Citadel entities (NASDAQ: FCEL) disclose 3.8% FuelCell Energy position

Rhea-AI Filing Summary

FuelCell Energy, Inc. has institutional holders led by several Citadel-affiliated entities and Kenneth Griffin, who may be deemed to beneficially own up to 3,015,372 Shares, representing 3.8% of the Shares outstanding. Citadel Securities LLC alone may be deemed to beneficially own 2,146,714 Shares, or 2.7% of the class.

All reported parties have no sole voting or dispositive power; their reported positions reflect only shared voting and shared dispositive power over the relevant Shares. Percentages are based on 79,929,602 Shares outstanding as of July 8, 2026, and each reporting person disclaims beneficial ownership beyond securities actually owned.

Key Figures

Shares outstanding: 79,929,602 Shares Citadel Securities LLC beneficial ownership: 2,146,714 Shares (2.7%) Citadel Securities Group LP / GP LLC ownership: 3,015,372 Shares (3.8%) +3 more

6 metrics

Shares outstanding 79,929,602 Shares Shares outstanding as of July 8, 2026

Citadel Securities LLC beneficial ownership 2,146,714 Shares (2.7%) Citadel Securities LLC reported beneficial ownership

Citadel Securities Group LP / GP LLC ownership 3,015,372 Shares (3.8%) Each of Citadel Securities Group LP and Citadel Securities GP LLC

Kenneth Griffin beneficial ownership 3,015,372 Shares (3.8%) Kenneth Griffin may be deemed to beneficially own these Shares

Citadel Advisors LLC ownership 0 Shares (0.0%) Citadel Advisors LLC beneficial ownership reported

Shared voting power (Citadel Securities Group LP) 3,015,372 Shares Shared power to vote or direct the vote

Key Terms

beneficially own, shared voting power, shared dispositive power, percent of class, +1 more

5 terms

beneficially own financial

"Citadel Securities LLC may be deemed to beneficially own 2,146,714 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 voting power financial

"Shared Voting Power 3,015,372.00"

Shared voting power occurs when two or more parties jointly have the right to vote or decide how a block of company shares is cast, like co-owners who must agree before moving a piece of furniture. Investors care because who controls voting rights affects board elections, major corporate decisions and takeover outcomes, and shared control can alter regulatory disclosures and the practical influence any holder has over a company’s direction and value.

shared dispositive power financial

"Shared Dispositive Power 3,015,372.00"

percent of class financial

"Percent of class: ... constitutes 3.8% of the Shares outstanding."

Percent of class is the portion of a specific category of securities—such as a company’s common shares, preferred shares, or a bond series—that takes part in or approves a corporate action (vote, consent, tender, etc.). Investors watch this number because it reveals how much support or opposition exists within that particular shareholder group; like counting how many members of a club back a proposal, it can determine whether a plan passes or how influence is distributed.

attorney-in-fact regulatory

"Seth Levy is signing on behalf of Kenneth Griffin as attorney-in-fact"

An attorney-in-fact is the person or entity given legal authority through a power of attorney to act on behalf of another for specific tasks, such as signing documents, voting shares, or handling transactions. For investors, this matters because it lets a trusted representative make timely decisions or complete paperwork when the owner cannot, much like handing keys to someone to run errands on your behalf—so checks on scope and limits of that authority are important.

AI-generated analysis. How Rhea-AI works. Not financial advice.

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Available on EDGAR 08/04/2026 - 05:11 PM Accepted by SEC EDGAR 08/04/2026 - 05:11 PM Learn about SEC filing dates

FAQ

What stake in FuelCell Energy (FCEL) is reported by Citadel entities?

Citadel entities may be deemed to beneficially own up to 3,015,372 Shares of FuelCell Energy, Inc., representing 3.8% of the Shares outstanding, based on 79,929,602 Shares outstanding as of July 8, 2026.

How many FuelCell Energy (FCEL) shares does Citadel Securities LLC report?

Citadel Securities LLC may be deemed to beneficially own 2,146,714 Shares of FuelCell Energy, Inc., which constitutes 2.7% of the Shares outstanding, calculated using 79,929,602 Shares outstanding as of July 8, 2026.

What is Kenneth Griffin’s reported ownership in FuelCell Energy (FCEL)?

Kenneth Griffin may be deemed to beneficially own 3,015,372 Shares of FuelCell Energy, Inc., representing 3.8% of the outstanding Shares, with shared but not sole voting and dispositive power over these Shares.

What share count was used to calculate ownership percentages for FCEL?

Ownership percentages are based on 79,929,602 Shares outstanding as of July 8, 2026, as referenced from the issuer’s prospectus and Form 8-K. All reported percentage interests, such as 2.7% and 3.8%, use this share count.

Do the Citadel reporting persons have sole voting power over FuelCell Energy (FCEL) shares?

No reporting person has sole voting power over FuelCell Energy Shares. Reported positions reflect only shared voting power and shared dispositive power, with all parties showing 0 Shares for sole voting and sole dispositive power.

Which Citadel entities report zero beneficial ownership of FuelCell Energy (FCEL)?

Citadel Advisors LLC, Citadel Advisors Holdings LP, and Citadel GP LLC each may be deemed to beneficially own 0 Shares of FuelCell Energy, Inc., corresponding to 0.0% of the Shares outstanding, with no voting or dispositive power reported.

SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

FuelCell Energy, Inc.

(Name of Issuer)

Common Stock, $0.0001 par value per share (the "Shares")

(Title of Class of Securities)

35952H700

(CUSIP Number)

07/28/2026

(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): 35952H700

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 3,015,372.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 3,015,372.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

3,015,372.00

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)

3.8 %

12

Type of Reporting Person (See Instructions)

HC, OO

Comment for Type of Reporting Person: The percentages reported in this Schedule 13G are based upon 79,929,602 Shares outstanding as of July 8, 2026 (according to the issuer's prospectus as filed with the Securities and Exchange Commission on July 8, 2026, and the issuer's Form 8-K as filed with the Securities and Exchange Commission on July 9, 2026). 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 August 4, 2026.

SCHEDULE 13G

CUSIP Number(s): 35952H700

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 2,146,714.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 2,146,714.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

2,146,714.00

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)

2.7 %

12

Type of Reporting Person (See Instructions)

BD, OO

SCHEDULE 13G

CUSIP Number(s): 35952H700

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 3,015,372.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 3,015,372.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

3,015,372.00

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)

3.8 %

12

Type of Reporting Person (See Instructions)

HC, PN

SCHEDULE 13G

CUSIP Number(s): 35952H700

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 0.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

0.00

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)

0.0 %

12

Type of Reporting Person (See Instructions)

IA, HC, OO

SCHEDULE 13G

CUSIP Number(s): 35952H700

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 0.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

0.00

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)

0.0 %

12

Type of Reporting Person (See Instructions)

HC, PN

SCHEDULE 13G

CUSIP Number(s): 35952H700

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 0.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

0.00

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)

0.0 %

12

Type of Reporting Person (See Instructions)

HC, OO

SCHEDULE 13G

CUSIP Number(s): 35952H700

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 3,015,372.00
7	Sole Dispositive Power 0.00
8	Shared Dispositive Power 3,015,372.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

3,015,372.00

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)

3.8 %

12

Type of Reporting Person (See Instructions)

HC, IN

SCHEDULE 13G

Item 1.
(a)	Name of issuer: FuelCell Energy, Inc.
(b)	Address of issuer's principal executive offices: 3 Great Pasture Road, Danbury, CT, 06810
Item 2.
(a)	Name of person filing: This Schedule 13G is being jointly filed by Citadel Securities GP LLC ("CSGP"), Citadel Securities LLC ("Citadel Securities"), Citadel Securities Group LP ("CALC4"), Citadel Advisors LLC ("Citadel Advisors"), Citadel Advisors Holdings LP ("CAH"), Citadel GP LLC ("CGP"), and Mr. Kenneth Griffin (collectively with CSGP, Citadel Securities, CALC4, Citadel Advisors, CAH, and CGP, the "Reporting Persons") with respect to the Shares of the above-named issuer owned by Citadel Securities, Citadel Securities Principal Strategies LLC, a Delaware limited liability company ("CSP"), and CRBU Holdings LLC, a Delaware limited liability company ("CRBH"). Such owned Shares may include other instruments exercisable for or convertible into Shares. CALC4 is the non-member manager of Citadel Securities, CSP and CRBH. CSGP is the general partner of CALC4. CAH is the sole member of Citadel Advisors. CGP is the general partner of CAH. 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 CSGP, Citadel Securities, Citadel Advisors, and CGP 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 Stock, $0.0001 par value per share (the "Shares")
(e)	CUSIP Number(s): 35952H700
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. Citadel Securities LLC may be deemed to beneficially own 2,146,714 Shares. 2. Each of Citadel Securities Group LP and Citadel Securities GP LLC may be deemed to beneficially own 3,015,372 Shares. 3. Each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC may be deemed to beneficially own 0 Shares 4. Mr. Griffin may be deemed to beneficially own 3,015,372 Shares.
(b)	Percent of class: 1. The number of Shares that Citadel Securities LLC may be deemed to beneficially own constitutes 2.7% of the Shares outstanding. 2. The number of Shares that each of Citadel Securities Group LP and Citadel Securities GP LLC may be deemed to beneficially own constitutes 3.8% of the Shares outstanding. 3. 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 0.0% of the Shares outstanding. 4. The number of Shares that Mr. Griffin may be deemed to beneficially own constitutes 3.8% 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. Citadel Securities LLC: 0 2. Each of Citadel Securities Group LP and Citadel Securities GP LLC: 0 3. Each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC: 0 4. Mr. Griffin: 0
	(ii) Shared power to vote or to direct the vote: 1. Citadel Securities LLC: 2,146,714 2. Each of Citadel Securities Group LP and Citadel Securities GP LLC: 3,015,372 3. Each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC: 0 4. Mr. Griffin: 3,015,372
	(iii) Sole power to dispose or to direct the disposition of: 1. Citadel Securities LLC: 0 2. Each of Citadel Securities Group LP and Citadel Securities GP LLC: 0 3. Each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC: 0 4. Mr. Griffin: 0
	(iv) Shared power to dispose or to direct the disposition of: 1. Citadel Securities LLC: 2,146,714 2. Each of Citadel Securities Group LP and Citadel Securities GP LLC: 3,015,372 3. Each of Citadel Advisors LLC, Citadel Advisors Holdings LP and Citadel GP LLC: 0 4. Mr. Griffin: 3,015,372
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 Securities GP LLC

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

Citadel Securities LLC

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

Citadel Securities Group LP

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

Citadel Advisors LLC

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

Citadel Advisors Holdings LP

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

Citadel GP LLC

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

Kenneth Griffin

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

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