of the Company shall be deemed not to be outstanding for the purpose of any such computation. Such adjustment
shall be made successively whenever such a record date is fixed, provided that if two or more such record dates referred to in this subsection
10(b)(ii) are fixed within a period of 25 Trading Days, such adjustment will be made successively as if each of such record dates occurred
on the earliest of such record dates. To the extent that any such rights, options or

    	 	 7	 

     

    

warrants are not exercised prior to
the expiration thereof, the Exercise Price shall then be readjusted to the Exercise Price which would then be in effect based upon the
number of Common Shares (or securities convertible into or exchangeable for Common Shares) actually issued upon the exercise of such rights,
options or warrants, as the case may be.

		(iii)	Distribution: If and whenever at any time during the Adjustment Period, the Company shall fix a
record date for the making of a distribution to all or substantially all of the holders of Common Shares of (A) shares of any class other
than Common Shares whether of the Company or any other corporation, (B) rights, options or warrants to acquire Common Shares or securities
exchangeable for or convertible into Common Shares or property or other assets of the Company (other than a Rights Offering as described
in Section 10(b)(ii)), (C) evidences of indebtedness, or (D) cash, securities or other property or assets then, in each such case, provided
that such distribution does not constitute a Dividend Paid in the Ordinary Course or fall under clauses (i) or (ii) of this Section 10
above, the Exercise Price will be adjusted immediately after such record date so that it will equal the rate determined by multiplying
the Exercise Price in effect on such record date by a fraction, of which the numerator shall be the total number of Common Shares outstanding
on such record date multiplied by the Current Market Price on the earlier of such record date and the date on which the Company announces
its intention to make such distribution, less the aggregate fair market value (as determined by the directors, acting reasonably, at the
time such distribution is authorized, and subject to TSX acceptance) of such shares or rights, options or warrants or evidences of indebtedness
or cash, securities or other property or assets so distributed, and of which the denominator shall be the total number of Common Shares
outstanding on such record date multiplied by such Current Market Price. Any Common Shares owned by or held for the account of the Company
or any subsidiary of the Company shall be deemed not to be outstanding for the purpose of any such computation. Such adjustment shall
be made successively whenever such a record date is fixed, provided that if two or more such record dates or record dates referred to
in this subsection 10(b)(iii) are fixed within a period of 25 Trading Days, such adjustment will be made successively as if each of such
record dates occurred on the earliest of such record dates. To the extent that any such rights, options or warrants so distributed are
not exercised prior to the expiration thereof, the Exercise Price shall then be readjusted to the Exercise Price which would then be in
effect based upon such rights, options or warrants or evidences of indebtedness or cash, securities or other property or assets actually
distributed or based upon the number or amount of securities or the property or assets actually issued or distributed upon the exercise
of such rights, options or warrants, as the case may be.

		(c)	Reclassifications: If and whenever at any time during the Adjustment Period, there is (A) any reclassification
of or amendment to the outstanding Common Shares, any change of the Common Shares into other shares or any other reorganization of the
Company (other than as described in subsection 10(b) hereof), (B) any consolidation, amalgamation, arrangement, merger or other form of
business combination of the Company with or into any other corporation resulting in any reclassification of the outstanding Common Shares,
any change of the Common Shares into other shares or any other reorganization of the Company, or (C) any sale, lease, exchange or transfer
of the undertaking or assets of the Company as an entirety or substantially as an entirety to another corporation or entity, then, in
each such event, the Holder of the Broker Warrants evidenced hereby which are thereafter exercised shall be entitled to receive, and shall
accept, in lieu of the number of

    	 	 8	 

     

    

Common Shares to which such Holder was
theretofore entitled upon such exercise, the kind and number or amount of shares or other securities or property which such Holder would
have been entitled to receive as a result of such event if, on the effective date thereof, such Holder had been the registered holder
of the number of Common Shares to which such Holder was theretofore entitled upon such exercise. If necessary as a result of any such
event, appropriate adjustments will be made in the application of the provisions set forth in this subsection with respect to the rights
and interests thereafter of the Holder of this Broker Warrant Certificate to the end that the provisions set forth in this subsection
will thereafter correspondingly be made applicable, as nearly as may reasonably be, in relation to any shares or other securities or property
thereafter deliverable upon the exercise of the Broker Warrants. Any such adjustments will be made by and set forth in an instrument supplemental
hereto approved by the directors, acting reasonably, and shall for all purposes be conclusively deemed to be an appropriate adjustment.
No reclassification in accordance with this subsection 10(c) shall be completed unless all necessary steps shall have been taken so that
the Holders of the Broker Warrants shall thereafter be entitled to receive the number of Common Shares or other securities or property
of the Company or of the continuing, successor or purchasing person, as the case may be, under the reclassification, subject to adjustment
thereafter in accordance with provisions the same, as nearly as may be possible, as those contained in this Section 10.

		(d)	If at any time during the Adjustment Period any adjustment or readjustment in the Exercise Price shall
occur pursuant to the provisions of subsection 10(b) or 10(c) of this Broker Warrant Certificate, then the number of Common Shares
purchasable upon the subsequent exercise of the Broker Warrants shall be simultaneously adjusted or readjusted, as the case may be, by
multiplying the number of Common Shares purchasable upon the exercise of the Broker Warrants immediately prior to such adjustment or readjustment
by a fraction which shall be the reciprocal of the fraction used in the adjustment or readjustment of the Exercise Price.

		11.	Rules Regarding Calculation of Adjustment of Exercise Price:

		(a)	The adjustments provided for in Section 10 are cumulative and will, in the case of adjustments to the
Exercise Price, be computed to the nearest whole Common Share and will be made successively whenever an event referred to therein occurs,
subject to the following subsections of this Section 11.

		(b)	No adjustment in the Exercise Price is required to be made unless such adjustment would result in a change
of at least 1% in the prevailing Exercise Price and no adjustment in the Exercise Price is required unless such adjustment would result
in a change of at least one one-hundredth of a Common Share; provided, however, that any adjustments which, except for the provisions
of this subsection, would otherwise have been required to be made, will be carried forward and taken into account in any subsequent adjustments.

		(c)	No adjustment in the Exercise Price will be made in respect of any event described in Section 10, other
than the events referred to in subsection 10(c), if the Holder is entitled to participate in such event on the same terms, mutatis
mutandis, as if the Holder had exercised this Broker Warrant prior to or on the effective date or record date of such event. Any participation
by the Holder in a distribution, dividend, or other event referred to in Section 10 is subject to the approval of the TSX.

		(d)	No adjustment in the Exercise Price will be made under Section 10 in respect of the issue from time to
time of Common Shares issuable from time to time as Dividends Paid in the Ordinary Course to holders of Common Shares who exercise an
option or election to

    	 	 9	 

     

    

receive substantially equivalent dividends
in Common Shares in lieu of receiving a cash dividend.

		(e)	If at any time a question or dispute arises with respect to adjustments provided for in Section 10, such
question or dispute will be conclusively determined by such firm of independent chartered accountants as may be selected by action of
the directors of the Company and any such determination, subject to regulatory approval and absent manifest error, will be binding upon
the Company and the Holder. The Company will provide such chartered accountant with access to all necessary records of the Company.

		(f)	In case the Company after the date of issuance of this Broker Warrant Certificate takes any action affecting
the Common Shares, other than any action described in Section 10, which in the reasonable opinion of the board of directors of the Company
would materially affect the rights of the Holder, the Exercise Price will be adjusted in such manner, if any, and at such time, by action
of the directors of the Company in their sole discretion, acting reasonably and in good faith, as such directors deem equitable, but subject
in all cases to any necessary regulatory approval. Failure of the taking of action by the directors of the Company so as to provide for
an adjustment on or prior to the effective date of any action by the Company affecting the Common Shares will be conclusive evidence that
the board of directors of the Company has determined that it is equitable to make no adjustment in the circumstances.

		(g)	If the Company sets a record date to determine the holders of the Common Shares for the purpose of entitling
them to receive any dividend or distribution or sets a record date to take any other action and, thereafter and before the distribution
to such shareholders of any such dividend or distribution or the taking of any other action, decides not to implement its plan to pay
or deliver such dividend or distribution or take such other action, then no adjustment in the Exercise Price will be required by reason
of the setting of such record date.

		(h)	In the absence of a resolution of the directors of the Company fixing a record date for any event which
would require any adjustment to the Broker Warrants, the Company will be deemed to have fixed as the record date therefor the date on
which the event is effected.

		(i)	As a condition precedent to the taking of any action which would require any adjustment to the Common
Shares issuable under the Broker Warrants, including the Exercise Price, the Company shall take any corporate action which may be necessary
in order that the Company or any successor to the Company or successor to the undertaking or assets of the Company have unissued and reserved
in its authorized capital and may validly and legally issue as fully paid and non-assessable all the shares or other securities which
the Holder is entitled to receive on the full exercise thereof in accordance with the provisions hereof.

		(j)	The Company will from time to time, immediately after the occurrence of any event which requires an adjustment
or readjustment as provided in Section 10, forthwith give notice to the Holder specifying the event requiring such adjustment or readjustment
and the results thereof, including the resulting Exercise Price.

		(k)	The Company covenants to and in favour of the Holder that so long as any Broker Warrants evidenced hereby
remain outstanding, it will give notice to the Holder of the effective date or of its intention to fix a record date for any event referred
to in Section 10 whether or not such action would give rise to an adjustment in the Exercise Price or the number and type of securities
issuable upon the exercise of the Broker Warrants, and, in each case, such notice shall specify the particulars of such event and the
record date and the effective date

    	 	 10	 

     

    

for such event; provided that the Company
shall only be required to specify in such notice such particulars of such event as have been fixed and determined on the date on which
such notice is given. Such notice shall be given not less than 14 days in each case prior to such applicable record date or effective
date.

		(l)	In any case that an adjustment pursuant to Section 10 shall become effective immediately after a record
date for or an effective date of an event referred to herein, the Company may defer, until the occurrence and consummation of such event,
issuing to the Holder of this Broker Warrant Certificate, if exercised after such record date or effective date and before the occurrence
and consummation of such event, the additional Common Shares or other securities or property issuable upon such exercise by reason of
the adjustment required by such event, provided, however, that the Company will deliver to the Holder an appropriate instrument evidencing
the Holder’s right to receive such additional Common Shares or other securities or property upon the occurrence and consummation
of such event and the right to receive any dividend or other distribution in respect of such additional Common Shares or other securities
or property declared in favour of the holders of record of Common Shares or of such other securities or property on or after the Exercise
Date or such later date as the Holder would, but for the provisions of this subsection, have become the holder of record of such additional
Common Shares or of such other securities or property.

		(m)	On the happening of each and every such event set out in Section 10, the applicable provisions of this
Broker Warrant Certificate, including the Exercise Price, shall, ipso facto, be deemed to be amended accordingly and the Company shall
take all necessary action so as to comply with such provisions as so amended.

		12.	Consolidation and Amalgamation

		(a)	In the event that the Company enters into any transaction whereby all or substantially all of its undertaking,
property and assets would become the property of any other corporation (herein called a “successor corporation”) whether
by way of reorganization, reconstruction, consolidation, amalgamation, merger, transfer, sale, disposition or otherwise, the Company will
ensure that contemporaneously with the consummation of such transaction the Company and the successor corporation shall have executed
such instruments and done such things as the Company, acting reasonably, considers necessary or advisable to establish that upon the consummation
of such transaction:

		i.	the successor corporation will have assumed all the covenants and obligations of the Company under this
Broker Warrant Certificate, and

		ii.	the Broker Warrants and the terms set forth in this Broker Warrant Certificate will be a valid and binding
obligation of the successor corporation entitling the Holder, as against the successor corporation, to all the rights of the Holder under
this Broker Warrant Certificate.

		(b)	Whenever the conditions of subsection 12(a) shall have been duly observed and performed the successor
corporation shall possess, and from time to time may exercise, each and every right and power of the Company under the Broker Warrants
in the name of the Company or otherwise and any act or proceeding by any provision hereof required to be done or performed by any director
or officer of the Company may be done and performed with like force and effect by the like directors or officers of the successor corporation.

    	 	 11	 

     

    

		13.	Representation and Warranty: The Company hereby represents and warrants with and to the
Holder that the Company is duly authorized and has all corporate and lawful power and authority to create and issue the Broker Warrants
evidenced hereby and the Common Shares issuable upon the exercise hereof and perform its obligations hereunder and that this Broker Warrant
Certificate represents a valid, legal and binding obligation of the Company enforceable in accordance with its terms.

		14.	If Share Transfer Books Closed: The Company shall not be required to deliver certificates
for Common Shares while the share transfer books of the Company are properly closed, prior to any meeting of shareholders or for the payment
of dividends or for any other purpose and in the event of the surrender of any Broker Warrant in accordance with the provisions hereof
and the making of any subscription and payment for the Common Shares called for thereby during any such period delivery of certificates
for Common Shares may be postponed for a period not exceeding three (3) Business Days after the date of the re-opening of said share transfer
books provided that any such postponement of delivery of certificates shall be without prejudice to the right of the Holder, if the Holder
has surrendered the same and made payment during such period, to receive such certificates for the Common Shares called for after the
share transfer books shall have been re-opened.

		15.	Protection of Shareholders, Officers and Directors: Subject as herein provided, all or any
of the rights conferred upon the Holder may be enforced by the Holder by appropriate legal proceedings. No recourse under or upon any
obligation, covenant or agreement herein contained or in any of the Broker Warrants represented hereby shall be taken against any shareholder,
officer or director of the Company, either directly or through the Company, it being expressly agreed and declared that the obligations
under the Broker Warrants evidenced hereby, are solely corporate obligations of the Company and that no personal liability whatever shall
attach to or be incurred by the shareholders, officers, or directors of the Company or any of them in respect thereof, any and all rights
and claims against every such shareholder, officer or director being hereby expressly waived as a condition of and as a consideration
for the issue of the Broker Warrants evidenced hereby.

		16.	Replacement Certificate: Upon receipt of evidence satisfactory to the Company of loss, theft,
destruction or mutilation of this Broker Warrant Certificate and, if requested by the Company, upon delivery of a bond of indemnity satisfactory
to the Company (or, in the case of mutilation, upon surrender of this Broker Warrant Certificate), the Company will issue to the Holder
a replacement certificate containing the same terms and conditions as this Broker Warrant Certificate.

		17.	Governing Law: This Broker Warrant Certificate shall be governed by, and construed in accordance
with, the laws of the Province of British Columbia and the laws of Canada applicable therein but the references to such laws shall not,
by conflict of laws, rules or otherwise, require the application of the law of any jurisdiction other than the Province of British Columbia.

		18.	Severability: If any one or more of the provisions or parts thereof contained in this Broker
Warrant Certificate should be or become invalid, illegal or unenforceable in any respect in any jurisdiction, the remaining provisions
or parts thereof contained herein shall be and shall be conclusively deemed to be, as to such jurisdiction, severable therefrom.

		19.	Amendments: Subject to the approval of the TSX, the provisions of these Broker Warrants
may from time to time be amended, modified or waived, if such amendment, modification or waiver is in writing and consented to in writing
by the Company and the Holder.

		20.	Headings: The headings of the articles, sections, subsections and clauses of this Broker
Warrant Certificate have been inserted for convenience and reference only and do not define, limit, alter or enlarge the meaning of any
provision of this Broker Warrant Certificate.

    	 	 12	 

     

    

		21.	Numbering of Articles, etc.: Unless otherwise stated, a reference herein to a numbered or
lettered article, section, subsection, clause, subclause or schedule refers to the article, section, subsection, clause, subclause or
schedule bearing that number or letter in this Broker Warrant Certificate.

		22.	Gender: Whenever used in this Broker Warrant Certificate, words importing the singular number
only shall include the plural, and vice versa, and words importing the masculine gender shall include the feminine gender.

		23.	Day not a Business Day: In the event that any day on or before which any action is required
to be taken hereunder is not a Business Day, then such action shall be required to be taken on or before the requisite time on the next
succeeding day that is a Business Day.

		24.	Binding Effect: This Broker Warrant Certificate and all of its provisions shall enure to
the benefit of the Holder, its successors, assigns and legal personal representatives and shall be binding upon the Company and its successors.

		25.	Notice: Notice must be given by facsimile (in the case of notice to the Company), prepaid
same day courier, or hand delivery, and addressed as follows:

		(a)	If to the Holder at the latest address of the Holder as recorded on the books of the Company; and

		(b)	If to the Company at:

7000 South Yosemite Street

Suite 115

Centennial, CO 80112

		Attention:	Neal Shah, Chief Financial Officer

		Email:	nshah@niocorp.com

Unless herein otherwise expressly provided,
a notice to be given hereunder will be deemed to be validly given on the: (i) same day if notice is sent during regular business hours
in the recipient’s jurisdiction, or (ii) the next Business Day if notice is sent outside of regular business hours in the recipient’s
jurisdiction or on a day that is not a Business Day.

		26.	Time of Essence: Time shall be of the essence hereof.

[Signature page follows.]

    	 	 13	 

     

    

IN WITNESS WHEREOF
the Company has caused this Broker Warrant Certificate to be signed by its duly authorized officer as of this _10th ___ day
of May 2021.

 

	 	NIOCORP DEVELOPMENTS LTD.
	 	Per:	 
	 	 	Authorized Signing Officer

 

 

Broker Warrant Certificate

 

 

 

    	 	  	 

     

    

SUBSCRIPTION FORM

Capitalized terms used herein have the meanings
ascribed thereto in the Broker Warrant Certificate (the “Broker Warrant Certificate”) to which this Subscription Form
is attached.

The undersigned holder of the attached Broker
Warrant Certificate hereby subscribes for _______________ common shares (the “Common Shares”) of NioCorp Developments
Ltd. (the “Company”) pursuant to the terms of the Broker Warrant Certificate at the Exercise Price on the terms specified
in the Broker Warrant Certificate and contemporaneously with the execution and delivery hereof makes payment therefor on the terms specified
in the Broker Warrant Certificate. If any Broker Warrants represented by this Broker Warrant Certificate are not being exercised, a new
Broker Warrant Certificate representing the unexercised Broker Warrants will be issued and delivered with the certificate representing
the Common Shares.

At any time when there is no effective registration
statement under the United States Securities Act of 1933, as amended (the “U.S. Securities Act”), registering the Common
Shares issuable upon exercise of the Broker Warrants to which this Subscription Form relates, the undersigned must comply with the procedures
set forth in the paragraph immediately below.

The undersigned hereby certifies that the undersigned
(i) is not (and is not exercising the Broker Warrants for the account or benefit of) a person in the “United States or a “U.S.
Person”, (ii) did not execute or deliver this Subscription Form in the United States and (iii) has in all other aspects complied
with the terms of Regulation S under the United States Securities Act of 1933, as amended (the “U.S. Securities Act”),
or any successor rule or regulation of the United States Securities and Exchange Commission in effect. Alternatively, the undersigned
is tendering with this Subscription Form a written opinion of counsel or other evidence, in form and substance satisfactory to the Company,
to the effect that the securities to be delivered upon exercise of the Broker Warrants are exempt from registration under the U.S. Securities
Act and all applicable state securities laws. The term “U.S. Person” is as defined in Regulation S under the U.S. Securities
Act and includes, but is not limited to, any natural person resident in the United States and any partnership or corporation organized
or incorporated under the laws of the United States. “United States” means the United States of America, its territories and
possessions, any state of the United States and the District of Columbia.

 

The undersigned hereby directs that the Common
Shares be issued as follows:

	

NAME(S) IN FULL	

ADDRESS(ES)	NUMBER OF

COMMON SHARES
	 	 	 
	 	 	 
	 	 	 

 

DATED this                   
day of                                                     ,
20      .

	 	NAME:	 
	 	Signature of Authorized Representative:	 
	 	Print Name:

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