Capital World Investors Discloses 13.9% Stake in Quantinuum

Quantinuum Inc. reports that Capital World Investors holds 4,558,976 shares of Common Stock, representing 13.9% of the company as of 06/30/2026.

Accepted by SEC EDGAR 07/06/2026 - 07:47 PM EDT Learn about SEC filing dates

Rhea-AI Filing Summary

Quantinuum Inc. reports that Capital World Investors holds 4,558,976 shares of Common Stock, representing 13.9% of the company as of 06/30/2026. The filing states the 4,558,976 shares reflect sole voting and dispositive power. The filing cites 32,862,895 shares believed to be outstanding as context.

Insights

Institutional Investor Relations Analyst

CWI discloses a large passive stake of 13.9% in Quantinuum as of 06/30/2026.

Capital World Investors reports beneficial ownership of 4,558,976 shares with sole voting and dispositive power, indicating control over voting decisions for those shares. The filing identifies the stake as 13.9% of 32,862,895 shares believed outstanding.

This Schedule 13G is a routine beneficial-ownership disclosure for an institutional investor. Subsequent filings could show changes if CWI adjusts its position or files under different reporting rules.

Key Figures

Beneficial ownership: 4,558,976 shares Ownership percentage: 13.9% Shares outstanding (believed): 32,862,895 shares

3 metrics

Beneficial ownership 4,558,976 shares Amount beneficially owned as reported by Capital World Investors

Ownership percentage 13.9% Percent of class based on 32,862,895 shares believed outstanding

Shares outstanding (believed) 32,862,895 shares Shares believed to be outstanding used to compute 13.9% figure

Key Terms

beneficially owned, sole voting power, Schedule 13G

3 terms

beneficially owned regulatory

"CWI is deemed to be the beneficial owner of 4,558,976 shares or 13.9% of the 32,862,895 shares"

Beneficially owned describes securities or assets where a person has the economic rights and control—such as the right to receive dividends and to direct voting—even if legal title is held in another name. Think of it like having the keys and using a car that’s registered to someone else: you get the benefits and make decisions. Investors care because beneficial ownership reveals who truly controls value and voting power, affecting corporate decisions and takeover dynamics.

sole voting power regulatory

"Sole power to vote or to direct the vote: 4,558,976"

Sole voting power is the exclusive right to cast votes attached to a shareholder’s stock without needing approval from anyone else. Like holding the only remote control for a TV, it lets that holder decide corporate matters such as board members, mergers, and policy changes, making it important to investors because it concentrates control and can strongly influence a company’s strategy and the value of its shares.

Schedule 13G regulatory

"Item 1. (a) Name of issuer: Quantinuum Inc."

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.

FAQ

AI-generated questions and answers. How Rhea-AI works. Not financial advice.

What stake does Capital World Investors report in Quantinuum (QNT)?

Capital World Investors reports beneficial ownership of 4,558,976 shares, equal to 13.9% of Quantinuum's outstanding common stock as of 06/30/2026. The filing states these shares are held with sole voting and dispositive power.

How many shares does Quantinuum state are outstanding in the filing?

The filing cites 32,862,895 shares believed to be outstanding. This outstanding share count is presented as the basis for the 13.9% ownership percentage reported by Capital World Investors.

Does the Schedule 13G show whether Capital World Investors can vote or sell the shares?

Yes. The filing states CWI has sole voting power and sole dispositive power over 4,558,976 shares, indicating the ability to vote and direct dispositions for those shares.

Was the Schedule 13G signed and dated?

The filing includes an electronic signature by Jae Won Chung, Senior Vice President and Associate General Counsel, Capital Research and Management Company, dated 07/02/2026, certifying the reported ownership information.

Is the reported 13.9% stake held on behalf of other entities?

The filing states Capital World Investors is a division of Capital Research and Management Company and lists related investment management entities. It also names American Funds Insurance Series Asset Allocation Fund among accounts but does not allocate specific shares to each account.

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

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SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G

UNDER THE SECURITIES EXCHANGE ACT OF 1934

Quantinuum Inc.

(Name of Issuer)

Common Stock

(Title of Class of Securities)

74768A104

(CUSIP Number)

06/30/2026

(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): 74768A104

1

Names of Reporting Persons

Capital World Investors

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 4,558,976.00
6	Shared Voting Power 0.00
7	Sole Dispositive Power 4,558,976.00
8	Shared Dispositive Power 0.00

9

Aggregate Amount Beneficially Owned by Each Reporting Person

4,558,976.00

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)

13.9 %

12

Type of Reporting Person (See Instructions)

IA

SCHEDULE 13G

Item 1.
(a)	Name of issuer: Quantinuum Inc.
(b)	Address of issuer's principal executive offices: 303 S Technology Court, Broomfield, CO 80021
Item 2.
(a)	Name of person filing: Capital World Investors
(b)	Address or principal business office or, if none, residence: 333 SOUTH HOPE STREET, 55TH FLOOR, LOS ANGELES, CALIFORNIA 90071
(c)	Citizenship: N/A
(d)	Title of class of securities: Common Stock
(e)	CUSIP Number(s): 74768A104
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: 4,558,976 ** **Capital World Investors ("CWI") is a division of Capital Research and Management Company ("CRMC"), as well as its investment management subsidiaries and affiliates Capital Bank and Trust Company, Capital International, Inc., Capital International Limited, Capital International Sarl, Capital International K.K., Capital Group Private Client Services, Inc., and Capital Group Investment Management Private Limited (together with CRMC, the "investment management entities"). CWI's divisions of each of the investment management entities collectively provide investment management services under the name "Capital World Investors." CWI is deemed to be the beneficial owner of 4,558,976 shares or 13.9% of the 32,862,895 shares believed to be outstanding.
(b)	Percent of class: 13.9 %
(c)	Number of shares as to which the person has:
	(i) Sole power to vote or to direct the vote: 4,558,976
	(ii) Shared power to vote or to direct the vote: 0
	(iii) Sole power to dispose or to direct the disposition of: 4,558,976
	(iv) Shared power to dispose or to direct the disposition of: 0
Item 5.	Ownership of 5 Percent or Less of a Class.
	Not Applicable
Item 6.	Ownership of more than 5 Percent on Behalf of Another Person.
	If any other person is known to have the right to receive or the power to direct the receipt of dividends from, or the proceeds from the sale of, such securities, a statement to that effect should be included in response to this item and, if such interest relates to more than 5 percent of the class, such person should be identified. A listing of the shareholders of an investment company registered under the Investment Company Act of 1940 or the beneficiaries of employee benefit plan, pension fund or endowment fund is not required. American Funds Insurance Series Asset Allocation Fund
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 acquired and are held in the ordinary course of business and 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.

Capital World Investors

Signature:	Jae Won Chung
Name/Title:	Senior Vice President and Associate General Counsel, Capital Research and Management Company
Date:	07/02/2026