Citadel entities and Kenneth Griffin disclose NB holdings (NB)

Rhea-AI Filing Summary

NioCorp Developments Ltd. received a joint Schedule 13G reporting that Citadel entities and Kenneth Griffin beneficially hold disclosed positions in the company's Common Shares. The filing lists Citadel Advisors LLC (4,932,309 shares, 3.4%), Citadel Securities LLC (441,050 shares, 0.3%) and Kenneth Griffin (6,216,351 shares, 4.3%). The percentages are based on 145,327,592 Shares outstanding, comprised of 142,727,542 Shares outstanding as of February 25, 2026, plus 2,600,000 and 50 shares issued on conversion of certain warrants. The filing is a joint disclosure of holdings and voting/dispositive arrangements among the reporting persons.

Key Figures

Shares outstanding: 145,327,592 shares Citadel Advisors holdings: 4,932,309 shares Citadel Securities holdings: 441,050 shares +3 more

6 metrics

Shares outstanding 145,327,592 shares calculation basis including conversions, as stated in filing

Citadel Advisors holdings 4,932,309 shares beneficial ownership reported for Citadel Advisors LLC

Citadel Securities holdings 441,050 shares beneficial ownership reported for Citadel Securities LLC

Kenneth Griffin holdings 6,216,351 shares beneficial ownership reported for Kenneth Griffin

Shares outstanding as of date 142,727,542 shares Shares outstanding as of <date>February 25, 2026</date>

Warrants converted 2,600,050 shares 2,600,000 and 50 shares issued upon conversion of certain warrants

Key Terms

Beneficially own, Shared Dispositive Power, Schedule 13G

3 terms

Beneficially own regulatory

"Each of Citadel Advisors LLC ... may be deemed to beneficially own 4,932,309 Shares."

Beneficially own means having the economic rights and risks of a security—such as the right to receive dividends, sell the shares, or profit from price changes—whether or not your name appears on the official share register. Think of it like renting a car: you use it and reap the benefits even if the title lists someone else. Investors care because beneficial ownership determines who truly controls value, must be disclosed under securities rules, and can signal potential influence or trading activity that affects a stock’s price.

Shared Dispositive Power regulatory

"Shared Dispositive Power 4,932,309.00"

Schedule 13G regulatory

"This is being jointly filed by Citadel Advisors LLC ... (the "Reporting Persons")."

A Schedule 13G is a formal document that investors file with the government when they acquire a large ownership stake in a company, usually for investment purposes rather than control. It helps keep the public informed about who owns significant parts of a company's shares, which can influence how the company is managed and how investors make decisions. Filing this schedule is important for transparency and understanding the ownership landscape of publicly traded companies.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

NioCorp Developments Ltd.

(Name of Issuer)

Common Shares, without par value (the "Shares")

(Title of Class of Securities)

654484609

(CUSIP Number)

02/25/2026

(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

Rule 13d-1(b)

Rule 13d-1(c)

Rule 13d-1(d)

schemaVersion:

SCHEDULE 13G

CUSIP Number(s): 654484609

1

Names of Reporting Persons

Citadel Advisors LLC

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 4,932,309.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 4,932,309.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

4,932,309.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

3.4 %

12

Type of Reporting Person (See Instructions)

IA, HC, OO

Comment for Type of Reporting Person: The percentages reported in this Schedule 13G are based upon 145,327,592 Shares outstanding comprised of (i) 142,727,542 Shares outstanding as of February 25, 2026 (according to the issuer's prospectus as filed with the Securities and Exchange Commission on February 25, 2026), (ii) 2,600,000 Shares issued upon conversion of certain warrants held by affiliates of the reporting persons, and (iii) 50 Shares issuable upon conversion of certain warrants held by affiliates of the reporting persons. Except as described in the preceding sentence, all Shares for the holdings of the reporting persons reported in this Schedule 13G are as of the opening of the market on April 8, 2026.

SCHEDULE 13G

CUSIP Number(s): 654484609

1

Names of Reporting Persons

Citadel Advisors Holdings LP

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 4,932,309.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 4,932,309.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

4,932,309.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

3.4 %

12

Type of Reporting Person (See Instructions)

HC, PN

SCHEDULE 13G

CUSIP Number(s): 654484609

1

Names of Reporting Persons

Citadel GP LLC

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 4,932,309.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 4,932,309.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

4,932,309.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

3.4 %

12

Type of Reporting Person (See Instructions)

HC, OO

SCHEDULE 13G

CUSIP Number(s): 654484609

1

Names of Reporting Persons

Citadel Securities LLC

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 441,050.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 441,050.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

441,050.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

0.3 %

12

Type of Reporting Person (See Instructions)

BD, OO

SCHEDULE 13G

CUSIP Number(s): 654484609

1

Names of Reporting Persons

Citadel Securities Group LP

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,284,042.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,284,042.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,284,042.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

0.9 %

12

Type of Reporting Person (See Instructions)

HC, PN

SCHEDULE 13G

CUSIP Number(s): 654484609

1

Names of Reporting Persons

Citadel Securities GP LLC

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

DELAWARE

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 1,284,042.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 1,284,042.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

1,284,042.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

0.9 %

12

Type of Reporting Person (See Instructions)

HC, OO

SCHEDULE 13G

CUSIP Number(s): 654484609

1

Names of Reporting Persons

Kenneth Griffin

2

Check the appropriate box if a member of a Group (see instructions)

(a)
(b)

3

Sec Use Only

4

Citizenship or Place of Organization

UNITED STATES

Number of Shares Beneficially Owned by Each Reporting Person With:

5	Sole Voting Power 0.00
6	Shared Voting Power 6,216,351.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 6,216,351.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

6,216,351.00

10

Check box if the aggregate amount in row (9) excludes certain shares (See Instructions)

11

Percent of class represented by amount in row (9)

4.3 %

12

Type of Reporting Person (See Instructions)

HC, IN

SCHEDULE 13G

Item 1.
(a)	Name of issuer: NioCorp Developments Ltd.
(b)	Address of issuer's principal executive offices: 7000 South Yosemite Street, Suite 115, Centennial, CO 80112
Item 2.
(a)	Name of person filing: This Schedule 13G is being jointly filed by Citadel Advisors LLC ("Citadel Advisors"), Citadel Advisors Holdings LP ("CAH"), Citadel GP LLC ("CGP"), Citadel Securities LLC ("Citadel Securities"), Citadel Securities Group LP ("CALC4"), Citadel Securities GP LLC ("CSGP") and Mr. Kenneth Griffin (collectively with Citadel Advisors, CAH, CGP, Citadel Securities, CALC4 and CSGP, the "Reporting Persons") with respect to the Shares of the above-named issuer owned by Citadel CEMF Investments Ltd., a Cayman Islands limited company ("CCIL"), Citadel Multi-Asset Fund (Ireland) Designated Activity Company, an Ireland company ("CMI"), Citadel Securities and CRBU Holdings LLC, a Delaware limited liability company ("CRBH"). Such owned Shares may include other instruments exercisable for or convertible into Shares. Citadel Advisors is the portfolio manager for CCIL and CMI. CAH is the sole member of Citadel Advisors. CGP is the general partner of CAH. CALC4 is the non-member manager of Citadel Securities and CRBH. CSGP is the general partner of CALC4. Mr. Griffin is the President and Chief Executive Officer of CGP, and owns a controlling interest in CGP and CSGP. The filing of this statement shall not be construed as an admission that any of the Reporting Persons is the beneficial owner of any securities covered by the statement other than the securities actually owned by such person (if any).
(b)	Address or principal business office or, if none, residence: The address of each of the Reporting Persons is 830 Brickell Plaza, Miami, Florida 33131.
(c)	Citizenship: Each of Citadel Advisors, CGP, Citadel Securities and CSGP is organized as a limited liability company under the laws of the State of Delaware. Each of CALC4 and CAH is organized as a limited partnership under the laws of the State of Delaware. Mr. Griffin is a U.S. citizen.
(d)	Title of class of securities: Common Shares, without par value (the "Shares")
(e)	CUSIP Number(s): 654484609
Item 3.	If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:
(a)	Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o);
(b)	Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c);
(c)	Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c);
(d)	Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8);
(e)	An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);
(f)	An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);
(g)	A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);
(h)	A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);
(i)	A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);
(j)	A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J). If filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:
(k)	Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).
Item 4.	Ownership
(a)	Amount beneficially owned: 1. Each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC may be deemed to beneficially own 4,932,309 Shares. 2. Citadel Securities LLC may be deemed to beneficially own 441,050 Shares. 3. Each of Citadel Securities Group LP and Citadel Securities GP LLC may be deemed to beneficially own 1,284,042 Shares. 4. Mr. Griffin may be deemed to beneficially own 6,216,351 Shares.
(b)	Percent of class: 1. The number of Shares that each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC may be deemed to beneficially own constitutes 3.4% of the Shares outstanding. 2. The number of Shares that Citadel Securities LLC may be deemed to beneficially own constitutes 0.3% of the Shares outstanding. 3. The number of Shares that each of Citadel Securities Group LP and Citadel Securities GP LLC may be deemed to beneficially own constitutes 0.9% of the Shares outstanding. 4. The number of Shares that Mr. Griffin may be deemed to beneficially own constitutes 4.3% of the Shares outstanding.
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 1. Each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC: 0 2. Citadel Securities LLC: 0 3. Each of Citadel Securities Group LP and Citadel Securities GP LLC: 0 4. Mr. Griffin: 0
	(ii) Shared power to vote or to direct the vote: 1. Each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC: 4,932,309 2. Citadel Securities LLC: 441,050 3. Each of Citadel Securities Group LP and Citadel Securities GP LLC: 1,284,042 4. Mr. Griffin: 6,216,351
	(iii) Sole power to dispose or to direct the disposition of: 1. Each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC: 0 2. Citadel Securities LLC: 0 3. Each of Citadel Securities Group LP and Citadel Securities GP LLC: 0 4. Mr. Griffin: 0
	(iv) Shared power to dispose or to direct the disposition of: 1. Each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC: 4,932,309 2. Citadel Securities LLC: 441,050 3. Each of Citadel Securities Group LP and Citadel Securities GP LLC: 1,284,042 4. Mr. Griffin: 6,216,351
Item 5.	Ownership of 5 Percent or Less of a Class.
	Ownership of 5 percent or less of a class
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	Not Applicable
Item 7.	Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Control Person.
	Not Applicable
Item 8.	Identification and Classification of Members of the Group.
	Not Applicable
Item 9.	Notice of Dissolution of Group.
	Not Applicable

Item 10.

Certifications:

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under ?? 240.14a-11.

SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Citadel Advisors LLC

Signature:	/s/ Seth Levy
Name/Title:	Seth Levy, Authorized Signatory
Date:	04/08/2026

Citadel Advisors Holdings LP

Signature:	/s/ Seth Levy
Name/Title:	Seth Levy, Authorized Signatory
Date:	04/08/2026

Citadel GP LLC

Signature:	/s/ Seth Levy
Name/Title:	Seth Levy, Authorized Signatory
Date:	04/08/2026

Citadel Securities LLC

Signature:	/s/ Seth Levy
Name/Title:	Seth Levy, Authorized Signatory
Date:	04/08/2026

Citadel Securities Group LP

Signature:	/s/ Seth Levy
Name/Title:	Seth Levy, Authorized Signatory
Date:	04/08/2026

Citadel Securities GP LLC

Signature:	/s/ Seth Levy
Name/Title:	Seth Levy, Authorized Signatory
Date:	04/08/2026

Kenneth Griffin

Signature:	/s/ Seth Levy
Name/Title:	Seth Levy, attorney-in-fact*
Date:	04/08/2026

Comments accompanying signature: * Seth Levy is signing on behalf of Kenneth Griffin as attorney-in-fact pursuant to a power of attorney previously filed with the Securities and Exchange Commission, and hereby incorporated by reference herein. The power of attorney was filed as an attachment to a filing by Citadel Advisors LLC on Schedule 13G for Allakos Inc. on October 13, 2023.

Exhibit Information

Exhibit 99.1 - Joint Filing Agreement

FAQ

What does Citadel's Schedule 13G filing for NioCorp (NB) disclose?

It discloses that Citadel-related entities and Kenneth Griffin report beneficial holdings in NioCorp. The filing lists specific share counts such as 4,932,309 shares for Citadel Advisors and 6,216,351 shares for Kenneth Griffin, with percentages tied to 145,327,592 outstanding shares.

How was the percent ownership calculated in the NB filing?

Percentages are calculated using 145,327,592 Shares outstanding. That total is described as 142,727,542 Shares outstanding as of February 25, 2026 plus 2,600,000 and 50 shares issued on conversion of certain warrants held by affiliates.

What voting and dispositive powers are reported in the Schedule 13G?

The filing shows the reporting persons generally report 0 sole voting and 0 sole dispositive power and instead report shared voting and dispositive power. For example, Citadel Advisors reports 4,932,309 shared voting and dispositive shares.

Does the Schedule 13G indicate any change in control of NioCorp (NB)?

No change of control is asserted. The filing lists beneficial ownership percentages (each below typical control thresholds) and states the filing shall not be construed as admission of beneficial ownership beyond the securities actually owned by each reporting person.

Who signed the joint Schedule 13G for these Citadel reporting persons?

The statement is signed by Seth Levy as authorized signatory on behalf of multiple Citadel entities and as attorney-in-fact for Kenneth Griffin, with signatures dated 04/08/2026.